阅读说明：本技术 隐形矫治器的自适应加工方法 (Self-adaptive processing method of invisible appliance ) 是由 陈关宝 朱彤 于 2020-03-21 设计创作，主要内容包括：隐形矫治器的自适应加工方法,包括获取牙颌模型,在牙颌模型上真空热塑形成初始牙膜,获得初始牙膜的数字模型,并在数字模型上生成切割曲线；以切割曲线上的点作为刀具的第一落点,以偏置后切割曲线上对应的点作为第二落点,第一落点和第二落点约束刀具的形态倾角。本发明的优点在于自适应性好,可对于畸形牙膜自行进行调整切割角度,避免了切割碰撞的产生；能根据牙齿自身的特征自动找到关键点,然后根据关键点进行差值,自动计算路径需要的倾斜角度,从而避免自动切割中出现过切,漏切等情况的出现。(The self-adaptive processing method of the invisible appliance comprises the steps of obtaining a dental model, forming an initial dental film on the dental model through vacuum thermal molding, obtaining a digital model of the initial dental film, and generating a cutting curve on the digital model; and taking a point on the cutting curve as a first drop point of the cutter, taking a corresponding point on the offset cutting curve as a second drop point, and constraining the form inclination angle of the cutter by the first drop point and the second drop point. The invention has the advantages that the self-adaptability is good, the cutting angle can be automatically adjusted for the deformed dental film, and the generation of cutting collision is avoided; the key points can be automatically found according to the characteristics of the teeth, then the difference value is carried out according to the key points, and the inclination angle required by the path is automatically calculated, so that the situations of over-cutting, missing cutting and the like in automatic cutting are avoided.)

1. The self-adaptive machining method of the invisible appliance is characterized by comprising the steps of obtaining a dental model, forming an initial dental film on the dental model in a vacuum thermoplastic mode, obtaining a digital model of the initial dental film, generating a cutting curve on the digital model, obtaining an included angle β between a buccal surface and a lingual axis of each tooth, projecting the cutting curve onto a second reference surface by taking a plane with a distance H from the maxillofacial surface as the second reference surface to obtain a projected cutting curve, obtaining intersection points of the first reference surface and the second reference surface on the projected cutting curve for each tooth, taking each intersection point as a key point, setting a space basic cutting angle α, offsetting the projected cutting curve outwards from the lingual surface by L tan (α + β), obtaining an offset cutting curve, subtracting a Z coordinate of the original cutting curve from a Z coordinate of each point on the cutting curve and a Z coordinate of the second reference surface to obtain L, recording key points of each tooth, taking a cutting tool path between a point of a previous tooth and a next tooth as a first cutting tool point, taking a cutting tool point as a falling point on the cutting tool, taking a corresponding falling point on the cutting tool as a falling point, and taking a second cutting tool falling point as a second cutting tool falling point, and taking a corresponding second cutting tool falling point as a second cutting tool falling point, and a second cutting tool falling.

2. The adaptive processing method of the invisible appliance of claim 1, wherein: the acquisition mode of the included angle of the cheek and the tongue to the tooth axis is as follows: projecting the tooth long axis of the tooth position to a first reference surface, making a straight line in the buccal and lingual directions on the first reference surface through the projection line of the tooth long axis, wherein the included angle between the projection line of the tooth long axis and the straight line in the buccal and lingual directions is the included angle between the buccal and lingual axes of the tooth; the first reference plane is the plane through the midpoint of the tooth site and perpendicular to the arch curve.

3. The adaptive processing method of the invisible appliance of claim 2, wherein: the method for acquiring the first reference surface comprises the following steps: and acquiring a middle line of each tooth, taking a midpoint A of the middle line, finding a point B closest to the point A of the tooth on the dental arch curve, and drawing a first reference plane passing through a straight line AB and perpendicular to the dental arch curve.

4. The adaptive processing method of the invisible appliance of claim 3, wherein: the included angle of the buccal and lingual axes in the buccal direction is set as a positive value, and the included angle of the buccal and lingual axes in the lingual direction is set as a negative value.

5. The adaptive processing method of the invisible appliance of claim 1, wherein: the second reference plane is higher than the crown plane of all teeth.

6. The adaptive processing method of the invisible appliance of claim 1, wherein: when the projection cutting curve is biased outwards, the method for determining the bias direction of each point comprises the following steps: each point is provided with two adjacent points which are adjacent in the front and back, a vector is formed by the current point and any one of the adjacent points, each current point is provided with two vectors, an angular bisector of the two vectors is a straight line where the offset direction is located, cross product calculation is carried out on the two vectors to determine the direction of the angular bisector, and the direction of the angular bisector is the offset direction.

7. The adaptive processing method of the invisible appliance of claim 1, wherein: and after obtaining the offset cutting curve, eliminating the selfing area of the offset cutting curve, and operating the key points.

8. The adaptive processing method of the invisible appliance of claim 7, wherein: the self-crossing region of the cutting curve after eliminating the offset adopts the mode that the point which is firstly crossed and the point which is finally crossed in the self-crossing region are obtained, and the point of the middle part is omitted; the corresponding biased outlying point of the drop-off point is replaced by the midpoint of the first and last intersected points.

Technical Field

The invention relates to a method for automatically cutting an invisible appliance in the manufacturing process of the invisible appliance.

Background

The bracket-free invisible appliance is an appliance for correcting the dentognathic deformity by designing and manufacturing a series of ordered transparent movable appliances by means of computer three-dimensional reconstruction, auxiliary diagnosis design technology and computer manufacturing technology and utilizing the resilience force generated by the elastic deformation of the material of the appliances. The tooth correcting device is a continuous and orderly correcting device, and achieves the purpose of tooth correction through continuous small-range tooth movement.

The manufacturing process of the invisible appliance comprises the steps of obtaining oral cavity data of a patient, establishing a three-dimensional model of the oral cavity of the patient according to the oral cavity data, designing an appliance scheme, adjusting a tooth position to be corrected to a target appliance position to obtain a tooth jaw model, generating a cutting line on the tooth jaw model, forming the three-dimensional tooth jaw model into a solid tooth jaw model in a rapid forming mode or a 3D printing mode, covering a film on the solid tooth jaw model by using a vacuum film pressing machine, and cutting or manually polishing the film along the gum line to obtain the invisible appliance. However, in some abnormal teeth protruding particularly to the lingual or labial side, the gum line of the abnormal teeth deviates from the normal arch curve, as shown in fig. 1, and the arch is distorted and cannot be cut or over-cut occurs, thereby causing the invisible appliance to fail to achieve automatic cutting.

Disclosure of Invention

The invention aims to provide an adaptive processing method of an invisible appliance, which can carry out adaptive cutting on the invisible appliance with a dental arch mutation.

The self-adaptive processing method of the invisible appliance comprises the steps of obtaining a dental model, forming an initial dental film on the dental model in a vacuum thermoplastic mode, obtaining a digital model of the initial dental film, generating a cutting curve on the digital model, obtaining a buccal-lingual tooth axis included angle β of each tooth, projecting the cutting curve onto a second reference plane by taking the dental jaw as the lower side and taking a plane with the distance from the dental jaw face as a second reference plane, obtaining intersection points of the first reference plane and the second reference plane on the projected cutting curve for each tooth, taking each intersection point as a key point, setting a space basic cutting angle α, outwards biasing the projected cutting curve along the buccal tongue by L tan (α + β), obtaining a biased cutting curve, subtracting a Z coordinate of an original cutting curve from a Z coordinate of each point on the cutting curve and a Z coordinate of the second reference plane to obtain L, recording key points of each tooth, taking a cutting path between a cutting point of a front tooth and a rear tooth as a linear interpolation point, taking a corresponding cutting tool as a first cutting tool drop point and a second cutting tool drop point, and taking a corresponding second cutting tool drop point on the cutting tool as a second cutting tool drop point, and taking a second cutting tool as a second cutting tool drop point.

The first falling point of the cutter is positioned on a cutting curve, the cutter has a second falling point on a second reference surface, the two points define a straight line and determine the first falling point and the second falling point of the cutter, namely, the form included angle of any point on the cutting line of the cutter can be determined.

Preferably, the acquisition mode of the included angle between the cheek and the tongue to the tooth axis is as follows: projecting the tooth long axis of the tooth position to a first reference surface, making a straight line in the buccal and lingual directions on the first reference surface through the projection line of the tooth long axis, wherein the included angle between the projection line of the tooth long axis and the straight line in the buccal and lingual directions is the included angle between the buccal and lingual axes of the tooth; the first reference plane is the plane through the midpoint of the tooth site and perpendicular to the arch curve.

Preferably, the manner of acquiring the first reference plane is as follows: and acquiring a middle line of each tooth, taking a midpoint A of the middle line, finding a point B closest to the point A of the tooth on the dental arch curve, and drawing a first reference plane passing through a straight line AB and perpendicular to the dental arch curve.

Preferably, the buccal bucco-lingual tooth axis angle is a positive value, and the lingual bucco-lingual tooth axis angle is a negative value.

Preferably, the second reference surface is higher than the top surfaces of all teeth.

Preferably, when the projected cutting curve is biased outwards, the method for determining the bias direction of each point comprises the following steps: each point is provided with two adjacent points which are adjacent in the front and back, a vector is formed by the current point and any one of the adjacent points, each current point is provided with two vectors, an angular bisector of the two vectors is a straight line where the offset direction is located, cross product calculation is carried out on the two vectors to determine the direction of the angular bisector, and the direction of the angular bisector is the offset direction. Each current point is provided with two points which are adjacent in the front and back, the current point forms a unit vector to the adjacent point, each current point is provided with two unit vectors, the sum of the two unit vectors is actually an angular bisector of the angle, the orientation correction of the angular bisector is determined by cross product, particularly for the condition that the three points are collinear, the inner side and the outer side cannot be judged, and the inner side and the outer side can be known only by cross product calculation.

Preferably, after the offset cutting curve is obtained, the selfing area of the offset cutting curve is eliminated first, and then the key points are operated.

Preferably, the selfing region of the cutting curve after eliminating the bias adopts a mode that a point which is intersected firstly and a point which is intersected last in the selfing region are obtained, and a point of a middle part is omitted; the corresponding biased outlying point of the drop-off point is replaced by the midpoint of the first and last intersected points.

The invention has the advantages that: 1. the self-adaptability is good, the cutting angle can be automatically adjusted for the deformed dental film, and the cutting collision is avoided. 2. The cutter track generated by the interpolation operation of the key points can effectively avoid the problem that the C axis of a processing system such as an AC double rotary table is reversed and reversed to influence the processing efficiency, thereby obviously reducing the processing time. 3. The key points can be automatically found according to the characteristics of the teeth, then the difference value is carried out according to the key points, and the inclination angle required by the path is automatically calculated, so that the situations of over-cutting, missing cutting and the like in automatic cutting are avoided.

Drawings

Fig. 1 is a schematic view of a sudden arch change caused by a deformed tooth.

FIG. 2 is a schematic view of a digital model of a dental pellicle.

FIG. 3 is a schematic view of a cut digital model of a dental film.

FIG. 4 is a schematic view of a mid-line of each tooth on the dental model.

FIG. 5 is a schematic representation of a dental arch curve.

Fig. 6 is a schematic view of the long axis of the tooth.

Fig. 7 is a schematic diagram of a projection of a cutting curve on a second reference surface, obtaining a projected cutting curve.

FIG. 8 is a schematic illustration of the determination of bias direction using three points.

FIG. 9 is a schematic of the self-cross region of the biased cut curve.

Fig. 10 is a schematic of the offset cut curve and the projected cut curve of the elimination selfed region.

FIG. 11 is a graphical diagram of the tool rake angle profile for all cutting sites.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings 1 to 11.

The self-adaptive machining method of the invisible appliance comprises the steps of obtaining a dental model, forming an initial dental film on the dental model through vacuum thermal forming, obtaining a digital model of the initial dental film, as shown in fig. 2, generating a cutting curve and a cutting model of the dental film on the digital model, as shown in fig. 3, obtaining a buccal-lingual tooth axis included angle β of each tooth, obtaining a projection cutting curve by projecting the cutting curve onto a second reference plane by taking a plane with a distance H from a dentognathic surface as a second reference plane, obtaining intersection points of the first reference plane and the second reference plane on the projection cutting curve, taking each intersection point as a key point, setting a space base cutting angle α, offsetting the projection cutting curve outwards from the bucco-lingual direction by L tan (α + β), obtaining an offset cutting curve, subtracting a Z coordinate of an original cutting curve from a Z coordinate of each point on the second reference plane on the cutting curve to obtain L, recording key points of each tooth, taking a linear interpolation point between the key point of a previous tooth and the key point of a next tooth as a second cutting tool, and obtaining a point corresponding second cutting point on the cutting plane, and taking a second cutting point as a second cutting plane, and obtaining a second cutting tool.

In some embodiments, the bucco-lingual tooth axis angle is obtained by: projecting the long tooth axis 3 of the tooth position to a first reference surface, and making a straight line in the buccolingual direction on the first reference surface through the projection line of the long tooth axis 3, wherein the included angle between the projection line of the long tooth axis 3 and the straight line in the buccolingual direction is the included angle between the buccolingual direction and the tooth axis; the first reference plane is the plane through the midpoint of the tooth site and perpendicular to the arch curve 2.

The method for acquiring the first reference surface comprises the following steps: obtaining the middle line 1 of each tooth, removing the midpoint A of the middle line 1, finding the point B on the arch curve 2 closest to the point A of the tooth, and drawing a first reference plane passing through the straight line AB and perpendicular to the arch curve 2.

The included angle of the buccal and lingual axes in the buccal direction is set as a positive value, and the included angle of the buccal and lingual axes in the lingual direction is set as a negative value.

In some embodiments, the second reference surface is higher than the top surfaces of all of the teeth.

In some embodiments, after obtaining the biased post-cut curve, the selfed region 6 of the biased post-cut curve is eliminated before operating on the key points.