阅读说明：本技术 聚合物壳式矫治器及其制造方法 (Polymeric shell appliances and methods of making the same ) 是由 A·科佩尔曼 J·莫顿 于 2016-07-07 设计创作，主要内容包括：提供聚合物壳式矫治器及其制造方法,其中该聚合物壳式矫治器被构造成用于提供一个或多个促动力以利于牙齿移动。在很多实施例中,此矫治器包括邻间接合结构,以向邻间牙齿表面提供促动力。在很多实施例中,此促动力被设置成提供多个力,包括沿与牙齿移动的预期方向相反的方向的力。该聚合物壳式矫治器可包括一个或多个牙齿接纳腔,其中所述多个牙齿接纳腔中的每一个均被成形为且被设置为提供多颗牙齿中的每颗牙齿的反力矩。(Polymeric shell appliances and methods of making the same are provided, wherein the polymeric shell appliances are configured to provide one or more actuating forces to facilitate tooth movement. In many embodiments, the appliance includes an interproximal engagement structure to provide an actuating force to the interproximal tooth surfaces. In many embodiments, this actuation force is configured to provide a plurality of forces, including a force in a direction opposite to the intended direction of tooth movement. The polymeric shell appliance may include one or more tooth receiving cavities, wherein each of the plurality of tooth receiving cavities is shaped and arranged to provide a counter moment for each of a plurality of teeth.)

1. A polymeric shell appliance for moving a first tooth of a patient from a first position and orientation to a second position and orientation, the polymeric shell appliance comprising a plurality of tooth receiving cavities shaped to receive teeth of a patient, the plurality of tooth receiving cavities comprising:

a first tooth receiving cavity shaped to receive the first tooth;

a second tooth receiving cavity shaped to receive a second tooth adjacent the first tooth;

a buccal sidewall extending from the first tooth receiving cavity to the second tooth receiving cavity on a buccal side of the appliance;

a lingual sidewall extending from the first tooth receiving cavity to the second tooth receiving cavity on a lingual side of the appliance; and

a polymeric interproximal engagement structure extending from the lingual sidewall or the buccal sidewall into an interproximal space defined by the first tooth, the second tooth, the patient's gums, and a location of minimum distance between the first tooth and the second tooth,

wherein the polymeric interproximal engagement structures are shaped to contact the first tooth to apply a force to the first tooth from the interproximal space and to move the tooth from the first position and orientation to the second position and orientation when the appliance is worn.

2. A method of manufacturing a polymeric shell appliance for moving a first tooth of a patient, the method comprising:

determining a movement path to move the first tooth from a first position and orientation to a second position and orientation;

determining a force system to produce movement of the first tooth along the movement path;

determining an appliance geometry for an orthodontic appliance configured to generate the force system; and

manufacturing the orthodontic appliance based on the determined appliance geometry, wherein the orthodontic appliance is a polymeric shell appliance comprising a plurality of tooth receiving cavities including:

a first tooth receiving cavity shaped to receive the first tooth;

a second tooth receiving cavity shaped to receive a second tooth adjacent the first tooth;

a buccal sidewall extending from the first tooth receiving cavity to the second tooth receiving cavity on a buccal side of the appliance;

a lingual sidewall extending from the first tooth receiving cavity to the second tooth receiving cavity on a lingual side of the appliance; and

a polymeric interproximal engagement structure extending from the lingual sidewall or the buccal sidewall into an interproximal space defined by the first tooth, the second tooth, the patient's gums, and a location of minimum distance between the first tooth and the second tooth,

wherein the polymeric interproximal engagement structures are shaped to contact the first tooth to apply a force to the first tooth from the interproximal space and to move the tooth from the first position and orientation to the second position and orientation along the path of movement when the appliance is worn.

3. A polymeric shell appliance for moving a first tooth of a patient from a first position and orientation to a second position and orientation, the polymeric shell appliance comprising a plurality of tooth receiving cavities shaped to receive teeth of the patient, the plurality of tooth receiving cavities comprising:

a first tooth receiving cavity shaped to receive the first tooth, the first tooth receiving cavity defined by a shell wall having a first thickness;

a tooth engaging structure at a gingival end of the shell wall,

wherein the tooth engaging structure is configured to engage the bite edge of the first tooth to exert an extrusion force on the teeth when the polymeric shell appliance is worn by a patient.

4. A polymeric shell appliance for moving a first tooth of a patient from a first position and orientation to a second position and orientation, the polymeric shell appliance comprising a plurality of tooth receiving cavities shaped to receive teeth of the patient, the plurality of tooth receiving cavities comprising:

a first tooth receiving cavity shaped to receive the first tooth, the first tooth receiving cavity defined by a shell wall having a varying thickness, wherein:

the shell wall also includes a smooth outer surface and an irregular inner surface,

the inner surface includes a plurality of projections extending toward the teeth, and

the plurality of protrusions correspond to locations of increased thickness of the shell.

5. A polymeric shell appliance for closing a gap between a first tooth of a plurality of teeth of a patient and a second tooth of the plurality of teeth of a patient, comprising:

a first shell wall formed from a first polymer material and defining a first tooth receiving cavity to receive the first tooth;

a second shell wall formed from the first polymeric material and defining a second tooth receiving cavity to receive the second tooth;

a gap portion formed from a second polymeric material extending between the first housing wall and the second housing wall,

wherein the second polymeric material is more flexible than the first polymeric material, and wherein the gap is arranged to stretch and apply a resilient force to urge the first and second teeth together when the first and second teeth are received in the first and second tooth-receiving cavities.

6. A plurality of polymeric shell appliances for moving a first tooth of a patient from a first position and orientation to a second position and orientation, each polymeric shell appliance of the plurality of polymeric shell appliances comprising a plurality of tooth receiving cavities shaped to receive teeth of the patient, the plurality of tooth receiving cavities comprising:

a first tooth receiving cavity shaped to receive the first tooth;

a second tooth receiving cavity shaped to receive a second tooth adjacent the first tooth;

a buccal sidewall extending from the first tooth receiving cavity to the second tooth receiving cavity on a buccal side of the appliance;

a lingual sidewall extending from the first tooth receiving cavity to the second tooth receiving cavity on a lingual side of the appliance; and

a polymeric interproximal engagement structure extending from the lingual sidewall through the interproximal space between the first tooth and the second tooth to the buccal sidewall,

wherein the respective polymeric interproximal engagement structures of the plurality of appliances are arranged at different angles relative to the buccal sidewall such that when the plurality of polymeric shell appliances are worn in sequence, the respective polymeric interproximal engagement structures apply varying rotational forces to the first and second teeth.

7. A polymeric shell appliance for increasing the gap between a first tooth and a second tooth, the polymeric shell appliance comprising:

a first tooth receiving cavity shaped to receive the first tooth;

a second tooth receiving cavity shaped to receive the second tooth;

a first sidewall extending from the first tooth receiving cavity to the second tooth receiving cavity on a lingual side of the appliance;

a second sidewall extending from the first tooth receiving cavity to the second tooth receiving cavity on a buccal side of the appliance; and

an interproximal engagement structure disposed on the first sidewall or the second sidewall and positioned to extend into an interproximal space between the first tooth and the second tooth, wherein

The first sidewall and the second sidewall comprise a first polymeric material,

the interproximal engagement structures comprise a second polymeric material,

one of the first and second polymeric materials has greater elasticity than the other of the first and second polymeric materials, and

the appliance is configured to deform the one of the first and second polymeric materials having the greater elasticity while the other of the first and second polymeric materials is not substantially deformed when the appliance is worn, thereby generating an elastic force that urges the first and second teeth apart.

8. A polymeric shell appliance for moving a first tooth of a patient from a first position and orientation to a second position and orientation, the polymeric shell appliance comprising a plurality of tooth receiving cavities shaped to receive teeth of the patient, the plurality of tooth receiving cavities comprising:

a first tooth receiving cavity shaped to receive the first tooth;

a second tooth receiving cavity shaped to receive a second tooth adjacent the first tooth;

a third tooth-receiving cavity shaped to receive a third tooth adjacent the first tooth;

a buccal sidewall extending from the first tooth receiving cavity to the second tooth receiving cavity on a buccal side of the appliance;

a lingual sidewall extending from the first tooth receiving cavity to the second tooth receiving cavity on a lingual side of the appliance;

a first interproximal engagement structure extending from the lingual sidewall or the buccal sidewall into an interproximal space defined by the first tooth, the second tooth, the patient's gums, and a location of minimum distance between the first tooth and the second tooth; and

a first bite engagement structure extending from the lingual sidewall or the buccal sidewall between the first tooth and the third tooth and proximate an occlusal surface of the first tooth,

wherein the first interproximal engagement structures are shaped to contact the first tooth to apply forces and moments to the first tooth from the interproximal spaces when the appliance is worn, and the first bite engagement structures are shaped to contact the first tooth to apply forces proximate to the occlusal surface of the first tooth to provide counter-moments to the first tooth when the appliance is worn.

9. A polymeric shell appliance comprising:

an outer wall shaped to extend over exposed buccal, lingual and occlusal surfaces of a plurality of teeth when the appliance is worn; and

a plurality of interproximal engagement structures sized to extend into the interproximal spaces of the teeth and coupled to the outer wall on the buccal and lingual sides of the wall when the polymeric shell appliance is worn;

wherein the polymeric shell appliance is configured to contact at least about 60% of the circumferential surface of the plurality of teeth when the polymeric shell appliance is worn.

Background

Existing methods and devices for moving (displacing) teeth may be undesirable in at least some respects. Although transparent shell appliances (transparent shell appliances) are effective in moving teeth, complex tooth movement can be facilitated by the use of attachments to the teeth that engage the appliance to move the teeth. While attachments may be effective, such attachments on the teeth may be somewhat inconvenient for the patient. It would be helpful to move teeth with a transparent shell appliance with fewer attachments.

Disclosure of Invention

The methods and devices disclosed herein provide improved movement of teeth via an interproximal engagement structure. The interproximal engagement structures can extend at least partially into the interproximal spaces of the teeth to engage the teeth. The interproximal engagement can allow a greater amount of tooth surface engagement with the appliance in order to achieve more precise tooth movement. In addition, the aforementioned interproximal engagement enables access to the teeth at a location that is advantageous for facilitating tooth movement. In many embodiments, the interproximal engagement of a tooth may be opposed to the engagement of the tooth at another location on the opposite side of the tooth, thereby increasing one or more torques of the tooth or facilitating rotation of the tooth. The teeth may be interproximally engaged on a first side and proximate an occlusal surface on a second side opposite the first side in order to induce torque or rotation. The interproximal engagement can provide engagement closer to the center of rotation of the teeth than the position on the opposite side, thereby inducing torque. In many embodiments, a pair of interproximal structures of the appliance are configured to engage the teeth on the buccal (and lingual) surfaces to provide better engagement and improved tooth movement. These interproximal structures can be used to control the rotation of the teeth to improve tooth movement, but also provide better anchoring. The interproximal structures described above can be used to anchor the appliance to the posterior teeth (e.g., molars), as well as to facilitate movement of the anterior teeth to close the extraction site by engagement of the anchored molars. Alternatively or in combination, interproximal structures can also be used to treat dental spaces (diastema) or to induce midline shifts (midline shift).

In many embodiments, the oral cavity of a patient is scanned to provide three-dimensional contour data of the patient's oral cavity. Three-dimensional contour data of a patient's teeth can be used to determine a three-dimensional shape contour of an appliance having an interproximal structure. Appliances including interproximal structures can be manufactured directly. The appliance may include one of a plurality of appliances to move teeth according to a treatment plan and to be able to determine the position of the interproximal structures according to the treatment plan.

Incorporation by reference

All publications, patents and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference.

Drawings

The novel features of the invention are set forth with particularity in the appended claims. The features and advantages of the present disclosure will be better understood by referring to the following detailed description, which sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:

fig. 1A shows a tooth repositioning appliance, according to an embodiment;

FIG. 1B illustrates a tooth repositioning system according to an embodiment;

fig. 1C illustrates a method of orthodontic treatment (dental correction) using multiple appliances, according to an embodiment;

FIG. 2 illustrates a plurality of components of an orthotic appliance (alignment apparatus) and corresponding forces, according to an embodiment;

fig. 3A illustrates a method of designing an orthodontic appliance according to an embodiment;

fig. 3B illustrates a method of digitally formulating an orthodontic treatment plan, according to an embodiment;

FIG. 4 is a simplified block diagram of a data processing system according to an embodiment;

fig. 5A illustrates an engagement mechanism between a manufactured shell (fabricated shell) and teeth 503, according to an embodiment;

FIG. 5B illustrates another coupling mechanism between a shell 511 and a tooth being manufactured, in accordance with embodiments;

FIG. 5C illustrates how the shell as manufactured may engage the bite edge (undercut) of a tooth, according to an embodiment;

FIGS. 5D and 5E illustrate other options in the design that may be used for the manufactured housing, according to embodiments;

FIG. 6 illustrates a force that may be applied to induce rotation of a tooth about a vertical axis, in accordance with an embodiment;

fig. 7A illustrates a force that may be effectively applied to a tooth through the use of a manufactured engagement structure (e.g., an interproximal engagement structure), according to an embodiment;

fig. 7B illustrates a plurality of exemplary positions in which the interproximal engagement structures may be designed to engage the teeth, in accordance with an embodiment;

fig. 8A illustrates another configuration of a directly fabricated shell that allows for translational movement of one or more teeth, in accordance with an embodiment;

fig. 8B illustrates how an interproximal engagement structure can be applied to assist in anchoring the shell being manufactured to one or more teeth, in accordance with an embodiment;

fig. 9A illustrates how a plurality of tooth engaging structures can be configured to treat an interdental space, according to an embodiment;

fig. 9B illustrates how interproximal tooth engagement structures can be used to cause midline shift, according to an embodiment;

fig. 9C illustrates how a pair of interproximal tooth engaging structures oppositely disposed on the buccal and lingual sides of the teeth can be used to apply tooth-moving forces in any of the various configurations described herein, in accordance with an embodiment;

figure 9D illustrates how an appliance can be made from both an elastomeric material and a rigid material such that the tooth engaging structure exerts a force on the teeth, according to an embodiment;

FIG. 10A illustrates a plurality of appliances having interproximal engagement structures with varying interproximal widths;

FIG. 10B illustrates a plurality of appliances having interproximal engagement structures disposed at different angles;

FIG. 11 illustrates a plurality of appliances having interproximal engagement structures of different bucco-lingual lengths configured to apply force to teeth with the walls of the appliances;

FIG. 12A illustrates an appliance having an interproximal engagement structure coupled to the resilient wall, positioned and shaped to urge movement of the teeth;

FIG. 12B illustrates an appliance having an interproximal engagement structure which includes a resilient material, is positioned and shaped to urge movement of the teeth;

FIG. 13A illustrates an appliance wherein a first interproximal engagement structure passes through a first interproximal region between two first teeth and a second interproximal engagement structure passes through a second interproximal region between two second teeth;

FIG. 13B illustrates an appliance having a single interproximal engagement structure positioned to span the interproximal spaces between the teeth;

FIG. 13C illustrates an arrangement for applying a plurality of forces to teeth via an interproximal engagement structure to provide a resultant tooth movement force; and

FIG. 14 illustrates an exemplary structure that may be used in an appliance having an interproximal engagement structure with a projection having a radius of curvature less than one-third of its thickness.

Detailed Description

In many embodiments, a method for moving a patient's teeth from a first position and orientation to a second position and orientation is provided. The method includes providing a polymeric shell appliance shaped to fit a plurality of teeth. The polymeric shell appliance includes a polymeric interproximal engagement structure sized to extend across the interproximal spaces of the teeth from the lingual side to the buccal side. The polymeric shell appliance also includes one or more tooth receiving cavities to couple (couple) teeth to another one or more of the plurality of teeth via another one or more tooth receiving cavities. When worn, the interproximal engagement structures apply forces to the teeth from the interproximal spaces to move the teeth from the first position and orientation to the second position and orientation.

In some embodiments, each interproximal engagement structure includes a width extending between adjacent teeth defining interproximal spaces, wherein the widths sequentially increase in the plurality of appliances so as to sequentially increase the distance between adjacent teeth. In some embodiments, each interproximal engagement structure includes opposing contact surfaces to engage adjacent teeth defining interproximal spaces, and wherein the angle of these contact surfaces relative to each other is varied (different) among the plurality of appliances in order to move the teeth from a first position and orientation to a second position and orientation.

In many embodiments, a method for moving a patient's teeth from a first position and orientation to a second position and orientation is provided. In turn, a plurality of orthodontic appliances are provided that are shaped to fit a plurality of teeth. Each of the plurality of orthodontic appliances comprises: an interproximal engagement structure sized to extend across the interproximal space of the teeth from the buccal side of the teeth to the lingual side of the teeth; and one or more tooth receiving structures coupled to the interproximal engagement structures to couple the tooth to one or more other of the plurality of teeth. The position of the interproximal engagement structures relative to one or more tooth receiving structures is varied among the plurality of orthodontic appliances to move teeth from a first position and orientation to a second position and orientation.

In some embodiments, for each of the plurality of appliances, the one or more tooth receiving structures comprise one or more tooth receiving cavities, and the abutment engagement structure is located at a distance from the one or more tooth receiving cavities. The distance varies among the plurality of orthodontic appliances.

In some embodiments, for each of the plurality of appliances, the one or more tooth receiving structures are coupled to the adjacent engagement structure by one or more extensions extending between the adjacent engagement structure and the one or more tooth receiving structures so as to couple the adjacent engagement structure with non-adjacent teeth.

In many embodiments, a method for moving a patient's teeth from a first position and orientation to a second position and orientation is provided. The method includes sequentially providing a plurality of (oral) orthodontic appliances shaped to fit a plurality of teeth, each of the plurality of orthodontic appliances. The plurality of appliances each include a plurality of interproximal engagement structures sized to extend across the interproximal spaces of the teeth from the buccal side of the teeth to the lingual side of the teeth, each of the plurality of engagement structures including an interproximal engagement surface to engage the teeth. Each of the plurality of appliances has a separation distance between the engagement surfaces that varies sequentially among the plurality of appliances to move the teeth from a first position and orientation to a second position and orientation when the plurality of appliances are worn sequentially.

In some embodiments, the separation distance increases sequentially among the plurality of appliances. In some embodiments, the separation distance decreases sequentially among the plurality of appliances.

In some embodiments, for each of the plurality of interproximal engagement structures, the separation distance is sized to receive one or more teeth between the first and second interproximal engagement structures.

In many embodiments, a method for moving a patient's teeth from a first position and orientation to a second position and orientation is provided. The method includes sequentially providing a plurality of orthodontic appliances shaped to fit a plurality of teeth. Each appliance includes a plurality of interproximal engagement structures sized to extend across the interproximal spaces of the teeth a plurality of distances from the buccal side of the teeth to the lingual side of the teeth. The plurality of distances are sequentially decreased in the plurality of appliances to move the teeth from a first position and orientation to a second position and orientation when the plurality of appliances are sequentially worn.

In some embodiments, the plurality of distances are reduced in accordance with movement of the tooth, including one or more of translation or rotation (motion). In some cases, the plurality of distances may decrease in accordance with a translation of one or more teeth; in some cases, the plurality of distances decreases in accordance with a rotation of one or more teeth about a center of rotation.

In some embodiments, the plurality of distances decreases in sequence as a function of sequential rotation of one or more teeth about an axis of rotation passing through the center of rotation of the one or more teeth and the occlusal surface.

In many embodiments, a method for moving a patient's teeth from a first position and orientation to a second position and orientation is provided. An orthodontic shell appliance shaped to fit a plurality of teeth is provided. The shell appliance comprises: an outer wall extending over buccal and lingual surfaces of the plurality of teeth, respectively; and a plurality of interproximal engagement structures sized to extend across the interproximal spaces of the teeth from the buccal side of the teeth to the lingual side of the teeth and coupled to the outer wall on both the buccal and lingual sides of the outer wall. When the appliance is worn, the plurality of interproximal engagement structures urge the buccal and lingual sides of the wall toward each other when disposed over the plurality of teeth.

In some embodiments, the plurality of interproximal engagement structures extend a plurality of distances between the buccal and lingual sides of the wall in a free-standing configuration prior to being positioned, and extend a plurality of respective second distances in a loaded configuration when positioned on the plurality of teeth, the plurality of first distances being less than the plurality of respective second distances. In some embodiments, the wall is shaped to receive one or more teeth, and wherein the wall engages the one or more teeth with a force to move the one or more teeth in response to the force from the interproximal engagement structures.

In many embodiments, a method for moving a patient's teeth from a first position and orientation to a second position and orientation is provided. An orthodontic appliance shaped to fit a plurality of teeth is provided. The appliance comprises: an outer wall extending on buccal and lingual sides of the plurality of teeth when the appliance is worn; and an interproximal engagement structure sized to extend into the interproximal spaces between the teeth and adjacent teeth when the appliance is worn. The interproximal engagement structures extend a distance from the tooth-engaging contact surface to the outer surface of the outer wall when the appliance is worn, the contact surface including a radius of curvature, wherein the radius of curvature is less than one-third of the distance.

In some embodiments, the radius of curvature extends in a bucco-lingual direction to correspond to a curvature of a surface of the tooth in the bucco-lingual direction. In some embodiments, the interproximal engagement structure includes a second contact surface to engage another tooth, the interproximal engagement structure extending a second distance from the second contact surface to the outer surface of the outer wall, the second contact surface including a second radius of curvature, and the second radius of curvature being less than one-third of the second distance.

In some embodiments, the outer surface of the outer wall comprises a buccal surface of the appliance; in some embodiments, the outer surface of the outer wall comprises a lingual surface of the appliance.

In many embodiments, a method for moving a patient's teeth from a first position and orientation to a second position and orientation is provided. The method includes providing a polymeric shell appliance shaped to fit a plurality of teeth. The appliance comprises: an outer wall shaped to extend over exposed buccal, lingual and occlusal surfaces of the plurality of teeth when the appliance is worn; and a plurality of interproximal engagement structures sized to extend into the interproximal spaces of the teeth and couple to the outer wall on the buccal and lingual sides of the outer wall when the appliance is worn. The polymeric shell appliance is configured to contact at least about 60% of a circumferential surface of the plurality of teeth when worn. In some embodiments, the appliance contacts at least about 80% of a circumferential surface of the plurality of teeth when worn.

In many embodiments, a method for moving a patient's teeth from a first position and orientation to a second position and orientation is provided that includes sequentially providing a plurality of orthodontic appliances shaped to fit a plurality of teeth. Each of the plurality of orthodontic appliances comprises: a wall shaped to receive the plurality of teeth; and an interproximal engagement structure extending from the wall. The interproximal engagement structures are sized to fit into the interproximal spaces between adjacent teeth, and the interproximal engagement structures comprise: a length extending from the wall into the interproximal spaces; and a width extending between adjacent teeth in a mesiodistal direction at a position between the adjacent teeth when worn in the patient's mouth. One or more of the length or width of the abutment engagement structure at the above-mentioned locations is varied among the plurality of orthodontic appliances to move the teeth from a first position and orientation to a second position and orientation when the plurality of appliances are worn sequentially.

In some embodiments, each of the interproximal engagement structures includes a contact surface to engage one or more teeth defining the interproximal spaces, and wherein the angle of the contact surface is varied in the plurality of appliances to move the one or more teeth from the first position to the second position. In some embodiments, each interproximal engagement structure includes a contact surface having a length sized to enable the contact surface to engage one or more teeth defining the interproximal spaces, and wherein the length of the contact surface varies among the plurality of appliances to cause a change in the magnitude of the force applied to the one or more teeth. In some embodiments, one or more of the walls or interproximal engagement structures elastically deform or bend in response to forces from the teeth.

In various embodiments, the interproximal engagement structures extend across the interproximal space at the gingival location to a minimum distance between the teeth defining the interproximal space and the adjacent teeth.

In various embodiments, at least one of the appliances comprises a plurality of materials.

In various embodiments, providing an orthodontic appliance includes placing the appliance on a patient's teeth. In various embodiments, the patient places the orthodontic appliance on the teeth.

In various embodiments, the teeth comprise a plurality of teeth.

In various embodiments, the interproximal engagement structures include one or more voids (void).

In many embodiments, a polymeric shell appliance for moving a patient's teeth from a first position and orientation to a second position and orientation is provided. The polymeric shell appliance includes: a polymeric interproximal engagement structure sized to extend across the interproximal spaces of the teeth from the lingual side to the buccal side; and one or more tooth-receiving cavities to couple a tooth to another one or more of the plurality of teeth through another one or more tooth-receiving cavities. The interproximal engagement structures are shaped to apply a force from the interproximal space to the teeth to move the teeth from the first position and orientation to the second position and orientation when the appliance is worn.

In some embodiments, each interproximal engagement structure includes a width extending between adjacent teeth defining the interproximal spaces, wherein the widths sequentially increase in the plurality of appliances such that the distances between the adjacent teeth sequentially increase. In some embodiments, each of the interproximal engagement structures includes opposing contact surfaces to engage adjacent teeth defining the interproximal spaces, and wherein the angles of the contact surfaces with respect to each other are varied in the plurality of appliances to move the teeth from a first position and orientation to a second position and orientation.

In many embodiments, a plurality of orthodontic appliances for moving a patient's teeth from a first position and orientation to a second position and orientation are provided. Each appliance includes: an interproximal engagement structure sized to extend across the interproximal space of the teeth from the buccal side of the teeth to the lingual side of the teeth; and one or more tooth receiving structures coupled to the interproximal engagement structures to couple a tooth to another one or more teeth of the patient. The position of the interproximal engagement structures relative to the one or more tooth-receiving structures is varied among the plurality of orthodontic appliances to move the teeth from a first position and orientation to a second position and orientation when the plurality of appliances are worn in sequence.

In some embodiments, for each of the plurality of appliances, the one or more tooth receiving structures comprise one or more tooth receiving cavities, and the abutment engagement structure is located at a distance from the one or more tooth receiving cavities. The distance varies among the plurality of orthodontic appliances.

In some embodiments, for each of the plurality of appliances, the one or more tooth receiving structures are coupled to the interproximal engagement structures by one or more extensions extending between the interproximal engagement structures and the one or more tooth receiving structures to couple the interproximal engagement structures with non-adjacent teeth.

In many embodiments, a plurality of orthodontic appliances for moving a patient's teeth from a first position and orientation to a second position and orientation are provided. Each appliance includes a plurality of interproximal engagement structures sized to extend across the interproximal spaces of the teeth from the buccal side of the teeth to the lingual side of the teeth, each of the plurality of engagement structures including an interproximal engagement surface to engage the teeth. Each of the plurality of appliances has a separation distance between the engagement surfaces, and the separation distance varies sequentially among the plurality of appliances to move the teeth from a first position and orientation to a second position and orientation when the plurality of appliances are worn sequentially.

In some embodiments, the separation distance increases sequentially among the plurality of appliances; in some embodiments, the separation distance decreases sequentially among the plurality of appliances.

In some embodiments, for each of the plurality of interproximal engagement structures, the separation distance is sized to receive one or more teeth between the first and second interproximal engagement structures.

In many embodiments, a plurality of appliances are provided for moving a patient's teeth from a first position and orientation to a second position and orientation. Each appliance includes a plurality of interproximal engagement structures sized to extend across the interproximal spaces of the teeth from the buccal side of the teeth to the lingual side of the teeth. The plurality of distances are sequentially decreased in the plurality of appliances to move the teeth from a first position and orientation to a second position and orientation when the plurality of appliances are sequentially worn.

In some embodiments, the appliance is configured to produce a movement of the teeth when worn sequentially, the movement including one or more of translation or rotation, and wherein the plurality of distances decrease as a function of the movement of the one or more teeth. In some cases, the appliance is configured to produce a translation of teeth when worn sequentially, and wherein the plurality of distances are decreased as a function of the translation of one or more teeth. In some cases, the appliance is configured to produce rotation of the teeth when worn sequentially, and wherein the plurality of distances decrease according to sequential rotation of one or more teeth about a center of rotation.

In some embodiments, the appliance is configured to produce rotation of the teeth when worn sequentially, wherein the plurality of distances decrease as a function of sequential rotation of the one or more teeth about an axis of rotation passing through the center of rotation of the one or more teeth and the occlusal surface.

In many embodiments, an orthodontic shell appliance for moving a plurality of teeth of a patient from a first position and orientation to a second position and orientation is provided. The appliance comprises: a plurality of tooth receiving cavities; an outer wall coupled to the tooth-receiving cavity and extending over buccal and lingual surfaces of the plurality of teeth, respectively; and a plurality of interproximal engagement structures sized to extend across the respective interproximal spaces from the buccal side of the tooth to the lingual side of the tooth, and coupled to the outer wall on both the buccal and lingual sides of the wall. The plurality of interproximal engagement structures are configured to urge the buccal and lingual sides of the wall toward one another when disposed on the plurality of teeth.

In some embodiments, the plurality of interproximal engagement structures extend a plurality of distances between the buccal and lingual sides of the wall in the free-standing configuration prior to placement, and extend a plurality of respective second distances in the loaded configuration when placed on the plurality of teeth, the plurality of first distances being less than the plurality of respective second distances.

In some embodiments, the wall is shaped to receive one or more teeth and to engage the one or more teeth with a force to move the one or more teeth in response to the force from the abutment engagement structure.

In many embodiments, an orthodontic appliance for moving a patient's teeth from a first position and orientation to a second position and orientation is provided. The appliance comprises: a plurality of tooth receiving cavities; an outer wall coupled to the tooth receiving cavity and extending on buccal and lingual sides of a tooth; and an interproximal engagement structure sized to extend into the interproximal space between the tooth and an adjacent tooth. The abutment engagement structure extends a distance from the tooth-engaging contact surface to the outer surface of the outer wall when the appliance is worn, the contact surface including a radius of curvature, wherein the radius of curvature is less than one third of the distance.

In some embodiments, the radius of curvature extends in a bucco-lingual direction to correspond to a curvature of the tooth surface in the bucco-lingual direction.

In some embodiments, the interproximal engagement structure includes a second contact surface that engages another tooth, wherein the interproximal engagement structure extends a second distance from the second contact surface to the outer surface of the outer wall, the second contact surface including a second radius of curvature, wherein the second radius of curvature is less than one-third of the second distance.

In some embodiments, the outer surface of the outer wall comprises a buccal surface of the appliance; in some embodiments, the outer surface of the outer wall comprises a lingual surface of the appliance.

In many embodiments, a polymeric shell appliance for moving a patient's teeth from a first position and orientation to a second position and orientation is provided. The appliance comprises: a plurality of tooth receiving cavities; an outer wall coupled to the tooth-receiving cavity and extending over exposed buccal, lingual, and occlusal surfaces of the plurality of teeth; and a plurality of interproximal engagement structures sized to extend into the interproximal spaces of the teeth and coupled to the outer wall on the buccal and lingual sides of the wall. The polymeric shell appliance contacts at least about 60% of the circumference of the plurality of teeth. In some embodiments, the polymeric shell appliance contacts at least about 80% of the circumference of the plurality of teeth.

In many embodiments, a plurality of orthodontic appliances for moving a patient's teeth from a first position and orientation to a second position and orientation are provided. Each appliance includes: a wall shaped to receive the plurality of teeth; and an interproximal engagement structure extending from the wall and sized to fit into the interproximal space between adjacent teeth. The interproximal engagement structures comprise: a length extending from the wall into the interproximal spaces; and a width extending between adjacent teeth in a mesial-distal direction at a location between the adjacent teeth. One or more of a length or a width of the abutment engagement structure at the location is varied among the plurality of orthodontic appliances to move the teeth from a first position and orientation to a second position and orientation when the plurality of appliances are worn sequentially.

In some embodiments, each interproximal engagement structure includes a contact surface to engage one or more teeth defining an interproximal space, and wherein the angle of the contact surface is varied in the plurality of appliances to move the one or more teeth from the first position to the second position.

In some embodiments, each interproximal engagement structure includes a contact surface having a length that is sized to engage (cause the contact surface to) one or more teeth defining the interproximal spaces, and wherein the length of the contact surface varies among the plurality of appliances to cause a magnitude of a force applied to the one or more teeth to vary.

In some embodiments, one or more of the walls or adjacent engaging structures comprise the following materials: the material elastically deforms or bends in response to forces from the teeth.

In various embodiments, the interproximal engagement structures extend across the interproximal spaces at the gingival location for a minimum distance between the teeth defining the interproximal spaces and the adjacent teeth.

In various embodiments, at least one of the appliances comprises a plurality of materials. In various embodiments, the orthosis is configured to enable a patient to manually remove it. In various embodiments, the teeth include a plurality of teeth. In various embodiments, the interproximal engagement structures include one or more voids.

In many embodiments, there is provided an appliance for moving one or more teeth from a first position and orientation to a second position and orientation, the appliance comprising: a plurality of interproximal engagement structures engaging the interproximal spaces of the first tooth at a buccal side of the interproximal spaces and a lingual side of the interproximal spaces so as to urge the teeth in a first direction; and an opposing engagement structure urging the teeth in a second direction opposite the first direction to apply a torque to the teeth, the plurality of interproximal engagement structures on the appliance engaging interproximal spaces closer to the gums than the opposing engagement structure.

In many embodiments, there is provided an appliance for moving one or more teeth from a first position and orientation to a second position and orientation, the appliance comprising: an interproximal engagement structure which engages the interproximal spaces of the first teeth to urge the teeth in a first direction; and opposing engagement structures that apply torque to the teeth by urging the teeth in a second direction opposite the first direction, the plurality of interproximal engagement structures on the appliance engaging interproximal spaces closer to the gums than the opposing engagement structures.

In various embodiments, the appliance further includes a plurality of interproximal structures on opposite sides of the second tooth to anchor the appliance to the second tooth while the first tooth is moved.

In some embodiments, the second tooth comprises a plurality of anchor teeth (anchors) and the plurality of interproximal engagement structures comprise pairs of interproximal engagement structures that engage the plurality of anchor teeth. In some embodiments, the interproximal engagement structures comprise a plurality of interproximal engagement structures including a first interproximal engagement structure on the buccal side of the teeth and a second interproximal engagement structure on the lingual side. In some embodiments, the first tooth comprises a plurality of first teeth to be moved and the plurality of interproximal engagement structures comprise pairs of interproximal engagement structures that engage the plurality of first teeth to be moved. In some embodiments, the first tooth comprises a plurality of first teeth to be moved and the interproximal engagement structures comprise a plurality of interproximal engagement structures that engage the plurality of first teeth to be moved.

In various embodiments, the appliance includes a plurality of tooth-receiving cavities shaped to receive teeth and move one or more teeth from a first position and orientation to a second position and orientation.

In various embodiments, moving the one or more teeth includes translation of the one or more teeth. In various embodiments, moving the one or more teeth includes rotation of the one or more teeth. In some embodiments, the rotation comprises rotation about a vertical axis; in some embodiments, the rotation comprises rotation about a bucco-lingual axis.

In various embodiments, the plurality of interproximal engagement structures are combined into a single engagement structure that extends from the buccal side to the lingual side through the interproximal spaces to engage the teeth on both the buccal and lingual sides.

In various embodiments, a method of moving a plurality of teeth with an appliance is provided, including providing an appliance as disclosed herein.

In many embodiments, a method of manufacturing an orthodontic appliance for moving one or more teeth of a patient is provided. A movement path is determined to move one or more teeth from an initial arrangement to a target arrangement. A force system for generating movement of one or more teeth along a movement path is determined. An appliance geometry is determined for an orthodontic appliance configured to generate the force system. An orthodontic appliance is directly manufactured based on the determined appliance geometry.

In some embodiments, the appliance geometry includes at least one interproximal engagement structure configured to engage the interproximal spaces of the first tooth.

In some embodiments, the method further comprises manufacturing a plurality of orthodontic appliances, each of the plurality of orthodontic appliances configured to produce movement along the path of movement.

In various embodiments, the appliances disclosed herein have been manufactured directly.

In some aspects, the direct manufacturing includes additive manufacturing. In some aspects, the direct manufacturing includes subtractive manufacturing.

As used herein, the terms "stiff" and "rigid" are used interchangeably.

As used herein, the terms "torque" and "moment" are considered synonymous.

As used herein, the term "and/or" is used as a functional word to indicate that two words or expressions are used together or separately. For example, A and/or B includes A alone, B alone, and A and B together.

As used herein, "plurality of teeth" includes two or more teeth.

As used herein, "moment" includes a force acting on an object (e.g., a tooth) at a distance from the center of resistance. For example, the moment may be calculated by a vector cross product of vector forces applied to the vector corresponding to the displacement vector of the center of resistance. The moment may include a vector pointing in a certain direction. A moment that is opposite to another moment may comprise, for example, one of the moment vectors oriented toward a first side of the object (e.g., a tooth) and another moment vector oriented toward an opposite side of the object (e.g., a tooth).

As used herein, "differential moment" encompasses two or more moments coupled to each other to provide opposing moments to one or more teeth. The differential torque may include a first torque applied to the teeth and an opposing second torque. Alternatively or in combination, the differential torque may comprise a first torque of one or more first teeth of an arch (arch) coupled to an opposite second torque of one or more second teeth of the arch. One or more first teeth of the arch may comprise a first segment of the arch and one or more second teeth of the arch may comprise a second segment of the arch, wherein a first moment of the first segment of the arch is coupled to an opposite second moment of the second segment of the arch. The one or more first teeth may comprise a plurality of adjacent first teeth of a first segment of an arch and the one or more second teeth may comprise a plurality of adjacent second teeth of a second segment of the arch, wherein a first moment of the plurality of adjacent first teeth of the arch is opposite (opposite) an opposite second moment of the plurality of adjacent second teeth of the arch.

As used herein, a tooth that includes a moment refers to a tooth that: the tooth has a force acting on the tooth about a center of resistance. The force may be generated by an appliance coupled to the teeth either directly, or via attachments to the teeth and a combination of both.

The counter moment described herein can be used to precisely control the movement of one or more teeth and can be used to provide anchoring of one or more teeth. In many embodiments, the plurality of trailing teeth include a counter moment to improve the anchoring of the trailing teeth, and one or more trailing teeth include less counter movement and are moved toward the plurality of anchored trailing teeth. Alternatively, the counter moment of one or more of the plurality of trailing teeth may be configured to allow the one or more trailing teeth to move toward the leading teeth.

The moments of the sets of one or more teeth may be coupled to each other to control the movement of the teeth, and the moments of the sets of one or more teeth may be coupled to each other in a wide variety of ways. The moments of the plurality of sets of one or more teeth may be coupled to each other by an offset moment and/or a balance moment to provide preferential movement to one or more of the plurality of sets of one or more teeth. For example, the rear teeth may be provided with a greater counter torque than the front teeth to move the front teeth toward the rear teeth.

The moments and counter-moments disclosed herein are well suited for moving multiple types of teeth and multiple states of teeth, and for use with multiple states of teeth. For example, embodiments disclosed herein may be used to treat one or more slopes of the occlusal surface (canting), raise teeth on one side of the oral cavity and lower teeth on the opposite side of the oral cavity, expand teeth along the arch, seal the extraction point, intrusion, extrusion, rotation, tilting, and combinations thereof.

In many embodiments, the one or more posterior teeth include one or more of molars, premolars, or canines, and the one or more anterior teeth include one or more of central incisors, lateral incisors, cuspids, first bicuspids, or second bicuspids.

Embodiments disclosed herein may be used to couple groups of one or more teeth to one another. The plurality of sets of one or more teeth may include a first set of one or more front teeth and a second set of one or more rear teeth. The first set of teeth may be coupled to the second set of teeth by a polymeric shell appliance as disclosed herein.

The first set of teeth can be coupled to the second set of teeth in a variety of ways, and in many embodiments, the first set of one or more teeth includes a first moment and a first counter moment, and the second set of one or more teeth includes a second moment and a second counter moment. The first moment and the first counter moment may comprise a combined first moment and a combined first counter moment of the first set of one or more teeth, and the second moment and the second counter moment may comprise a combined second moment and a combined second counter moment of the second set of teeth. The combination of the first moment, the combination of the first counter moment, the combination of the second moment, and the combination of the second counter moment can be coupled to one another by the polymeric shell appliance to move either the first set of one or more teeth or the second set of one or more teeth, and combinations thereof.

In many embodiments, each tooth of the first set of one or more teeth includes a first moment and a counter moment, and each tooth of the second set of one or more teeth includes a second moment and a second counter moment. The first moment may be generated by a first force applied to one or more first teeth at a first region or location of the first teeth, and the counter moment may be generated by a counter force applied to the one first tooth at a reverse location. The second moment may be generated by a second force applied to one or more second teeth at the area of the second tooth, and the counter moment is generated by a counter force applied to this second tooth at the opposite position.

The center of resistance of each tooth may be located, for example, near the bifurcation or three bifurcations in the root of the tooth. For a single tooth, the center of resistance may be located somewhere between about 25% and about 70% of the distance from the alveolar ridge to the apex of the root, for example about 40% of the distance.

The center of resistance of a set of a segment of teeth comprising a plurality of teeth can be determined in one or more of a variety of ways. For example, the center of resistance can be determined by finite element modeling, published values in the scientific literature, bench tests with experimental loads, mathematical formulas and approximations, and various combinations thereof. For example, the center of resistance can be determined based on supporting tooth structures, such as periodontal ligaments, soft tissue, and bone support structures. Although the center of resistance of a set of teeth may vary with direction of movement, one of ordinary skill in the art can determine the center of resistance according to embodiments disclosed herein.

Embodiments disclosed herein are well suited for moving one or more of a first set of one or more teeth, or moving one or more of a second set of one or more teeth, and combinations thereof.

The embodiments disclosed herein are well suited for incorporation with one or more tooth moving parts known and commercially available, such as attachments and polymeric shell appliances. In many embodiments, the appliance and one or more attachments (attachments) are configured to move one or more teeth along a tooth movement vector that includes six degrees of freedom, three of which are rotational degrees of freedom and three of which are translational degrees of freedom. Embodiments disclosed herein may provide a differential moment vector based on the moment and counter-moment for each of a plurality of teeth. The differential moment vector provides more accurate tooth movement and may result in a reduced force for moving one or more teeth.

The present disclosure provides orthodontic systems and related methods that aim to design and provide improved or more effective tooth movement systems to cause desired tooth movement and/or to reposition teeth into a desired arrangement.

Although reference is made to appliances that include a polymer shell appliance, the embodiments disclosed herein are well suited for use with a variety of tooth-receiving appliances, such as appliances that do not have one or more polymers or shells. The orthosis may be made of one or more of a variety of materials such as metal, glass, reinforced fibre, carbon fibre, composite, reinforced composite, aluminium, biomaterial, combinations thereof or the like. The orthosis may be shaped in a number of ways, for example by thermoforming or direct manufacture as disclosed herein. Alternatively or in combination, the orthosis may be manufactured by machining, such as by computer numerical control machining, from a single piece of material.

Orthodontic systems of the present disclosure may include tooth attachments and one or more orthodontic appliances that engage the attachments when worn by a patient. Such an appliance is described generally with reference to fig. 1A: the appliance has tooth receiving cavities that receive and reposition teeth by, for example, applying a force due to the elasticity of the appliance. Fig. 1A illustrates an exemplary tooth repositioning appliance or aligner 100 that can be worn by a patient to achieve incremental repositioning of each tooth 102 in the jaw (jaw). The appliance may include a shell (e.g., a continuous polymeric shell or a segmented shell) having tooth-receiving cavities for receiving and resiliently repositioning the teeth. The appliance, or one or more portions thereof, may be manufactured indirectly using a physical model of the teeth. For example, an appliance (e.g., a polymeric appliance) may be formed using a physical model of a tooth and an appropriate number of layers of polymeric material. In some embodiments, the physical (solid) appliances are fabricated directly from a digital model of the appliance, for example, using rapid prototyping techniques. The appliance can fit over all teeth (or not all teeth) in the upper or lower jaw. The appliance may be specifically designed to accommodate (adapt to) a patient's teeth (e.g., the profile of the tooth-receiving cavity (topograph) matches the profile of the patient's teeth), and may be manufactured based on an impression (impression), scan, etc. generated relief model of the patient's teeth. Alternatively, the appliance may be a universal appliance configured to receive teeth but not necessarily shaped to match the profile of the patient's teeth. In some cases, only some of the teeth received by the appliance may be repositioned by the appliance, while other teeth may provide a base or anchor region to hold the appliance in place when the appliance applies force to the tooth or teeth to be repositioned. In some cases, some or most, or even all, of the teeth will be repositioned during treatmentAt some point. The moved teeth may also serve as a base or anchor to hold the appliance while the appliance is worn by the patient. Typically, no wires or other means will be provided to hold the appliance in place on the teeth. However, in some cases, it may also be desirable or necessary to provide separate attachments or other anchoring elements 104 on the teeth 102 (which fit into corresponding receptacles or holes 106 in the appliance 100) so that the appliance can exert a selected force on the teeth. Numerous patents and patent applications in the name of Alice technologies, Inc., including, for example, U.S. Pat. Nos. 6,450,807 and 5,975,893 and company web pages accessible via the world Wide Web (see, for example, the website "invisal. com"), describe various exemplary appliances, including inThose used in the system. Examples of tooth-mounted attachments suitable for use with orthodontic appliances are also described in patents and patent applications in the name of ericsson corporation, such as U.S. patent nos. 6,309,215 and 6,830,450.

FIG. 1B shows a tooth repositioning system 110 that includes a plurality of appliances 110a, 110B, 110 c. Any of the appliances described herein can be designed and/or provided as part of a set of multiple appliances for use in a tooth repositioning system. Each appliance may be configured such that the tooth-receiving cavities have a geometry corresponding to the intermediate or final tooth arrangement for the appliance. The patient's teeth may be repositioned from the initial tooth arrangement to the target tooth arrangement in steps by placing a series of incremental position adjustment appliances on the patient's teeth. For example, the tooth repositioning system 110 can include a first appliance 110a corresponding to an initial tooth arrangement, one or more intermediate appliances 110b corresponding to one or more intermediate arrangements, and a final appliance 110c corresponding to a target arrangement. The target tooth arrangement may be a final tooth arrangement according to the regimen selected for the patient's teeth at the conclusion of all orthodontic treatments according to the regimen. Alternatively, the target arrangement may be one of some intermediate arrangements for the patient's teeth during the orthodontic treatment process, which may include a variety of different treatment options, including (but not limited to) the following: surgery is recommended, adjacent enamel removal (IPR) is appropriate, scheduling is scheduled, anchor placement is best, palatal expansion is desirable, dentistry is involved with restorations (e.g., inlays, onlays, crowns, bridges, implants, patches, etc.), and the like. Likewise, it should be understood that the target tooth arrangement may be any resulting arrangement for a patient's teeth according to a protocol that follows one or more incremental repositioning stages. Likewise, the initial tooth arrangement may be any initial arrangement for a patient's teeth followed by one or more incremental repositioning stages.

Fig. 1C illustrates a method 150 of orthodontic treatment using multiple appliances, according to an embodiment. The method 150 may be implemented using any of the appliances or appliance groups described herein. In step 160, a first orthodontic appliance is applied to the patient's teeth to reposition the teeth from the first tooth arrangement to the second tooth arrangement. In step 170, a second orthodontic appliance is applied to the patient's teeth to reposition the second tooth arrangement to a third tooth arrangement. The method 150 can be repeated (using any suitable combination of numbers and successive appliances) as necessary to incrementally reposition the patient's teeth from the initial arrangement to the target arrangement. These appliances may all be produced at the same stage, either in sets or in batches (e.g., at the beginning of a treatment stage), or one appliance at a time may be manufactured and the patient may wear each appliance until the pressure of each appliance on the teeth may no longer be felt, or until the maximum amount of tooth movement specified for a given stage has been achieved. A plurality of different (e.g., a set of) appliances may be designed or even manufactured before a patient wears any of the appliances. After wearing the appliance for an appropriate period, the patient may replace the current appliance with the next appliance in the series until there are no more subsequent appliances. These appliances are typically not fixedly attached to the teeth, and the patient can place and reposition the appliance (e.g., an appliance that can be removed by the patient) at any time during the course of treatment. The several appliances or final appliances in the series may have one or more geometries selected for overcorrected tooth alignment. For example, one or more of the appliances may have a geometry that will cause (if achieved at all) individual teeth to move beyond the arrangement of teeth that has been selected as the "final" plan. Such overcorrection (no-post) may be suitable to compensate for possible recurrence after the repositioning process has terminated (e.g., allowing each tooth to move back toward its pre-corrected position). Overcorrection may also be beneficial to accelerate the rate of correction (e.g., an appliance with a geometry positioned beyond a desired intermediate or final position may displace individual teeth toward that position at a greater rate). In such cases, the use of the appliance may be terminated before the teeth reach the positions defined by the appliance. Furthermore, over-correction can be intentionally made to compensate for any error or limitation of the appliance.

The various embodiments of the orthodontic appliances described herein can be made in a number of different ways. In some embodiments, the orthodontic appliances herein (or portions thereof) can be produced using direct manufacturing, such as additive manufacturing techniques (also referred to herein as "3D printing") or subtractive manufacturing techniques (e.g., milling), and the like. In some embodiments, direct fabrication includes forming an object (e.g., an orthodontic appliance or portions thereof) without using physical templates (e.g., molds, masks, etc.) to define the object geometry. Additive manufacturing techniques can be classified as follows: (1) slot photocuring (e.g., stereolithography), in which an object is built layer by layer from a slot of liquid photopolymer resin; (2) material jetting, wherein the material is jetted onto the build platform using a continuous or Drop On Demand (DOD) method; (3) adhesive jetting, wherein alternating multiple layers of build material (e.g., powder-based material) and bonding material (e.g., liquid adhesive) are deposited by a printhead; (4) fused Deposition Modeling (FDM), in which material is drawn through a nozzle, heated, and deposited layer by layer; (5) powder bed fusion including, but not limited to, Direct Metal Laser Sintering (DMLS), Electron Beam Melting (EBM), Selective Heat Sintering (SHS), Selective Laser Melting (SLM), and Selective Laser Sintering (SLS); (6) sheet lamination, including but not limited to Layered Object Manufacturing (LOM) and Ultrasonic Additive Manufacturing (UAM); and (7) directed energy deposition including, but not limited to, laser engineering net shape, directed light fabrication, direct metal deposition, and 3D laser cladding. For example, stereolithography can be used to directly fabricate one or more of the appliances herein. In some embodiments, stereolithography involves selective polymerization of a photosensitive resin (e.g., photopolymer) using light (e.g., ultraviolet light) according to a desired cross-sectional shape. The object geometry can be built layer by sequentially polymerizing a plurality of object cross sections. As another example, the appliances herein can be directly manufactured using selective laser sintering. In some embodiments, selective laser sintering includes selectively melting and fusing layers of powder material using a laser beam according to a desired cross-sectional shape in order to build object geometry. As yet another example, the appliances herein may be directly manufactured by fused deposition modeling. In some embodiments, fused deposition modeling includes melting and selectively depositing filaments (fibers) of thermoplastic polymer in a layer-by-layer manner to form an object. In yet another example, the appliances herein can be directly manufactured using material injection. In some embodiments, material jetting includes jetting or extruding one or more materials onto the build surface to form a continuous layer of the object geometry.

Alternatively or in combination, some embodiments of the appliances herein (or portions thereof) can be produced using indirect manufacturing techniques, such as by thermoforming over a male-female mold. Indirect manufacturing of an orthodontic appliance may include producing a concave-convex mold of a patient's dentition (e.g., by rapid prototyping, milling, etc.) in accordance with the target arrangement and thermoforming one or more pieces of material onto the mold to form the appliance shell.

In some embodiments, the direct fabrication methods provided herein build object geometry in a layer-by-layer manner, and form continuous layers through discrete build steps. Alternatively or in combination, a direct manufacturing method (also referred to herein as "continuous direct manufacturing") may be used that allows for continuous building of the object geometry. Various types of continuous direct manufacturing processes can be used. As one example, in certain embodiments, the appliances herein are manufactured using "continuous liquid phase intermediate printing" in which objects are continuously built from a storage container of photopolymerizable resin by forming a gradient of partially cured resin between the build surface of the object and a "dead zone" that inhibits polymerization. In some embodiments, a semi-permeable membrane is used to control the transfer of a photopolymerization inhibitor (e.g., oxygen) into the dead zone so as to form a polymer gradient. Continuous liquid phase intermediate printing can achieve about 25 to about 100 times faster manufacturing speeds than other direct manufacturing methods, and about 1000 times faster speeds can be achieved by incorporating a cooling system. Continuous liquid phase intermediate printing is described in U.S. patent publication nos. 2015/0097315, 2015/0097316, and 2015/0102532, the disclosures of each of which are incorporated herein by reference in their entirety.

As another example, a continuous direct manufacturing method may achieve a continuous build of the object geometry by a continuous movement of the build platform during the illumination phase (e.g. along the vertical or Z direction) such that the hardening depth of the illuminated photopolymer is controlled by the speed of the movement. Thus, continuous polymerization of the material on the build surface can be achieved. Such a method is described in U.S. Pat. No. 7,892,474, the disclosure of which is incorporated herein by reference in its entirety.

In another example, a continuous direct manufacturing method may include extruding a composite material composed of a curable liquid material around a solid wire. The composite material may be extruded along a continuous three-dimensional path to form an object. Such a method is described in U.S. patent publication No. 2014/0061974, the disclosure of which is incorporated herein by reference in its entirety.

In yet another example, the continuous direct fabrication method utilizes a "helicoidal lithography" method, in which a liquid photopolymer is cured under focused illumination while the build platform is continuously rotated and raised. Thus, the object geometry may be built continuously along a spiral build path. Such a method is described in U.S. patent publication No. 2014/0265034, the disclosure of which is incorporated herein by reference in its entirety.

The direct fabrication methods provided herein are compatible with a wide variety of different materials, including but not limited to one or more of the following: polyesters, copolyesters, polycarbonates, thermoplastic polyurethanes, polypropylenes, polyethylenes, polypropylene and polyethylene copolymers, acrylics, cyclic block copolymers, polyetheretherketones, polyamides, polyethylene terephthalate, polybutylene terephthalate, polyetherimides, polyethersulfones, polytrimethylene terephthalate, Styrene Block Copolymers (SBCs), silicone rubbers, elastomer alloys, thermoplastic elastomers (TPEs), thermoplastic vulcanizate (TPV) elastomers, polyurethane elastomers, block copolymer elastomers, polyolefin blend elastomers, thermoplastic copolyester elastomers, thermoplastic polyamide elastomers, or combinations thereof. The materials used for direct fabrication can be provided in uncured form (e.g., as a liquid, resin, powder, etc.) and can be cured (e.g., by photopolymerization, photocuring, gas curing, laser curing, crosslinking, etc.) to form the orthodontic appliance or a portion thereof. The properties of the material before curing may be different from the properties of the material after curing. Once cured, the materials herein can exhibit sufficient properties utilized in orthodontic appliances such as strength, stiffness, durability, biocompatibility, and the like. The post-cure properties of the material used may be selected according to the desired properties of the corresponding portion of the appliance.

In some embodiments, the relatively stiff portion of the orthodontic appliance may be formed by direct fabrication using one or more of the following materials: polyesters, copolyesters, polycarbonates, thermoplastic polyurethanes, polypropylenes, polyethylenes, polypropylene and polyethylene copolymers, acrylics, cyclic block copolymers, polyetheretherketones, polyamides, polyethylene terephthalate, polybutylene terephthalate, polyetherimides, polyethersulfones, and/or polytrimethylene terephthalate.

In some embodiments, the relatively elastic portion of the orthodontic appliance may be formed by direct fabrication using one or more of the following materials: styrene Block Copolymers (SBC), silicone rubbers, elastomer alloys, thermoplastic elastomers (TPE), thermoplastic vulcanizate (TPV) elastomers, polyurethane elastomers, block copolymer elastomers, polyolefin blend elastomers, thermoplastic copolyester elastomers and/or thermoplastic polyamide elastomers.

The machine parameters may include curing parameters. For Digital Light Processing (DLP) based curing systems, the curing parameters may include power, curing time, and/or grayscale of the complete image. For laser-based curing systems, the curing parameters may include power, speed, beam size, beam shape, and/or power distribution of the beam. For printing systems, the curing parameters may include drop size, viscosity, and/or curing power of the material. These machine parameters may be monitored and adjusted periodically as part of process control on the manufacturing machine (e.g., some parameters at every 1-x layer and some parameters after each build). Process control can be achieved by placing sensors on the machine that measure power and other beam parameters per layer or every few seconds and automatically adjust them through a feedback loop. For DLP machines, the gray scale may be measured and calibrated before, during, and/or at the end of each build, and/or at predetermined time intervals (e.g., every nth build, once per hour, once per day, once per week, etc.), depending on the stability of the system. Further, material properties and/or optical properties may be provided to the manufacturing machine, and the machine process control module may use these parameters to adjust machine parameters (e.g., power, time, grayscale, etc.) to compensate for variability in the material properties. By implementing process control on the manufacturing machine, variability in appliance accuracy and residual stress can be reduced.

Alternatively, the direct manufacturing methods described herein enable the manufacture of appliances comprising multiple materials, referred to herein as "multi-material direct manufacturing. In some embodiments, a multi-material direct fabrication method includes forming an object from multiple materials simultaneously in a single fabrication step. For example, a multi-tip extrusion device may be used to selectively dispense multiple types of materials (e.g., resins, liquids, solids, or combinations thereof) from different material supplies to fabricate objects from multiple different materials. Such a process is described in U.S. patent No. 6,749,414, the disclosure of which is incorporated herein by reference in its entirety. Alternatively or in combination, the multi-material direct manufacturing method may comprise forming the object from a plurality of materials in a plurality of consecutive manufacturing steps. For example, a first portion of an object (e.g., an appliance shell) can be formed from a first material according to any of the direct manufacturing methods herein, then a second portion of the object (e.g., one or more elastics) can be formed from a second material according to the methods herein, and so on until the entire object is formed. The relative arrangement of the first and second portions may be varied as desired, for example, the first portion of the object may be wholly or partially sealed by the second portion.

Direct fabrication may provide a number of advantages over other fabrication methods. For example, direct manufacturing, as opposed to indirect manufacturing, allows the orthodontic appliance to be produced without the use of any molds or templates for shaping the appliance, thereby reducing the number of manufacturing steps involved and improving the resolution and accuracy of the final appliance geometry. Furthermore, direct fabrication allows for precise control of the three-dimensional geometry of the appliance, such as appliance thickness. The complex structures and/or auxiliary components may be integrally formed as a single piece with the appliance shell in a single manufacturing step, rather than being added to the shell in a separate manufacturing step. In some embodiments, direct manufacturing is used to create an appliance geometry that would be difficult to create using other manufacturing techniques, such as appliances with very small or fine features, complex geometries, undercuts, interproximal structures, shells of variable thickness, and/or internal structures (e.g., to increase strength by reducing weight and material usage). For example, in some embodiments, the direct manufacturing methods herein allow for the manufacture of orthodontic appliances having a plurality of feature sizes less than or equal to about 5 μm, or ranging from about 5 μm to about 50 μm, or ranging from about 20 μm to about 50 μm.

The direct fabrication techniques described herein may be used to produce appliances having substantially isotropic material properties, e.g., substantially the same or similar strength in all directions. In some embodiments, the direct manufacturing methods herein allow for the production of orthodontic appliances having an intensity variation along all directions of no more than about 25%, about 20%, about 15%, about 10%, about 5%, about 1%, or about 0.5%. Further, the direct manufacturing methods herein can be used to produce orthodontic appliances at a faster rate than other manufacturing techniques. In some embodiments, the direct manufacturing methods herein allow for the production of orthodontic appliances at time intervals of less than or equal to about 1 hour, about 30 minutes, about 25 minutes, about 20 minutes, about 15 minutes, about 10 minutes, about 5 minutes, about 4 minutes, about 3 minutes, about 2 minutes, about 1 minute, or about 30 seconds. Such manufacturing speeds allow for rapid "at the clinic chair" production of custom appliances, for example, during routine appointments or health checks.

In some embodiments, the direct manufacturing methods described herein implement process control for various machine parameters of the direct manufacturing system or device, thereby ensuring that the resulting appliance is manufactured with high precision. Such precision may be beneficial to ensure that the required force system is accurately transferred to the teeth in order to effectively cause tooth movement. Process control may be implemented to account for process variability caused by a variety of sources, such as material properties, machine parameters, environmental variables, and/or post-processing parameters.

The material properties may vary based on the properties of the raw materials, the purity of the raw materials, and/or process variables during the raw material mix. In many embodiments, resins or other materials used for direct fabrication should be fabricated under tight process control to ensure little variability in optical properties, material properties (e.g., viscosity, surface tension), physical properties (e.g., modulus, strength, elongation), and/or thermal properties (e.g., glass transition temperature, heat distortion temperature). Process control for the material manufacturing process may be achieved by screening of raw material physical properties and/or control of temperature, humidity and/or other process parameters during the mixing process. By implementing process control over the material manufacturing process, variability in process parameters may be reduced and material properties may be more uniform from batch to batch. As discussed further herein, residual variability in material properties can be compensated for by on-machine process control.

The machine parameters may include curing parameters. For Digital Light Processing (DLP) based curing systems, the curing parameters may include power, curing time, and/or grayscale of the complete image. For laser-based curing systems, the curing parameters may include power, speed, beam size, beam shape, and/or power distribution of the beam. For printing systems, the curing parameters may include drop size, viscosity, and/or curing power. These machine parameters may be monitored and adjusted periodically as part of process control on the manufacturing machine (e.g., some parameters at every 1-x layer and some parameters after each build). Process control can be achieved by placing sensors on the machine that measure power and other beam parameters per layer or every few seconds and automatically adjust them through a feedback loop. For DLP machines, the gray scale can be measured and calibrated at the end of each build. Furthermore, material properties and/or optical properties may be provided to the manufacturing machine, and the machine process control module may use these parameters to adjust machine parameters (e.g., power, time, grayscale, etc.) to compensate for variability in material properties. By implementing process control on the manufacturing machine, variability in appliance accuracy and variability in residual stress can be reduced.

In many embodiments, environmental variables (e.g., temperature, humidity, sunlight, or exposure to other energy/curing sources) are kept within small ranges to reduce variability in appliance thickness and/or other properties. Optionally, the machine parameters may be adjusted to compensate for environmental variables.

In many embodiments, post-processing of the appliance includes cleaning, post-curing, and/or buttress removal processes. Relevant post-processing parameters may include purity of the cleaning agent, cleaning pressure and/or temperature, cleaning time, post-cure energy and/or time, and/or stability of the support removal process. These parameters may be measured and adjusted as part of a process control scheme. In addition, the physical properties of the appliance may be altered by modifying the post-processing parameters. Adjusting post-processing machine parameters can provide another way to compensate for variability in material properties and/or machine properties.

The configuration of the orthodontic appliances herein can be determined according to the patient's treatment regimen, such as a treatment regimen that includes the continuous management of multiple appliances for incrementally repositioning teeth. Computer-based treatment protocols and/or appliance manufacturing methods may be used to facilitate the design and manufacture of appliances. For example, one or more appliance components described herein may be digitally designed and manufactured by means of computer controlled manufacturing equipment (e.g., Computer Numerical Control (CNC) milling, computer controlled prototyping such as 3D printing, etc.). The computer-based methods described herein may improve the accuracy, flexibility, and convenience of appliance manufacture.

An orthodontic appliance (as shown in fig. 1A) applies a force to the crown of a tooth and/or an attachment positioned on the tooth at each point of contact between the tooth receiving cavity of the appliance and the received tooth and/or attachment. The magnitude of each of these forces and their distribution over the tooth surface determine the type of orthodontic tooth movement that is caused. The types of tooth movement are generally described as extrusion, intrusion, rotation, tilting, translation, and root movement. Tooth movement of the crown greater than tooth root movement is called tilting (tipping). The equal-scale movement of crowns and roots is called translation. The movement of the dedendum greater than the movement of the crown is referred to as dedendum movement.

Tooth movement may be in either direction in either plane of space and may include one or more of rotation or translation along one or more axes.

Fig. 2 illustrates the components of the orthotic device 100 and the corresponding forces. The orthotic device 100 may include one or more polymeric shell appliances constructed and arranged to provide tooth movement forces as described herein. Each tooth of the plurality of teeth 10 includes a root 12 and a crown 14, and the polymeric appliance may apply a force to the crown on the crown to move each tooth. The force applied in this manner may be combined with, or alternatively applied to, or in addition to, the force that may be applied through the action of the polymer shell on the tooth attachment, as disclosed in provisional patent No. 62/099,965, which is incorporated herein by reference in its entirety. Each tooth of the plurality of teeth is movable relative to the center of resistance.

The plurality of teeth 10 may comprise two or more of any teeth in the oral cavity. The plurality of teeth 10 may include one or more of a plurality of posterior teeth 20, such as a plurality of molars or bicuspids, and combinations thereof. For example, the plurality of posterior teeth 20 may include one or more of bicuspids 26, first molars 24, or second molars 22. The plurality of posterior teeth may comprise third molars, including, for example, wisdom teeth. Alternatively or in combination, the plurality of teeth 10 may include one or more of the plurality of front teeth 30. For example, the plurality of anterior teeth may include one or more of bicuspids, canine teeth, or incisors teeth. In many embodiments, the plurality of anterior teeth 30 includes cuspid teeth 32, (canine teeth) and one or more adjacent incisor teeth, such as incisor teeth 34 and incisor teeth 36.

Many of the embodiments disclosed herein are particularly useful for closing an extraction point, such as the extraction point between the rear teeth 20 and the front teeth 30. In many embodiments, one or more teeth are moved to fill the extraction point by movement in the target direction 105. Although target direction 105 can extend in either direction, in many embodiments, target direction 105 extends in the direction of the arrow (e.g., in the mesial-distal direction). The amount of tilt and/or counter-rotation can be controlled by the size and shape of the appliance, the engagement structure of the appliance, and thus the teeth are moved directly with the appropriate force.

In many embodiments, each tooth includes a center of resistance relative to a force applied to the tooth, and the tooth is rotatable about the center of resistance, or substantially rotatable about the center of resistance in three-dimensional space. The first molar 24 may include centers of resistance 25 located near the three prongs of the root. The second molars 22 may include centers of resistance 23 located near the three prongs of the root. For example, the dual cuspid 26 may include a center of resistance 27. Cuspid teeth 32 may include a center of resistance 33. The incisors 34 and 36 may each include a center of resistance. The location of the centers of resistance of the plurality of teeth described herein can correspond to centers of resistance known to one of ordinary skill in the art.

Applying a force to the tooth to move the tooth can create a moment about the center of the resistance on the tooth. In many embodiments, the targeted tooth to be moved (e.g., cuspid 32) receives a force from the polymeric shell appliance, which may be a force directly from the inner surface of the shell or an indirect force through an attachment, and combinations thereof. The direct fabrication of the polymeric shell allows for the formation of interproximal tooth engaging structures on the shell such that the engaging structures contact the teeth at the interproximal engagement locations 140 when worn. Depending on the size of the interproximal spaces (e.g., between teeth 32 and 34), the interproximal tooth engaging structures may pass through the interproximal region, or the interproximal tooth engaging structures may include more than one structure, which are located in similar positions on the lingual and buccal sides of the interproximal spaces, respectively.

The use of direct manufacturing techniques allows the interproximal structures to be formed as structures that extend across the interproximal gap from the lingual side to the buccal side, such structures being able to have thicknesses much less than is possible using prior art techniques (e.g., thermoforming). For example, the interproximal engagement structures may be manufactured to have a thickness of about 0.75mm or less, about 0.45mm or less, about 0.20mm or less, about 0.10mm or less, about 0.07mm or less, or even about 0.05mm or less at their narrowest point to allow the structures to pass through relatively small interproximal gaps. Any of a number of different materials may be used to form such a structure depending on the force required; for example, when a force is applied over a distance to move a tooth, the abutment engagement structure may comprise an elastomeric material, while when the force required is greater, the abutment engagement structure may comprise a stiff material. The material may be matched or dissimilar to the material of the appliance shell, depending on the manufacturing technique chosen.

The interproximal engagement structures may also be shaped to vary in thickness to match the shape of the interproximal spaces, narrowing at their narrowest points and remaining thicker in thickness elsewhere. The contact surfaces of the interproximal engagement structures may be shaped to conform to the shape of the engaged teeth to enable a wide distribution of applied forces. In some cases, the interproximal spaces may be initially too small, but are enlarged during treatment to allow the interproximal engagement structures to pass from the lingual side to the buccal side. For example, a first appliance may be manufactured with the interproximal engagement structures on one or both sides of the interproximal gap to apply force when the gap is extremely narrow, while a second appliance may be manufactured with the interproximal engagement structures across the interproximal gap once the interproximal gap is widened, allowing force to be applied across the interproximal tooth surfaces. Conversely, a reverse process may also be performed in which the interproximal gaps are narrowed, with the first interproximal engagement structures passing through the gaps and the second structures extending into the gaps, and not passing through the gaps once narrowed.

The engagement position 140 can be changed to contact the tooth 32 in order to guide the tooth 32 through the planned movement. Engagement of the teeth 32 with the engagement structure of the polymeric shell appliance 11 at location 140 can result in a force vector acting on the teeth at location 140, as indicated by arrow 141. The shape and location of the engagement structure at location 140 may be selected to customize (customize, set as desired) the location, magnitude, and distribution of force 141. As the teeth 32 resist through the center of resistance 33, a moment 146 about the center of resistance is available. The torque 146 can cause rotation 32 of the tooth.

In many embodiments, a force may be applied to the teeth to generate a counter moment, providing movement of the teeth by a differential moment between the first moment and the second moment. The counter moment 136 may be provided by a tooth engaging structure made on the polymeric shell appliance 11 to contact the teeth at a location 130 located near the bite of the teeth. Alternatively or additionally, the attachments on the teeth may be engaged by contacting the polymeric shell appliance 11. Contact of the engaging structure with the tooth at location 130 produces a force vector as shown by arrow 131 that opposes the force vector at location 140 as shown by arrow 141. The shape and location of the engagement structure at location 130 may be selected to customize the location, magnitude, and distribution of force 131.

In many embodiments, the location selected to produce the counter moment is located further from the center of resistance than from the junction of the attachment or the crown surface that urges the target tooth in the target direction such that the force vector in the target direction is greater than the counter force in the opposite direction so as to produce the differential moment and urge the target tooth in the target direction. In many embodiments, the engagement structure contacting the tooth at the location 140 where the tooth 32 is urged in the target direction 105 is closer to the center of resistance 33 and the gum than the counter force location 130, such that the counter moment 136 can be approximated by the moment 146 to control the rotation of the tooth 32 as the tooth moves in the target direction 105. For example, counter moment 136 may be less than moment 146 to allow the tooth to tilt with rotation in target direction 105, may be greater than moment 146 to rotate the crown in a direction away from target direction 105, or may be similar to moment 146 to maintain the orientation of tooth 32 as the tooth moves in target direction 105. In many embodiments, the appliance 11 comprising a polymeric shell includes an engagement structure to engage the teeth or to engage attachments on the teeth, and the engagement structure can be positioned and shaped to provide a counter force of a suitable magnitude to provide a counter moment to guide the teeth along the target path.

In many embodiments, for example, moment 136 opposes moment 116, moment 117, and moment 118. Moments 116, 117, and 188 are oriented in the same direction as shown. According to the right hand three coordinate system, moment 136 will be oriented toward one side of the plurality of teeth (out of the page toward the viewing position), while moment 116, moment 117, and moment 118 will be oriented in the same direction (in from the page away from the viewer) from moment 136 toward the opposite side of the teeth. For example, moment 136 may be oriented toward the buccal side of the set of teeth, while moment 116, moment 117, and moment 118 may be oriented in the same direction toward the lingual side of the set of teeth.

In many embodiments, the force and counter force on the teeth can be induced by fabricating a polymeric shell, wherein the engaging structure has an equilibrium position that is different from the position the engaging structure is in when engaged with the teeth. For example, the appliance may be manufactured so that the bite and abutment engagement structures have equilibrium positions corresponding to positions 132 and 142, respectively, but are biased to positions 130 and 140 by contact with the teeth when the appliance is worn by the patient. In some embodiments, the offset of the engagement structure from the equilibrium position can be achieved by using a variety of materials, wherein the engagement structure can comprise a rigid polymeric material and a portion of the polymeric shell appliance connecting the two structures can comprise a resilient polymeric material. The potential energy provided by the elastic polymer material may thus be used to generate the force 141 and the counter force 131 as the engagement structure is displaced from its equilibrium position. The amount, direction, location and distribution of force on each surface of the teeth can be independently tailored through the selection of the polymeric material, the engagement structure and the shape and location of the portion of the polymeric shell appliance 11 that connects the structures.

One or more of the plurality of trailing teeth 20 may be configured by differential torque to control the orientation of one or more teeth. In many embodiments, the counter moment of the rear teeth is configured to resist movement of the rear teeth. The work associated with these examples shows that rotating the crown of a tooth away from the force used to move the adjacent tooth can resist movement of the tooth; and rotation of the crown of a tooth toward a force from an adjacent tooth can facilitate movement of the tooth toward the adjacent tooth. In many embodiments, the plurality of posterior teeth 20 include a series of adjacent teeth that are configured to anchor the appliance and move the targeted tooth with little or no movement of the plurality of adjacent anchor teeth. Alternatively or in combination, one or more of the plurality of posterior teeth 20 may be configured to move, for example, toward a target tooth.

In many embodiments, a large differential torque is provided between a set of one or more trailing teeth and a set of one or more leading teeth in order to anchor the trailing teeth. The counter moment of the rear teeth may be greater than the counter moment of the front teeth in order to anchor the rear teeth, e.g. to provide the maximum anchoring force to the rear teeth.

In many embodiments, differential moments are provided between groups of teeth as described herein to provide greater control over tooth movement. In many embodiments, the first set of teeth includes a first moment and the second set of teeth includes a second moment, and a differential moment between the first moment of the first set of teeth and the second moment of the second set of teeth enables selective movement of the front teeth and the rear teeth.

The polymeric shell appliances may be configured to couple the plurality of sets of one or more teeth to one another in a variety of ways. For example, a first set of one or more teeth may be coupled to a second set of one or more teeth. In many embodiments, the first set of one or more teeth comprises a plurality of first teeth, and the polymeric shell appliance comprises a shape to generate a first counter moment on each of a plurality of adjacent first teeth, wherein the first counter moment comprises a combination of moments from each of the plurality of adjacent first teeth oriented in the same direction, as illustrated and described herein (e.g., with reference to fig. 2). The second set of one or more teeth may comprise a plurality of second teeth, and the polymeric shell appliance may comprise a shape to generate a second counter moment on each of a plurality of adjacent second teeth, wherein the second counter moment comprises a combination of moments from each of the plurality of adjacent second teeth oriented in the same direction.

In many embodiments, teeth that contain moments include teeth that have a force applied from the appliance to produce a moment or counter moment about the center of the resistance force. A set of teeth that contain moments or counter-moments may include an appliance that engages one or more of the teeth to provide a moment or counter-moment about a center of resistance.

In many embodiments, the plurality of tooth-receiving cavities are shaped and configured to balance differential moments between the one or more first teeth and the one or more second teeth via polymeric appliances extending between the first set of one or more teeth and the second set of one or more teeth. Alternatively or in combination, the plurality of tooth-receiving cavities may be shaped and arranged to balance first and second counter moments between one or more first teeth and one or more second teeth.

In many embodiments, the majority of the posterior teeth include a generally exposed surface 16 that is adapted to engage a polymeric appliance. The polymeric shell appliance 11 may generate a force along the back surface of the crown at the juncture, as indicated by arrow 122. Alternatively or additionally, the interproximal tooth engaging structures may be fabricated to engage the teeth at one or more interproximal locations 123 to provide the interproximal force 124. The forward directed force, as indicated by arrow 122 and/or arrow 124, produces a moment 126, for example, about the center of resistance 23 of the second molar tooth 22. In many embodiments, the forces of the appliance, as indicated by arrows 122 and/or arrows 124, produce a moment 127 about the center of resistance 25 of the first molar tooth 24, and a moment 128 about the center of resistance 27 of the bicuspid tooth 26, for example. One or more of the plurality of trailing teeth may contact the plurality of engagement structures at locations such as 110, 112, or 114 to generate a counter moment. Alternatively, since the effect of the moments 126, 127, and 128 is relatively small, the structures that cause these counter moments may be omitted.

In many embodiments, a counter moment is provided for a set of one or more teeth (e.g., for a plurality of posterior teeth). The counter moment may comprise a sum of the counter moments of each tooth of the set of teeth. The combined counter moment may include a counter moment about a combined center of resistance that is remote from a center of resistance of each tooth of the set of teeth. One of ordinary skill in the art can determine the center of resistance for a set of teeth by one or more known means and in accordance with the embodiments disclosed herein.

Contact of the tooth engaging structure with the tooth at location 110 can produce a counter force, as indicated by arrow 111, which opposes the force, as indicated by arrow 122, to produce a counter moment 116. The counter moment 116 may be greater than the moment 126 such that the crown of the second molar 22 rotates away from the first molar 24 with, for example, a differential moment resulting from the sum of the moment 126 and the counter moment 116. Alternatively, the counter moment 116 may be less than the moment 126 and also prevent rotation of the second molar 22 toward the first molar 24.

The moment and counter moment of each tooth can be determined based on the magnitude of the force applied to that tooth and the distance from the center of resistance to the location of the force along the elongated axis of the tooth. The force indicated by arrow 122 is applied at a distance 160 from the center of resistance 23 along the elongated axial line of the tooth. The counter moment indicated by arrow 111 is applied at a distance 162 from the center of resistance 23. In many embodiments, moment 126 is approximately equal to distance 160 multiplied by the force indicated by arrow 122. Counter moment 112 is approximately equal to the product of distance 162 and the counter force on attachment 110 shown by arrow 111. One of ordinary skill in the art will recognize that the moments described herein may be determined in a number of ways, such as finite element modeling and integrating multiple moments at multiple locations along the tooth relative to the center of resistance.

Contact between the tooth engaging structure and the tooth at location 112 may produce a counter force as shown by arrow 113 that opposes the force shown by arrow 122 to produce a counter moment 117. The counter moment 117 may be greater than the moment 127 such that the crown of the first molar 24 rotates away from the bicuspid 26, for example, by a differential moment resulting from the sum of the moment 127 and the counter moment 117. Alternatively, the counter moment 117 may be less than the moment 127 and also prevent rotation of the first molar tooth 24 toward the bicuspid tooth 26.

Contact between the tooth engaging structure and the tooth at location 114 can produce a counter force as shown by arrow 115 opposite the force shown by arrow 122 to produce a counter moment 118. The counter moment 118 may be greater than the moment 128 such that the crown of the bicuspid 26 rotates away from the target tooth including the cuspid 32, e.g., via a differential moment resulting from the sum of the moment 128 and the counter moment 118. Alternatively, counter-torque 118 may be less than torque 128 and also resist rotation of dual cuspids 26 toward the target tooth including cuspid 32.

Although described with reference to a plurality of rear teeth as anchors (anchoring blocks) having a counter moment, in many embodiments, the plurality of rear teeth may be configured as anchors that: it has no counter rotation and counter moment and no attachment to move one or more target teeth through a polymer shell coupled to the plurality of posterior teeth and the one or more target teeth.

In many embodiments, movement of one or more teeth along the target vector may cause movement of one or more adjacent teeth. In many embodiments, movement of cuspid teeth 32 toward the extraction point may cause extrusion of one or more adjacent incisors (e.g., incisors 34 and incisors 36). In many embodiments, the polymeric shell appliance 11 is configured to provide one or more actuating forces to one or more teeth. The polymeric shell appliance 11 may be configured to apply an actuation force 150 to the incisors 34 via actuation of the polymeric shell. In many embodiments, the actuation force 150 is not sufficient to hard squeeze the incisors 34 with the incisors 34 at the target location, and the actuation force 150 is sufficient to resist the squeezing out of the incisors 34. The extrusion of the incisors 34 and the movement of the cuspids 32 may result in increased deflection of the appliance 11 and increased actuation force 150 to resist further extrusion of the incisors 34. Similarly, the polymer shell appliance may apply an actuation force 152 and a moment 154 to the incisors 36 to resist extrusion and tilting of the incisors 36.

Fig. 2 illustrates a method 200 for designing an orthodontic appliance produced by direct manufacturing, according to an embodiment. The method 200 may be applied to any embodiment of the orthodontic appliance described herein. Some or all of the steps of method 200 may be performed by any suitable data processing system or device (e.g., one or more processors configured with suitable instructions).

In step 210, a movement path for moving one or more teeth from the initial arrangement to the target arrangement is determined. The initial alignment may be determined from a mold or scan of the patient's teeth or oral tissue (e.g., using wax bites, direct contact scans, x-ray imaging, tomography, ultrasound imaging, and other techniques for obtaining information about the position and structure of the teeth, jaw, gums, and other orthodontic-related tissues). From the resulting data, a digital data set can be obtained that represents an initial (e.g., pre-treatment) arrangement of the patient's teeth and other tissue. Optionally, the initial digital data set is processed to segment the tissue constituents from each other. For example, a data structure may be generated that digitally represents the crowns of individual teeth. Advantageously, a digital model of the entire tooth may be generated, including measured or inferred hidden surfaces and root structures, as well as surrounding bone and soft tissue.

The target arrangement of teeth (e.g., the desired and predetermined end result of orthodontic treatment) can be received from a clinician in a prescribed form, and can be calculated from basic orthodontic principles, and/or can be inferred from a clinical prescription using computer calculations. With a description of the desired final positions of the teeth and the digital representation of the teeth themselves, the final position and surface geometry of each tooth can be specified to form a complete model of the tooth arrangement at the end of the desired treatment.

Each tooth has both an initial position and a target position, and a movement path can be defined for the movement of each tooth. In some embodiments, these movement paths are configured to move the teeth in the fastest manner through the least amount of roundtrip (round-tripping) to bring the teeth from their initial positions to their desired target positions. Alternatively, the tooth path can be segmented, and the segments can be calculated to keep the motion of each tooth within a segment within threshold limits of linear and rotational translation. In this way, the end points of each path segment may constitute a clinically viable repositioning, and the collection of end points of the segments may constitute a clinically viable sequence of tooth positions, such that movement from one point to the next in the sequence does not cause collision of teeth.

In step 220, a force system for generating movement of one or more teeth along a movement path is determined. The force system may comprise one or more forces and/or one or more torques. Different force systems may cause different types of tooth movement, such as tilting, translation, rotation, squeezing, intrusion, tooth root movement, and the like. Biomechanical principles, modeling techniques, force calculation/measurement techniques, and the like (including those commonly used in the orthodontic art) can be used to determine an appropriate force system to apply to a tooth to effect tooth movement. Resources that may be considered in determining the force system to be applied include literature, force systems determined through experimental or virtual modeling, computer-based modeling, clinical experience, minimizing unwanted forces, and the like.

In step 230, an appliance geometry for an orthodontic appliance (the orthodontic appliance is configured to generate the force system described above) is determined. The geometry may include one or more tooth engaging structures that may be configured to engage a surface of at least one tooth. The tooth surface selected for engagement may be the interproximal, buccal or lingual, occlusal or any other surface of the tooth, depending on the nature of the forces to be generated on the tooth. The geometry may also include provisions for materials depending on location within the orthodontic appliance, such as provisions for certain portions to include elastic polymeric materials and other portions to include stiff polymeric materials.

The determination of the geometry, material composition, and/or properties of the appliance may be performed using a treatment or force application simulation environment. The simulation environment may include, for example, a computer modeling system, a biomechanical system or device, or the like. Alternatively, a digital model, such as a finite element model, of the appliance and/or teeth may be made. Finite element models can be created using computer program applications commercially available from a number of different suppliers. To create the solid geometric model, a Computer Aided Engineering (CAE) or Computer Aided Design (CAD) program may be used, such as that sold by Autodesk corporation of san Rafiel, CalifAnd (3) software. To create and analyze the finite element models, program products from a number of vendors may be used, including the finite element analysis software package from ANSYS, ltd, canangsburg, pennsylvania and the simulia (abaqus) software product from daso systems, waltham, massachusetts.

Optionally, one or more appliance geometries may be selected for testing or force modeling. As mentioned above, the desired tooth movement can be identified as well as the force system needed or desired to cause the desired tooth movement. Using a simulated environment, alternative appliance geometries can be analyzed or modeled to determine the actual force system resulting from using alternative appliances. Optionally, one or more modifications may be made to the alternative appliance, and the force modeling may be further analyzed in the manner described, for example, to iteratively determine an appliance design that produces a desired force system.

In step 240, instructions for manufacturing an orthodontic appliance having an appliance geometry are generated. The instructions may be configured to control a manufacturing system or apparatus to produce an orthodontic appliance having a specified appliance geometry. In some embodiments, the instructions are configured to manufacture the orthodontic appliance using direct manufacturing means (e.g., stereolithography, selective laser sintering, fused deposition modeling, direct injection, continuous direct manufacturing, multi-material direct manufacturing, etc.) according to the various methods described herein. In alternative embodiments, the instructions may be configured to indirectly manufacture the appliance, for example, by thermoforming.

Although the above steps illustrate a method 200 of designing an orthodontic appliance according to some embodiments, one of ordinary skill in the art will recognize a number of variations based on the teachings described herein. Some of these steps may include multiple sub-steps. Some of the steps may be repeated as many times as desired. One or more steps of method 200 may be performed by any suitable manufacturing system or apparatus, such as those embodiments described herein. Some of the steps may be optional, and the order of the steps may be changed as desired.

Fig. 3 illustrates a method 300 for digitally formulating an orthodontic treatment plan and/or design or manufacture of an appliance, according to an embodiment. The method 300 can be applied to any of the therapeutic procedures described herein and can be performed by any suitable data processing system.

In step 310, a digital representation of a patient's teeth is received. The digital representation may include surface topography data of the patient's oral cavity, including teeth, gum tissue, etc. The surface topography data may be generated by directly scanning the oral cavity, a physical model of the oral cavity (convex or concave), or an impression of the oral cavity, etc., using a suitable scanning device (e.g., a handheld scanner, a desktop scanner, etc.).

In step 320, one or more treatment stages are generated based on the digital representation of the teeth. These treatment stages may be incremental repositioning stages of an orthodontic treatment procedure designed to move one or more teeth of a patient from an initial tooth arrangement to a target arrangement. For example, the treatment stages can be generated by determining an initial tooth arrangement indicated by the digital representation, determining a target tooth arrangement, and determining a path of movement of one or more teeth in the initial arrangement required to achieve the target tooth arrangement. The path of movement can be optimized based on minimizing the total distance moved, preventing collisions between teeth, avoiding tooth movement that is difficult to achieve, or any other suitable condition.

In step 330, at least one orthodontic appliance is manufactured based on the generated treatment stage. For example, a set of appliances may be manufactured, each shaped according to the tooth arrangement specified for a particular treatment stage, such that the appliances can be sequentially worn by a patient to incrementally reposition teeth from an initial arrangement to a target arrangement. The appliance set may include one or more of the orthodontic appliances described herein. Manufacture of the appliance may include creating a digital model of the appliance that is to be used for input to a computer controlled manufacturing system. The orthosis can be formed using a direct manufacturing method, an indirect manufacturing method, or a combination of both, as desired.

In some cases, the design and/or manufacture of the appliance may not require various different arrangements or stages of treatment. As shown in phantom in fig. 3, the design and/or manufacture of the orthodontic appliance, and possibly the particular orthodontic treatment, may include using a representation of the patient's teeth (e.g., receiving a digital representation 310 of the patient's teeth), and then designing and/or manufacturing the orthodontic appliance based on the representation of the patient's teeth in the arrangement represented by the received representation.

FIG. 4 is a simplified block diagram of a data processing system 400 that may be used to perform the methods and processes described herein. Data processing system 400 typically includes at least one processor 402 that communicates with one or more peripheral devices via a bus subsystem 404. These peripheral devices typically include a storage subsystem 406 (memory subsystem 408 and file storage subsystem 414), a set of user interface input and output devices 418, and an interface to an external network 416. This interface is shown schematically as a "network interface" block 416 and is coupled to corresponding interface devices in other data processing systems via a communications network interface 424. Data processing system 400 may include, for example, one or more computers, such as personal computers, workstations, mainframes (mainframes), laptops, etc.

The user interface input devices 418 are not limited to any particular device and may generally include, for example, a keyboard, pointing device, mouse, scanner, interactive display, touch pad, joystick, and the like. Likewise, a variety of user interface output devices can be used in the system of the present invention, and can include, for example, one or more of a printer, a display (e.g., visual, non-visual) system/subsystem, a controller, a projection device, an audio output, and the like.

Storage subsystem 406 holds the basic required programming, including computer-readable media with instructions (e.g., operational instructions, etc.) and data structures. The programming modules discussed herein are typically stored in storage subsystem 406. Storage subsystem 406 generally includes a memory subsystem 408 and a file storage subsystem 414. Memory subsystem 408 typically includes a plurality of memories (e.g., RAM 410, ROM412, etc.) including a computer readable memory for storing fixed instructions, and data during program execution, a basic input/output system, etc. File storage subsystem 414 provides persistent (non-volatile) storage for program and data files, and may include one or more removable or fixed drives or media, hard disks, floppy disks, CD-ROMs, DVDs, optical disk drives, and the like. One or more of the storage systems, drives, etc. may be located at a remote location, e.g., connected through a server on a network or through the internet/world wide web. In this context, the term "bus subsystem" is used generally to include any mechanism for bringing various components and subsystems into desired communication with one another, and may include a wide variety of suitable components/systems that may be known or otherwise deemed suitable for use in the system. It will be appreciated that the various components of the system may, but need not, be in the same physical location, but may be connected via a variety of local or wide area network media, transmission systems, and the like.

The scanner 420 includes: any means for obtaining a digital representation (e.g., an image, surface topography data, etc.) of a patient's teeth (e.g., by scanning a physical model of the teeth such as the cast 421, by scanning an impression obtained through the teeth, or by directly scanning an oral cavity), the digital representation being available from the patient or a treating professional (e.g., an orthodontist); and means for providing the digital representation to data processing system 400 for further processing. The scanner 420 may be located at a remote location relative to the other components of the system and may communicate image data and/or information to the data processing system 400, for example, via the network interface 424. The manufacturing system 422 manufactures the appliances 423 based on the treatment plan (including the data set information received from the data processing system 400). The maker 422 may, for example, be located at a remote location and receive data set information from the data processing system 400 via the network interface 424.

The data processing schemes of the methods described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in suitable combinations of the above. The data processing apparatus can be implemented in a computer program product tangibly embodied in a machine-readable storage device for execution by a programmable processor. The data processing steps can be performed by a programmable processor executing program instructions to perform functions by operating on input data and generating output. The data processing schemes can be implemented by one or more computer programs that can run on a programmable system including one or more programmable processors operatively coupled to a data storage system. Generally, a processor will receive instructions and data from a read-only memory and/or a random access memory. Storage devices suitable for tangibly embodying computer program instructions and data include all forms of non-volatile memory, such as: semiconductor memory devices such as EPROM, EEPROM, and flash memory devices; magnetic disks such as internal hard disks and removable disks; magneto-optical disks; and a CD-ROM disk.

The ability to directly manufacture the appliance shell enables a wide variety of structures to be produced to allow the orthodontic forces applied to the teeth to be adjusted in a variety of ways. Fig. 5A-5E illustrate a number of different ways in which the appliance shell may be manufactured to engage the tooth surface.

Fig. 5A shows the fabricated coupling mechanism 500 between the shell 501 and the teeth 503. The manufactured shell 501 has interproximal tooth engaging structures 502, the interproximal tooth engaging structures 502 being manufactured to fit in the interproximal areas between the teeth 503. As the interproximal tooth engagement structure 502 and tooth 503 come into contact, forces may be transferred from the shell 501 to the tooth 503. This force may provide an orthodontic force on one of the teeth 503 or on both teeth 503, thereby causing the teeth to move in a desired direction.

Fig. 5B shows another coupling mechanism 510 between the shell 511 and the teeth 512 being manufactured. The shell 511 is manufactured with a tooth engaging structure 513, the tooth engaging structure 513 being configured to engage a bite edge 514 located on the gingival portion of the tooth 512. For example, engagement structure 513 may be manufactured with a greater thickness than other portions of housing 511, or from a different material than housing 511, to further customize the force that can be applied through contact undercut 514. Of the forces that may be exerted on the teeth 512 by contact forces, the force between the engagement structure 513 and the bite edge 514 is an extrusion force that may be exerted by applying a force on the shell 511 in the occlusal direction, which may be balanced by a force in the gingival direction due to contact between the shell 511 and one or more other teeth.

Fig. 5C shows how the shell can be made to engage the bite edge of the teeth. Molar teeth 515 are in contact with housing 516, which includes undercut engagement surfaces 517, which exert an extrusion force 518 on undercut 519. The extrusion force 518 may be adjusted (tailor, cut) to cause the molar teeth 515 to be extruded.

Fig. 5D and 5E illustrate other options available in the design of the manufactured housing. In fig. 5D, the housing 520 may be manufactured with a smooth outer layer 521 and an irregular inner layer 522. The shape of the inner layer may be altered in any desired manner to customize the engagement between the shell 520 and the teeth. For example, different portions of the surface 522 may be made thicker to apply a set of forces to the surface of the tooth in a particular direction at a particular point, while other portions of the surface 522 may be made thinner to allow the tooth to move in a certain direction or to avoid applying forces in undesired directions. Another alternative configuration is shown in the shell 530 of fig. 5E, which is manufactured with a portion 523 that closely conforms to the tooth surface and a second portion 524 extending outwardly from the tooth surface, for example, to enable the attachment to fit within the surface portion 524 and optionally engage with the surface portion 524.

Fig. 6 illustrates a plurality of forces that may be applied to cause rotation of a tooth about a vertical axis. Fig. 6 shows the shell-engaging teeth from two different perspectives. Side view 600 shows a view in the mesial-distal direction, where the shell 601 as manufactured contacts the teeth 602 to induce rotation about a vertical axis 605. The shell 601 is manufactured to have tooth engaging surfaces 603 and 604 on opposite sides of the tooth. The engaging surface 603 exerts a force 606 on the lingual surface of the tooth 602, while the surface 604 exerts a force on the distal side. By designing the housing 601 and the engagement surfaces 603 and 604, the force on the teeth 602 can be adjusted to cause rotation.

The top view 610 shows the system along the occlusal-gingival axis (corresponding to the vertical axis 605). Contact between the engaging surface 603 and the lingual side of the tooth 602 produces a force 613 in the buccal direction. Contact between the engaging surface 604 and the buccal side of the tooth 602 produces a force 614 in the lingual direction. These opposing forces generate a moment 615 about the vertical axis of the tooth 602, which can rotate the tooth. The forces 613 and 614 may be adjusted by the design of the housing 601 and the engagement surfaces 603 and 604. For example, housing 601 may be made of a flexible material, while engaging surfaces 603 and 604 may comprise a rigid material. If the shell structure is designed so that the equilibrium positions of the engaging surfaces 603 and 604 are closer together (compared to the width of the teeth), the engaging surfaces 603 and 604 will be biased apart by the teeth 602 when the appliance is worn. This bias stores elastic potential energy in the flexible housing, causing forces 613 and 614 to be generated as the housing itself is pulled back toward its equilibrium configuration. The magnitude of this force can be varied by varying such characteristics as the degree of displacement of the engagement surfaces 603 and 604, the elasticity of the flexible portion of the housing 601, and the like.

Fig. 7A illustrates forces that may be beneficially applied to teeth using manufactured engagement structures (e.g., interproximal engagement structures). The tooth 700 contacts interproximal tooth engagement structures 701 and 702 to cause rotation 703. The interproximal tooth engaging structures 701 and 702 are connected to a shell that is manufactured to pull the interproximal tooth engaging structures toward each other along the proximal-to-distal central axis. Contact forces between the interproximal tooth engagement structures 701 and 702 and the tooth 700 cause rotation 703 of the tooth.

Another type of movement that may be caused by a suitably manufactured engagement structure and shell is shown in the movement of the tooth 710. Tooth 710 engages interproximal engagement structures 711 and 712 near the gingival surface and engages engagement structure 713 near the occlusal surface to induce a tilting motion in tooth 710. The housing is configured to pull adjacent engagement structures 711 and 712 in a distal direction while pulling engagement structure 713 in a mesial direction. The opposing forces from the contact between the engagement surface and the tooth 710 generate a net moment (net moment) about the buccal-lingual axis of the tooth 710, resulting in a tilt of the tooth in the mesial direction as the tooth rotates about the buccal-lingual axis. The interproximal engagement structures 711 and 712 are fabricated on the opposite lingual and buccal sides to provide a balanced force so as not to cause unnecessary rotation about the vertical axis of the tooth 710. In some cases, such as when there is a substantial interproximal gap, the engagement structures 711 and 712 may be merged into a single engagement structure.

Fig. 7B illustrates a number of exemplary positions in which an interproximal engagement structure may be designed to engage teeth. Tooth 730 is shown with the following 4 interproximal engagement regions: a proximal lingual area 740, a distal lingual area 745, a proximal buccal area 750, and a distal buccal area 755. Typically, the interproximal engagement structures that contact the teeth will be manufactured so that they contact the surface of the teeth in at least one of these areas. Typical contact points may be located on the buccal-lingual axis at approximately the same distance from the center of the tooth as the farthest point from the tooth, or closer to the center relative to the farthest point. In some cases, the interproximal tooth engaging structures may be manufactured so that they are entirely between the teeth, allowing them to contact the teeth generally centrally. For example, the interproximal engagement structures may contact tooth 730 between regions 740 and 750, or contact tooth 730 between regions 745 and 755. The height of the interproximal engagement structures may also be freely varied so that they may contact the teeth at any of a number of heights.

Another configuration of a directly fabricated shell that enables translational movement of one or more teeth is shown in fig. 8A. The gap 801 between the front tooth 802 and the rear tooth 803 may be closed (e.g., by applying the force shown in fig. 2). The closing of the gap will cause the teeth 802 and 803 to move toward each other. The housing 805 may be manufactured in a manner that permits, urges, or guides such movement. For example, the shell 805 may include a proximal portion (medial portion)805 that contacts the teeth at a proximal end of the gap 801, a distal portion (distal portion)806 that contacts the teeth at a distal end of the gap 801, and a gap portion 807 that is at least partially within the region of the gap 801. To allow the teeth 802 and 803 to move to fill the gap 801, the gap 807 can be made more flexible than the rest of the shell 804. For example, gap 807 may be made thinner than portions 805 and 806. Alternatively or additionally, gap 807 may be fabricated to have a more flexible material than portions 805 and 806. In some embodiments, gap 807 may be configured to apply a resilient force to close gap 801. For example, gap 807 may comprise a directly fabricated spring structure.

Fig. 8B illustrates how the interproximal engagement structures may be employed to assist in anchoring the shell being manufactured to one or more teeth, for example, to provide the motion shown in fig. 2 and 8B. It is desirable to stably anchor housing 810 to rear teeth 813 while closing gaps 811 between front teeth 812 and rear teeth 813. Typically, such anchoring may be achieved by contacting the open posterior tooth surface (e.g., surface 814). However, additionally or alternatively, the appliance shell may be manufactured with an interproximal engagement structure such as structures 815 and 816. These structures may engage the abutment surfaces of the teeth 813 to provide an anchoring force against which tooth movement forces are applied. In some cases, structures 815 and 816 include a single connecting structure that extends across the interproximal gap. Such a structure can be used to surround a large portion of the surface area of the teeth. For example, in various aspects, the interproximal structures disclosed herein may provide a tooth-receiving structure that contacts or covers most or all of the peripheral surfaces of the teeth, including the interproximal, lingual, and buccal surfaces of the teeth. For example, such tooth receiving structures may cover 50% or more of the peripheral surface of a tooth (such as a molar tooth). In some cases, the tooth receiving structure can cover 60% or more, 70% or more, or 80% or more of the circumference of the tooth. In particular, tooth-receiving structures for incisors, canines, and premolars can provide such a large coverage area. Alternatively, less tooth coverage may be used; for example, less than 50%, less than 20%, less than 10%, or less than 5% of the circumferential surface of the tooth surface may be covered. In some cases, the first tooth-receiving cavity can be shaped to engage a majority of a peripheral surface of the first tooth when worn, and the second tooth-receiving cavity can be shaped to engage a smaller portion of a peripheral surface of the second tooth when worn. Moreover, the interproximal structures disclosed herein can provide engagement (in combination with walls on the lingual and buccal surfaces) along most or all of the circumference of the tooth, e.g., about 90% or more of the circumference of the tooth, or even about the entire circumference of the tooth. Such a structure not only allows for secure anchoring of the tooth, but also allows for application of force in many different directions and allows for constraint or movement of the tooth to a particular position and orientation. For example, when moving teeth through an interproximal engagement structure, the structure may also prevent unwanted rotation of lateral movement by holding the teeth in a desired orientation and preventing the teeth from moving out of a predetermined trajectory. This feature may further be beneficial for the treatment regime since errors due to unwanted movement or rotation may be reduced, thereby enabling a more accurate estimate of the treatment effect.

Further illustrating the range of tooth movement that can result from the direct fabrication of interproximal structures on orthodontic appliances, fig. 9A illustrates how a plurality of tooth engaging structure configurations can be configured to treat interproximal spaces. Interproximal tooth engaging structures 901 are positioned on opposite sides of two central incisors 902 to provide tooth-moving forces on each central incisor toward the midline. A plurality of additional tooth engaging structures 903 are positioned closer to the occlusal surface along the midline to provide counter moment. Each tooth engaging structure is attached to the resilient portion of the appliance such that the structure is offset from its equilibrium position by the geometry of the tooth with which it is in contact. This causes each tooth engaging structure to exert a resilient force in the respective direction indicated in fig. 9A. The integrated effect of these forces is a translation of the central incisor 902 towards the midline, closing the interproximal space 904. It will be appreciated by those skilled in the art that this design can be used to close gaps between other pairs of teeth as well.

Fig. 9B illustrates how interproximal tooth engagement structures may be employed to induce midline shift. The interproximal tooth engagement structures 911 may be manufactured such that each interproximal tooth engagement structure contacts a selected side of a tooth, such as the right side of each of the central incisors 912 as illustrated. Opposite each interproximal tooth engaging structure 911 is another tooth engaging structure 913 positioned near the occlusal surface to provide counter torque. Each tooth engaging structure is attached to the resilient portion of the appliance such that the structure is offset from its equilibrium position by the geometry of the tooth with which it is in contact. This causes each tooth engaging structure to exert a resilient force in the respective direction indicated in fig. 9B. The integrated effect of these forces is a translation of the central incisor 912 to the left, producing a midline shift 914 towards the left. By shifting the position of each structure relative to the midline in a mirror image, motion to the right may instead be induced. It will be appreciated by those of ordinary skill in the art that other teeth, including individual teeth or groups of more than two teeth, may also be moved using this design, as desired.

Fig. 9C illustrates how a pair of interproximal tooth engaging structures disposed oppositely on the buccal and lingual sides of the teeth may be used to apply tooth movement forces in any of the various configurations described herein. Fig. 9C illustrates a view from the occlusal surface of a plurality of tooth engaging structures configured to close the interproximal space (as shown in fig. 9A). Each interproximal tooth engaging structure 901 of fig. 9A is replaced with a pair of interproximal tooth engaging structures on opposite buccal and lingual sides of the incisors 902. These structures (also known as buccal interproximal tooth engagement structures 901B and lingual interproximal tooth engagement structures 901L) integrally provide tooth movement forces in the directions shown, while either buccal or lingual forces may be counteracted by the forces of the corresponding structures on the opposite face of the tooth. Likewise, the counter-moment tooth engaging structure 902 (located near the occlusal surface) is replaced with a buccal tooth engaging structure 903B and a lingual tooth engaging structure 903L to achieve a similar effect. This configuration of the tooth engaging structure may be desirable, for example, when the teeth are arranged very closely to enable the tooth engaging structure to fit within the space between the teeth.

Figure 9D illustrates how the appliance may be configured such that the tooth engaging structure exerts a force on the teeth. As shown, the appliance is worn on the patient's teeth such that the appliance and the tooth engaging structure each contact one or more of the patient's teeth. The tooth engaging structure includes a solid tab (as labeled) that is attached to the appliance. In the attached region, the orthotic comprises an elastic material such that the solid projection is movable. The appliance is manufactured such that the position of the physical protrusion in the nominal design of the appliance is different from the position it would have when worn in the patient's mouth. Typically, this difference may be in the range of about 1 to 2mm or so, and the direction in which the tabs deflect when worn is opposite to the direction of the desired force. When installed in the patient's mouth, the geometry of the teeth will guide the projections into the interproximal spaces to stretch the elastic portion of the appliance and store elastic potential energy therein. This elastic potential energy causes a restoring force that can be used to produce tooth movement.

The use of a hybrid resilient and rigid material for the removable appliance shown in FIG. 9D provides a number of advantages over prior systems that use only rigid materials. First, the elastomeric material allows force to be applied to the tooth at multiple points of contact. With rigid materials alone, it is not possible in some embodiments to apply force to more than three points of the tooth simultaneously, as unstable systems may occur with four or more points of contact. Without being bound by any particular theory, this may also be caused by reasons similar to "a four-legged seat will rock while a three-legged seat will not". In rigid materials, little error is allowed, whether force is applied or not. Small movements of the teeth or imperfections in the appliance may result in the forces being removed. In some cases, this restriction can result in the creation of unwanted forces and moments, while in other cases the desired forces and moments cannot be applied. The use of an elastic material solves this potential problem because the force applied to each contact point can now be smoothly varied. The use of rigid materials in combination with the contact points enables variable forces to be applied at different precisely selected points on each tooth.

Second, the use of a blend of elastomeric and rigid materials provides a greater operating range than is available in prior systems. The removable appliances of some existing systems have an operable range of about 0.2 to 0.25mm, and several tens of appliances may be required to move teeth over a predetermined trajectory of several millimeters. The elastic material can provide a greater range of motion: for example approximately 1 to 2mm or more. This enables each appliance to move the teeth a considerable distance, allowing a quarter or tenth, if not less, of the number of appliances previously required using some systems to adjust the patient's teeth.

Third, the large range of motion allows for more flexibility (flexibility) in treatment. In some cases, the patient's teeth do not move in an expected setting in response to the applied force. In these cases, an appliance manufactured based on the expected tooth positions may not match the actual positions of the patient's teeth. An orthosis made from a blend of elastic and rigid materials allows a greater range of movement and therefore greater flexibility. An appliance comprising an elastomeric material is capable of receiving teeth despite the patient's teeth being offset by 1 or 2mm or more from their intended position. This greater flexibility can avoid situations where the appliance may also need to be remanufactured to account for undesired tooth movement.

An appliance having an interproximal engagement structure disclosed herein may be provided as a series of appliances having different interproximal engagement structures and/or tooth receiving cavities in order to provide tooth movement forces to move teeth along a trajectory from a first position and orientation to a second position and orientation. In some cases, the series of appliances may include multiple interproximal engagement structures of different forms to better engage the interproximal spaces at each treatment step. For example, fig. 10A shows a portion of a plurality of appliances 1010, 1020, and 1030 configured to act sequentially on teeth 1001 and 1002 to engage interproximal spaces of the teeth, thereby generating tooth movement forces. Each tooth illustrated herein may also correspond to a tooth-receiving cavity shaped to receive the respective tooth; thus, for example, appliance 1010 includes tooth receiving cavities shaped to receive teeth 1001 and 1002. In some cases, the interproximal engagement structures disclosed herein may be formed contiguously with, or replaced by, certain portions of the tooth-receiving cavity. The appliance 1010 includes a plurality of interproximal engagement structures 1014, one on each buccal side and lingual side. The interproximal engagement structures 1014 extend into the interproximal space between the teeth 1001 and 1002 and do not pass completely through the interproximal spaces. This configuration may be used when the teeth 1001 and 1002 have little or no interproximal space (e.g., when the teeth are in close contact together). The interproximal engagement structures 1014 may apply a tooth-moving force, for example, when the appliance walls 1012 are pressed inward against the teeth, or when a force transmitted through the appliance from other portions of the appliance (e.g., anchors as shown in fig. 8B) pulls or urges the teeth. The interproximal engagement structures 1014 may also apply various forces to hold the teeth 1001 and 1002 in place (e.g., by resisting other tooth movement forces applied to the teeth). The interproximal engagement structures 1014 may also provide lingual or buccal corrective forces, e.g., by applying a resistive force to the teeth 1001 and 1002 to urge the teeth in the buccal or lingual direction by providing more room in the corrected (aligned) position or orientation than in the uncorrected (misaligned) position or orientation.

The appliance 1020 may be worn when the teeth 1001 and 1002 have a small interproximal gap, but the interproximal gap is sufficient to allow the interproximal engagement structures to fit between the teeth. Thus, the appliance 1020 includes an interproximal engagement formation 1024 which passes through the interproximal spaces between the teeth 1001 and 1002 and abuts the lingual and buccal appliance walls 1022. For example, appliance 1020 can be used after appliance 1010 has slightly widened the interproximal gap between teeth 1001 and 1002. The interproximal engagement structures 1024 may comprise a solid structure that is wider near the lingual and buccal surfaces of the appliance, and narrows in the interproximal region as shown to conform to the shape of the teeth. Alternatively, the interproximal engagement structures 1024 may include thin walls that are adjacent to (and optionally connected to) each other in the interproximal regions, thereby providing space between these walls. As another alternative, the interproximal engagement structures 1024 may comprise a single layer of walls having a generally uniform thickness extending directly from the lingual side to the buccal side of the appliance. The interproximal engagement structures 1024 may extend from the bite area down to a point near the gums, or not as far as such point, as desired. The structure may be shaped such that its vertical dimension matches the shape of the tooth above or below the point of contact of the teeth 1001 and 1002, or alternatively both above and below. Thus, particularly where other interproximal structures are provided on opposite sides of the tooth, the teeth 1001 and 1002 may be substantially surrounded by walls that contact the tooth surface.

A further step in the treatment of appliance 1030 is set forth (now) in which appliance 1030 can be worn with teeth 1001 and 1002 having a large interproximal space. Accordingly, the interproximal engagement structure 1034 is wide and may comprise a solid piece extending across the gap or two separate walls, each extending between the lingual and buccal sidewalls 1032, and each contacting a single tooth with a space therebetween. Alternatively, the interproximal engagement structures may comprise a resilient or elastic material. For example, the engaging structure may comprise a stiff material at and around the point of contact with the teeth, while comprising an elastic material extending to the buccal and/or lingual sidewalls. Alternatively, the interproximal engagement structures may comprise only elastomeric materials, or only rigid materials. While the appliances 1010, 1020, and 1030 have been described as widening the interproximal spaces between the teeth 1001 and 1002 in sequence, it should be understood that the reverse procedure is also possible. For example, the interproximal engagement structures 1034, 1024, and 1014 can be used to provide resistance or corrective forces to the teeth 1001 and 1002 as the teeth 1001 and 1002 move together, in which case the appliances 1030, 1020, and 1010 can be worn in sequence as the interproximal spaces narrow to guide the teeth 1001 and 1002 to the final corrective position. Also, the position and angle of the interproximal engagement structures may be varied among the plurality of appliances to adjust the amount of force applied, the angle of force applied, and the position at which the force is applied to the teeth in order to produce the desired tooth movement. For example, as the teeth 1001 and 1002 move, the tooth position or position can also be changed by using subsequent appliances, correcting by adjusting the force applied to the teeth. The interproximal engagement structures may also be shaped to engage multiple surfaces of the tooth or a continuous surface across the interproximal spaces, and be shaped to apply a restraining force to guide the tooth along a trajectory, both in position and orientation.

In addition to varying the width to cause tooth movement, appliances having interproximal structures may also vary the contact angle of the interproximal structures with the teeth, which may be used to cause more complex motions such as rotation. For example, fig. 10B illustrates a plurality of appliances 1040, 1050, and 1060, each including a respective interproximal engagement structure 1044, 1054, and 1064 extending in the lingual-buccal direction between appliance walls 1042, 1052, and 1062. These interproximal engagement structures are shaped to pass through the interproximal spaces between the teeth 1003 and 1004. Each interproximal engagement structure is oriented at a different angle and engages teeth 1003 and 1004 at different locations to apply tooth movement forces. Initially, teeth 1003 and 1004 are tilted out of alignment; a tooth movement force that rotates the tooth toward the desired orientation is applied through contact with the interproximal engagement structures 1044. The force applied need not be perpendicular to the contact surface of the teeth; for example, the interproximal engagement structures may be oriented at an angle such that the force comprises friction between the surface of the appliance and the teeth. This frictional force can be compensated for when determining the force that needs to be transferred to the teeth. After some degree of movement, the appliance 1050 is provided with an interproximal engagement structure 1054, which interproximal engagement structure 1054 is configured to contact the teeth at different angles to continue to impart the desired movement. Finally, the appliance 1060 provides the interproximal engagement structures 1064 at a third angle, with the teeth 1003 and 1004 reaching their desired orientation.

Fig. 11 shows another example of tooth movement using an interproximal structure. Teeth 1001 and 1002 are not initially aligned in the lingual-buccal direction and require correction in order to be properly aligned. In particular, tooth 1001 is shown as not initially aligned in the lingual direction (up), while tooth 1002 is not aligned in the buccal direction (down). Accordingly, a plurality of appliances 1110, 1120, and 1130 and corresponding interproximal engagement structures 1114, 1124, and 1134 are provided to apply tooth movement forces. These appliances are manufactured to have interproximal engagement structures with a resting length (stopping length) less than the distance across the gap from the lingual surface of tooth 1001 to the buccal surface of tooth 1002. The structure of the appliance 1110 thus stretches in the buccal-lingual direction when worn, thus providing a force that tends to move the teeth 1001 and 1002 into alignment as shown. The stretching of the orthosis 1110 can include stretching of the elastic material in the interproximal formations 1114, flexing of the elastic formations in the orthosis walls 1112, or a combination thereof, wherein both the walls 1112 and the interproximal formations 1114 include a resilient or elastic material. As the teeth move toward alignment, a new appliance 1120 can be provided with a correspondingly shorter length of the interproximal structures 1124 to maintain tooth movement force. Appliance 1130 illustrates a further step of utilizing an appliance wherein interproximal structures 1134 comprise a length equal to the desired lingual-buccal distance (e.g., the width of teeth 1001 and 1002), thereby causing teeth 1001 and 1002 to achieve the desired orthodontic correction.

In another aspect, the appliance can be manufactured to include a plurality of interproximal structures that are configured to fit within and apply individual forces to the interproximal regions of the teeth. Fig. 12A and 12B illustrate a portion of respective appliances 1210 and 1220, each including an interproximal engagement structure to apply force to teeth 1201 and 1202. In the appliance 1210 of fig. 12A, resilient or elastic appliance walls 1212 are provided on opposite lingual and buccal sides of the teeth 1201 and 1202. An interproximal engagement structure 1214, comprising a relatively stiff material, is disposed on the appliance wall and is positioned to fit in the interproximal region between the teeth 1201 and 1202. Although shown as a triangular wedge, it should be understood that the interproximal engagement structures 1214 may take on a variety of shapes, such as being shaped to follow the contours of the interproximal areas of the teeth 1201 and 1202. The size of the interproximal engagement structures 1214 is sufficiently large to be larger than the standard spacing between the appliance walls 1212 and the interproximal spaces; thus, because the wall comprises an elastic material, the wall deforms when worn, as shown by deformation 1216. The elasticity of the deformed material provides a restoring force that drives the interproximal engagement structures into the interproximal spaces, thereby providing tooth movement forces on the teeth 1201 and 1202, as shown.

Fig. 12B illustrates a second configuration of the appliance 1220 having stiff walls 1222 and resilient interproximal engaging structures 1224, the interproximal engaging structures 1224 being configured to engage the teeth 1001 and 1002 in the interproximal spaces. Likewise, the interproximal engagement structures 1224 are too large to fit in the interproximal gaps. In this case, the interproximal engagement structures 1224 comprise an elastomeric material; accordingly, the interproximal engagement structures deform to fit in the gap, as represented by the curvature of the structure 1224 along the surfaces of the teeth 1201 and 1202, thereby providing a deformation restoring force to provide tooth movement forces to the teeth 1201 and 1202. As shown in fig. 12A, while interproximal engagement structures 1224 are shown as deformed triangular wedges, it should be understood that interproximal engagement structures 1224 may take on a variety of shapes, such as shaped to follow the contours of the interproximal areas of teeth 1201 and 1202 before and after deformation. It should also be understood that with reference to fig. 12A and 12B, the interproximal engagement structures 1214 and 1224 may be positioned on either side of the tooth, such as the lingual, buccal or occlusal sides, while additional interproximal engagement structures may be positioned to simultaneously engage combinations of the sides of the interproximal area, such as on both the lingual and buccal sides of the interproximal area. Furthermore, similar appliances may be provided in which both the walls of the appliance and the abutment engaging structure are resilient and therefore both deformable to apply a force.

The interproximal engagement structures may also be used to exert forces on multiple individual tooth surfaces. Fig. 13A illustrates an appliance 1310 in which a first interproximal engagement structure 1314 passes through the interproximal region between the two teeth 1301 and 1302, and a second interproximal engagement structure 1315 passes through the interproximal region between the two teeth 1303 and 1304. Two interproximal engagement structures 1314 and 1315 are coupled to the walls of the appliance 1310 and are positioned such that the distance between the two structures is less than the initial distance between the respective interproximal gaps. Thus, the abutment engagement structure and/or appliance walls are distorted out of their equilibrium positions, thereby creating a restoring force that urges the teeth 1302 and 1303 to move as shown, thereby moving the two teeth into alignment by closing the gap 1305. Multiple appliances may be used to apply tooth movement forces in this manner in succession; for example, the appliance 1320 includes adjacent engagement structures 1324 and 1325 that are displaced to different positions (to account for the interfering movement of the patient's teeth). The interproximal engagement structures of the appliances 1320 may thus continue to urge the patient's teeth along a desired trajectory. It should be understood that by moving the teeth 1302 and 1303 closer together, the teeth 1302 and 1303 are moved farther away from the teeth 1301 and 1304, respectively. This may remove forces from the teeth 1302 and 1303 that are applied to the teeth 1301 and 1304, which may cause the teeth 1301 and 1304 to move further into better alignment; for example, the teeth may follow their neighboring teeth toward the gap 1305 to improve the overall balance of the tooth spacing.

The tooth-moving force described with reference to figure 13A may be applied not only by a plurality of interproximal engagement structures, but also by each individual interproximal engagement structure. For example, fig. 13B shows an appliance 1330 having a single interproximal engagement 1334 where the single interproximal engagement 1334 is disposed across the interproximal spaces between teeth 1351 and 1352. The interproximal engagement structures 1334 are configured to apply a force on the tooth 1352 to urge the tooth in a desired direction; for example, into space 1355. For example, the appliance may apply tooth movement forces based on the anchoring of one or more tooth receiving cavities located at a position on the appliance, as shown in fig. 8B. Optionally, the anchors may include corresponding interproximal engagement structures. By repositioning the interproximal engagement structures to account for the interference motion of the teeth, the series of appliances can continue to urge the teeth 1352 along a desired trajectory. As discussed above with reference to fig. 13A, movement of tooth 1352 can also eliminate forces between teeth 1352 and 1351, thereby displacing the two teeth into better alignment.

While interproximal engagement structures (such as structures 1334 and 1344) may in some cases apply forces across the surface of the tooth, in other cases, the interproximal engagement structures may engage the interproximal areas of the tooth in multiple locations to apply multiple forces, resulting in a net force and/or a net moment to cause tooth movement. For example, fig. 13C shows a plurality of teeth 1361, 1362, and 1363 in which the appliance includes one or more interproximal engagement structures that engage the tooth 1362 in order to urge the tooth 1362 mesially toward the tooth 1363. Contact of one or more interproximal engagement structures on the surface of the tooth 1362 generates a plurality of forces. The first force 1364 on the lingual side urges the tooth 1362 in the buccal direction and the mesial-distal direction simultaneously, while the second force 1365 urges the tooth 1362 in the lingual direction and the mesial-distal direction simultaneously. The buccal and lingual components of the plurality of forces are partially or completely eliminated while simultaneously adding a mesial-distal force to produce a resultant force 1366 urging tooth 1362 in a mesial-distal direction toward tooth 1363. Thus, the tooth movement forces and moments described herein can be generated, for example, as a resultant of two or more tooth movement forces or moments.

Direct fabrication techniques such as additive manufacturing described herein are particularly advantageous for fabricating interproximal structures because such structures can yield properties that were not available in the prior art (e.g., indirect manufacturing). For example, the interproximal spaces of teeth are narrow, and therefore interproximal structures shaped to fit in these spaces should be thin enough to fit with them. Interproximal engagement structures also often require sharply curved surfaces with small radii of curvature. For example, polymeric appliances made according to the prior art are limited to the achievable radius of curvature, with the radius of curvature of a portion of the appliance being constrained by the thickness of the material. Such restraint is particularly relevant to the force application portion of the appliance (as used with the interproximal engagement structures described herein). For example, in contrast to existing polymeric appliances, the appliances disclosed herein and made according to the methods disclosed herein can produce structures that include tooth engaging structures in which the radius of curvature is less than one-third of the thickness of the structure.

FIG. 14 illustrates an exemplary structure 1400 having a protrusion 1430, the protrusion 1430 having a radius of curvature 1440. The structure also includes a thickness 1420, and the radius of curvature 1440 is less than 30% of the thickness 1420. This allows the projection 1430 to extend into spaces such as interproximal spaces and apply force in a manner not possible in prior devices. In some embodiments, a projection (e.g., projection 1430) can extend from the shell to engage the tooth surface, for example, at an apex or side of the projection. Additionally or alternatively, the projections may extend from other structures; for example, a first tab may extend from a second tab or other structure to contact a tooth surface. In some cases, the projections may also extend from the tooth surface, such as projections on the outer surface of the appliance. If desired, other structures having a small radius of curvature of less than 20%, less than 10%, or even less than 5% of the material thickness can be manufactured, thereby allowing the appliance material to be extended to previously inaccessible dentists. While structure 1400 is shown as a convex structure, it is understood that similar concave structures may be fabricated with a radius of curvature that is less than 30%, less than 20%, less than 10%, or even less than 5% of their respective thicknesses, thereby enabling the tooth-receiving cavity to include even a tight enclosure for, for example, sharp dental structures.

The improved limits (in terms of thickness and radius of curvature) provided by direct manufacturing allow the manufacture of appliances having surfaces that closely match the patient's teeth, thereby improving the engagement of the surfaces. For example, the engagement surfaces (e.g., interproximal engagement surfaces, tooth-receiving cavities, or occlusal surfaces) may be manufactured with irregular shapes that match the surfaces of the teeth to be engaged. For example, irregular shapes of 100 microns or less may be matched by fabricating respective engagement surfaces having respective irregular shapes (e.g., protrusions and depressions) with a resolution of 100 microns or more. Such irregular shapes have a relatively small radius of curvature. Existing polymeric appliances have limitations in this regard because such small structures require proportionately thin materials (which have lower load bearing capabilities). In contrast, the methods and appliances disclosed herein allow for the manufacture of such structures and are not constrained by the thickness of the material in which such structures are provided.

Each of the structures disclosed herein, including those shown in fig. 1, 2, and 5-14, can be used in combination, independent, or in combination in an appliance such as a polymeric shell appliance. The interproximal engagement structures disclosed herein may be particularly made of polymeric materials and be part of such appliances. Such appliances may be manufactured using direct manufacturing techniques disclosed herein (e.g., additive manufacturing, etc.).

While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.