阅读说明：本技术 一种u型槽牙托槽及其客制化的成型方法 (U-shaped groove denture groove and customized forming method thereof ) 是由 李俊 庄加福 杨林杰 高银 白成云 陈军希 于 2020-04-03 设计创作，主要内容包括：本发明一种U型槽牙托槽及其客制化的成型方法,结合UG强大的二次开发功能,将牙曲面的提取、牙托槽在牙曲面的定位、牙托槽的参数调整整合在一个交互平台上,解决传统建模过程的平台切换、数据导入等问题,简化了传统的基于三维软件的设计生产方式,利用UG技术给出一种个性化、精密度更高、底板更吻合的牙托槽模板的设计方法,为正畸临床提供更好的技术支持,并提升了牙托槽建模的工作效率,让个性化的牙托槽建模成为可能,对制造业企业提升生产效率、降低人力成本具有重要意义。(The invention provides a U-shaped groove denture trough and a customized forming method thereof, which combine the powerful secondary development function of UG, integrate the extraction of a tooth curved surface, the positioning of the denture trough on the tooth curved surface, and the parameter adjustment of a denture trough on an interactive platform, solve the problems of platform switching, data import and the like in the traditional modeling process, simplify the traditional design and production mode based on three-dimensional software, provide a design method of a denture trough template which is personalized, has higher precision and more consistent bottom plate by utilizing UG technology, provide better technical support for orthodontic clinic, improve the working efficiency of denture trough modeling, enable the personalized denture trough modeling to become possible, and have important significance for improving the production efficiency and reducing the labor cost of manufacturing enterprises.)

1. The utility model provides a U type groove tooth holds in palm groove, mainly includes a support groove body, its characterized in that: the upper end surface of the bracket body is provided with a groove for the arch wire to pass through, and the groove is horizontally opened towards the labial cheek, so that the arch wire can be smoothly put into the groove from the labial cheek surface to apply force; the two sides of the bracket body are respectively provided with a bracket wing for ligating and fixing the arch wire, the two bracket wings are U-shaped grooves, the lower end of the bracket body is a substrate, and the contact surface of the substrate and the tooth surface is matched with the shape of the buccal and labial surfaces of all teeth.

2. The U-shaped slot bracket of claim 1, wherein: the lower surface of the substrate is provided with an array cylinder.

3. The U-shaped slot bracket of claim 1, wherein: side holes for fixing the arch wire are respectively arranged on the two bracket wings on the upper surface side of the bracket body.

4. The U-shaped slot bracket of claim 1, wherein: the middle part of the groove is provided with a concave position which is concave and occupies about the length of the groove 1/3, when the arch wire is fixed, the concave position is not contacted with the arch wire, and the contact part of the concave position and the arch wire is only two ends of the groove.

5. The customized forming method of the U-shaped slot bracket as claimed in claim 1, which comprises the following steps:

step 1, constructing the whole denture socket template by adopting a parameterization mode:

designing various molding characteristics of a denture socket template on a block entity, and then constructing a target entity on the block entity in a key slot mode, a pattern drawing mode, a hole mode and a stretching mode;

step 2, representing various types of denture socket templates through a prt engineering file of UG and storing the denture socket templates in an interactive platform;

step 3, determining the position of the denture groove by an interactive method

Acquiring a CT scanning file of a patient tooth from an interactive platform and converting the CT scanning file into an ST L file, opening a tooth model corresponding to the ST L file in a three-dimensional software environment and picking up a tooth curved surface of a target, then selecting a point on the tooth curved surface by using a mouse as an origin of a default denture socket template, establishing a denture socket coordinate system on the origin, and further converting the coordinates of the tooth curved surface into the denture socket coordinate system;

step 4, after the coordinate conversion of the tooth curved surface is finished, extracting tooth curved surface point cloud data of a user in a denture groove coordinate system, wherein the point cloud data comprises basic geometric information of the tooth curved surface and information of the position, the posture and the position of the tooth curved surface and a denture groove, and generating a trimming patch according to the point cloud data;

step 5, opening a corresponding prt file according to the type of the selected denture socket template from the interactive platform, extracting all features in the prt file, namely obtaining a parameter list of the prt file, adjusting the whole or local parameters of the denture socket template by using an attribute dialog box in an interactive mode by a user, calling UG to generate the prt file of a new denture socket template on the premise that the system judges that the adjusted parameters are legal, and realizing quick modification, quick generation and quick display of the denture socket template;

step 6, once the tooth curved surface point cloud data and the type of the tooth socket template are determined, trimming the base of the tooth socket template by using the tooth curved surface through a fitting algorithm, so that the tooth socket base trimmed through the trimming process can be accurately matched with the tooth curved surface, and finally generating a tooth socket;

and 7, exporting the finally generated dental bracket into stl files, and performing subsequent model browsing or model printing.

6. The customized forming method for the U-shaped slot bracket as claimed in claim 5, wherein the step 1 is to construct the whole bracket template in a parameterization manner, design various forming features of the bracket template on the block entity, and then construct the target entity on the block entity in a keyway, pattern drawing, hole and stretching manner, specifically:

(1) setting the length, width and height parameters of the block which can be changed within a certain constraint range by comprehensively considering the shape and structural stability of the teeth;

(2) set up the degree of depth and the width parameter of groove, can adjust according to the demand of horizontal arch wire:

(3) setting the angle of a drawing die;

(4) setting the height, depth and corners of a U-shaped groove of a bracket wing for winding and fixing a horizontal arch wire;

(5) the height of the base of the denture groove can be fixed, and in order to achieve enough bonding strength, enough bonding area and base height need to be ensured;

(6) edge rounding is arranged on the sharp edge;

(7) and all parameters are uniformly and correlatively set, so that the whole size control of the denture socket template is realized.

7. The method for custom forming a U-shaped slot bracket as claimed in claim 5, wherein the step 3 comprises the following steps:

(1) picking up a plurality of target tooth curved surfaces of interest on the tooth model through an interactive method;

(2) selecting a window coordinate W by a mouse (W)_x,w_y) A denture socket model vertex P (u) obtained by intersection of a ray intersection algorithm and the denture socket template_x,u_y,u_z)；

(3) After the vertex P of the denture socket template is obtained, a normal vector n (n) of the vertex of the denture socket template is estimated by adopting a normal vector estimation algorithm based on knn_x,n_y,n_z) As the z-axis of the denture socket template coordinate system;

(4) normal vector n (n) at the top of the estimated denture socket template_x,n_y,n_z) Then, the y-axis direction vector y of the denture socket template coordinate system_b(y_bx,y_by,y_bz) From the x-axis direction vector x (x) of the world coordinate system_x,x_y,x_z) Z-axis direction vector n (n) of the denture socket template coordinate system_x,n_y,n_z) Form a cross product of y_b＝x×n；

(5) Direction vector x of x-axis of denture socket template coordinate system_b(x_xb,x_yb,x_zb) The direction vector by of the y axis of the denture socket template coordinate system and the direction of the z axisBx is by × n, thus forming a default denture trough coordinate system;

(6) after a coordinate system of the dental bracket is established, converting the data of the tooth curved surface into the data under the coordinate system of the dental bracket:

the origin of the denture trough coordinate system under the world coordinate system is P (u)_x,u_y,u_z) The direction vectors of the x, y and z axes are bx, by and n respectively, the coordinate t of any vertex on the tooth curved surface under the world coordinate system is transformed, and the coordinate t under the denture trough coordinate system is_bThis can be solved by:

Technical Field

The invention relates to a U-shaped groove denture base groove and a customized forming method thereof.

Background

Currently, single tooth data is generally imported into three-dimensional design software such as UG, Imageware, Geomagic studio and Mimics, and three-dimensional design and construction are carried out by combining with a denture socket template. Traditional denture base groove design flow: (1) extracting point cloud data of a single tooth and importing the point cloud data into three-dimensional modeling software; (2) generating a curved surface of the point cloud model; (3) and trimming the denture socket template by the curved surface to generate the denture socket with the attached tooth surface. There are several major problems with this design process: first, generally, only a single tooth can be treated at a time with one project document; secondly, the position and the direction of the bracket on the curved surface are determined in advance and are not easy to adjust; thirdly, the overall size and local structure of the bracket are adjusted fussy. This design flow requires switching over on multiple platforms, and is long and cumbersome in design time.

Object of the Invention

The invention aims to provide a U-shaped groove denture trough and a customized forming method thereof, which simplify the traditional design and production mode based on three-dimensional software, provide a design method of a denture trough template with individuation, higher precision and more consistent bottom plate by utilizing UG technology, provide better technical support for orthodontic clinic, improve the working efficiency of denture trough modeling, enable the individualized denture trough modeling to become possible, and have important significance for improving the production efficiency and reducing the labor cost of manufacturing enterprises.

The invention relates to a U-shaped groove tooth bracket which mainly comprises a bracket body, wherein the upper end surface of the bracket body is provided with a groove for an arch wire to pass through, and the groove is horizontally opened from the labial cheek, so that the arch wire can be smoothly put in from the labial cheek to apply force; the two sides of the bracket body are respectively provided with a bracket wing for ligating and fixing the arch wire, the two bracket wings are U-shaped grooves, the lower end of the bracket body is a substrate, and the contact surface of the substrate and the tooth surface is matched with the shape of the buccal and labial surfaces of all teeth.

The lower surface of the substrate is provided with an array cylinder.

Side holes for fixing the arch wire are respectively arranged on the two bracket wings on the upper surface side of the bracket body.

The middle part of the groove is provided with a concave position which is concave and occupies about the length of the groove 1/3, when the arch wire is fixed, the concave position is not contacted with the arch wire, and the contact part of the concave position and the arch wire is only two ends of the groove.

The customization forming method of the U-shaped slot tooth bracket comprises the following steps:

step 1, constructing the whole denture socket template by adopting a parameterization mode:

designing various molding characteristics of a denture socket template on a block entity, and then constructing a target entity on the block entity in a key slot mode, a pattern drawing mode, a hole mode and a stretching mode;

step 2, representing various types of denture socket templates through a prt engineering file of UG and storing the denture socket templates in an interactive platform;

step 3, determining the position of the denture groove by an interactive method

Acquiring a CT scanning file of a patient tooth from an interactive platform and converting the CT scanning file into an ST L file, opening a tooth model corresponding to the ST L file in a three-dimensional software environment and picking up a tooth curved surface of a target, then selecting a point on the tooth curved surface by using a mouse as an origin of a default denture socket template, establishing a denture socket coordinate system on the origin, and further converting the coordinates of the tooth curved surface into the denture socket coordinate system;

step 4, after the coordinate conversion of the tooth curved surface is finished, extracting tooth curved surface point cloud data of a user in a denture groove coordinate system, wherein the point cloud data comprises basic geometric information of the tooth curved surface and information of the position, the posture and the position of the tooth curved surface and a denture groove, and generating a trimming patch according to the point cloud data;

step 5, opening a corresponding prt file according to the type of the selected denture socket template from the interactive platform, extracting all features in the prt file, namely obtaining a parameter list of the prt file, adjusting the whole or local parameters of the denture socket template by using an attribute dialog box in an interactive mode by a user, calling UG to generate the prt file of a new denture socket template on the premise that the system judges that the adjusted parameters are legal, and realizing quick modification, quick generation and quick display of the denture socket template;

step 6, once the tooth curved surface point cloud data and the type of the tooth socket template are determined, trimming the base of the tooth socket template by using the tooth curved surface through a fitting algorithm, so that the tooth socket base trimmed through the trimming process can be accurately matched with the tooth curved surface, and finally generating a tooth socket;

and 7, exporting the finally generated dental bracket into stl files, and performing subsequent model browsing or model printing.

Step 1 in adopt the parameterization mode to construct whole denture socket template, design the various shaping characteristics of denture socket template on the block entity, then construct the target entity through keyway, pattern drawing, hole, tensile mode on the block entity, specifically do:

(1) setting the length, width and height parameters of the block which can be changed within a certain constraint range by comprehensively considering the shape and structural stability of the teeth;

(2) set up the degree of depth and the width parameter of groove, can adjust according to the demand of horizontal arch wire:

(3) setting the angle of a drawing die;

(4) setting the height, depth and corners of a U-shaped groove of a bracket wing for winding and fixing a horizontal arch wire;

(5) the height of the base of the denture groove can be fixed, and in order to achieve enough bonding strength, enough bonding area and base height need to be ensured;

(6) edge rounding is arranged on the sharp edge;

(7) and all parameters are uniformly and correlatively set, so that the whole size control of the denture socket template is realized.

The step 3 specifically comprises the following steps:

(1) picking up a plurality of target tooth curved surfaces of interest on the tooth model through an interactive method;

(2) selecting a window coordinate W by a mouse (W)_x,w_y) A denture socket model vertex P (u) obtained by intersection of a ray intersection algorithm and the denture socket template_x,u_y,u_z)；

(3) After the vertex P of the denture socket template is obtained, a normal vector n (n) of the vertex of the denture socket template is estimated by adopting a normal vector estimation algorithm based on knn_x,n_y,n_z) As the z-axis of the denture socket template coordinate system;

(4) normal vector n (n) at the top of the estimated denture socket template_x,n_y,n_z) Then, the y-axis direction vector y of the denture socket template coordinate system_b(y_bx,y_by,y_bz) From the x-axis direction vector x (x) of the world coordinate system_x,x_y,x_z) Z-axis direction vector n (n) of the denture socket template coordinate system_x,n_y,n_z) Form a cross product of y_b＝x×n；

(5) Direction vector x of x-axis of denture socket template coordinate system_b(x_xb,x_yb,x_zb) Bx is by × n, thus forming a default denture socket coordinate system;

(6) after a coordinate system of the dental bracket is established, converting the data of the tooth curved surface into the data under the coordinate system of the dental bracket:

the origin of the denture trough coordinate system under the world coordinate system is P (u)_x,u_y,u_z) The direction vectors of the x, y and z axes are bx, by and n respectively, the coordinate t of any vertex on the tooth curved surface under the world coordinate system is transformed, and the coordinate t under the denture trough coordinate system is_bThis can be solved by:

the invention realizes the positioning of the denture trough by an interactive method, and picks up a plurality of tooth curved surfaces by a three-dimensional picking method: firstly, determining the position of a tooth bracket on a tooth curved surface by a three-dimensional point picking method, then primarily determining a tooth bracket coordinate system by curved surface normal vector estimation and PCA principal component analysis algorithm, and then converting curved surface point cloud to the tooth bracket coordinate system.

In order to simplify the adjustment of the whole size and the local structure of the dental tray groove, all important parameters are extracted to form a parameterized list of the dental tray groove, and the adjustment is carried out through interactive software and an attribute option dialog box.

On the basis, the powerful secondary development function of UG is combined, the forming method for customizing the U-shaped groove and the denture trough integrates extraction of a tooth curved surface, positioning of the denture trough on the tooth curved surface, and parameter adjustment of the denture trough on an interactive platform, solves the problems of platform switching, data import and the like in the traditional modeling process, and improves the modeling efficiency.

Drawings

1(a) -1 (h) are schematic diagrams of UG-based dental tray template modeling processes;

FIG. 2 is a schematic view of the tooth flank mating in the present invention;

FIG. 3 is a schematic view of the present invention for picking up a plurality of tooth surfaces;

FIG. 4 is a schematic view of an interactive interface for adjusting tooth surface fit parameters in accordance with the present invention;

FIG. 5 is a flow chart of the present invention for trimming a dental socket template for a dental surface;

FIG. 6(a) is a schematic view of a tooth surface according to the present invention;

FIG. 6(b) is a schematic point cloud of the tooth surface of the present invention;

FIGS. 7(a) and (b) are schematic views of a tray slot created by trimming according to the present invention;

fig. 8(a) and (b) are schematic views of the finished denture trough printed by using a common 3D printer according to the present invention.

Detailed Description

Personalized tray socket generation involves mainly three parts: the tooth support groove template, the position and the direction of the tooth support groove on the tooth curved surface and the parameters of the tooth support groove.

The invention provides a structure of a U-shaped groove bracket and a parameter representation method thereof in an embodiment, and the representation method is not only specific to the U-shaped groove bracket, but also applicable to parametric representation of other types of brackets.

As shown in fig. 7(a)7(b), the U-shaped slot bracket of the present invention mainly comprises a bracket body 1, wherein a slot 2 for an arch wire to pass through is arranged on the upper end surface of the bracket body 1, and the slot 2 is horizontally opened from the labial surface to the buccal surface, so that the arch wire can be smoothly put into the bracket from the labial surface and applied with force; the two sides of the bracket body 1 are respectively provided with a bracket wing 3 for ligating and fixing an arch wire, the two bracket wings 3 are U-shaped grooves, the two bracket wings 3 are respectively positioned on the upper surface side of the bracket body 1 and are provided with side holes 4 for fixing the arch wire, the lower end of the bracket body 1 is a substrate 5, the lower surface of the substrate 5 is provided with an array cylinder 6, and the contact surface 61 of the array cylinder 6 and the tooth surface is matched with the buccal labial surface shape of each tooth.

In order to reduce the friction between the arch wire and the dental bracket, the middle part of the groove is provided with a concave position which is concave and occupies about the length of the groove 1/3, when the arch wire is fixed, the concave position is not contacted with the arch wire, and the contact parts with the arch wire are only two ends of the groove.

As shown in fig. 5, the forming method for customizing the U-shaped groove denture base groove comprises the following steps:

step 1, constructing the whole denture socket template by adopting a parameterization mode:

there are two categories of dental brackets: one is realized the self-ligating bracket fixed to the arch wire through the sliding closure, and its second is realized the wire winding type bracket fixed to the arch wire through the wire winding, contains three basic component parts usually: base, slot, support groove wing.

Substrate (blacket base): the shape of the tooth-supporting base is designed to be mainly used for enhancing the bonding force with the tooth surface, the shape of the contact surface of the base and the tooth surface is matched with the shape of the lip and cheek of each tooth, the tooth-supporting base is provided with a metal grid, a cylindrical array or an etched bottom plate, and the base enables the denture groove to be firmly bonded on the tooth surface through an adhesive;

slot (blacket slot): the arch wire is horizontally opened towards the labial and buccal surfaces, so that the arch wire can be smoothly put in and applied force from the labial and buccal surfaces;

slot wing (bracket wing): the arch wire is convenient to ligate and fix, the wings can be attached with drag hooks for traction, and the bracket can be divided into single wing, double wings and three wings according to the wing shape of the bracket.

The invention adopts a parameterization mode to construct the whole denture socket template, designs various forming characteristics of the denture socket template, such as key slots, holes, array cylinders and the like, on a block entity, and then constructs a target entity on the block entity through the key slots, the pattern drawing, the holes, the stretching, the array and the like:

(1) setting a length (base _ L) width (base _ W) height (base _ H) parameter of a block which can be changed within a certain constraint range, considering the stability of the shape and structure of the tooth, as shown in fig. 1-a;

(2) the depth (retslot _ hreate) and width (retslot _ rate) parameters of the groove are set, and can be adjusted according to the requirements of the horizontal arch wire:

as orthodontic archwires are of many kinds, the cross-sectional shapes of the archwires are divided into: have round silk (the cross section is circular), square silk (the cross section is rectangle or square), twist silk (twist together by stranded archwire and synthesize, like the fried dough twist), divide from the archwire cross section diameter: there are 0.012, 0.014, 0.016, 0.018, 0.020, (hereinafter square silk) 0.016 x 0.016, 0.017 x 0.022, 0.017 x 0.025, 0.018 x 0.025, 0.019 x 0.025, 0.0215 x 0.028. (unit: inch), different archwires have different depth and width requirements for the slot, and thus this parameter is adjustable.

In the embodiment, a square wire arch wire is taken as an example to design a groove, as shown in figure 1-b; because the groove is used for fixing the arch wire, the width can be modified (generally more than 400 mu m), in order to reduce the friction between the arch wire and the bracket, the middle part of the groove is provided with a concave position which occupies about the length 1/3 of the groove and is concave, when the arch wire is fixed, the concave position is not contacted with the arch wire, and the contact parts with the arch wire are only two ends of the groove;

(3) setting the angle draft _ angle of the draft:

the main purpose of the drawing is to form a force which is slowly changed up and down, and generally speaking, the angle of the drawing is between 3 degrees and 8 degrees, as shown in fig. 1-c;

(4) the bracket wing U-shaped slot height (uslot _ dry), depth (uslot _ rate), and corner (uslot _ rate) configured to wrap and secure a horizontal archwire is shown in fig. 1-d;

(5) the diameter (simhole _ rate) and depth (simhole _ rate) of the two side holes of the bracket wings provided for better retention of the archwire, as shown in fig. 1-e;

(6) the denture groove base surface is provided with an array cylinder, the depth (chassis _ depth) of the base, the wall width (chassis _ limit), the height (cylinder _ h) of the cylinder and the diameter (cylinder _ radius) of the cylinder are set, so that the contact surface of the array cylinder and the tooth surface is matched with the shape of the labial and buccal surfaces of all teeth, as shown in fig. 1-f;

the height of the base of the denture base can be fixed, but the problems of unevenness and inclination of the tooth surface can be considered, and in order to achieve enough fitting strength, enough fitting area and base height are ensured. The shape of the base surface is generally rectangular, and shapes such as an ellipse can be preset, so that the length and the width of the rectangle can be modified according to different tooth surfaces.

(7) Edge rounding is arranged, and edge chamfering is carried out on sharp edges to improve the softness of the sharp edges, as shown in figures 1-g and 1-h;

(8) controlling the overall size of the denture socket template:

all parameters are uniformly and correlatively set, so that the overall dimension control of the denture trough template is realized, for example, when the height of the upper half part of the denture trough body is adjusted, the depth of the trough can be randomly changed;

step 2, representing various types of denture socket templates through a prt engineering file of UG and storing the denture socket templates in an interactive platform;

step 3, determining the position of the denture groove by an interactive method

Tooth surface matching is an important component of the invention, and is related to the positioning accuracy and structure generation of the denture trough on the tooth surface. The bracket can be inclined and rotated on the tooth surface, and the height position of the bracket can be adjusted, as shown in figure 2.

The method comprises the following steps of obtaining a CT scanning file of a patient tooth from an interactive platform and converting the CT scanning file into an ST L file, opening a tooth model corresponding to the ST L file in a three-dimensional software environment and picking up a target tooth curved surface, then using a mouse to select a point on the tooth curved surface as an origin of a default denture base template, establishing a denture base coordinate system on the origin, and further converting coordinates of the tooth curved surface into the denture base coordinate system, and specifically comprises the following steps:

(1) picking up a plurality of target tooth curved surfaces of interest on the tooth model by an interactive method, as shown in fig. 3;

(2) selecting a window coordinate W on a two-dimensional screen by a mouse (W)_x,w_y) A denture socket model vertex P (u) obtained by intersection of a ray intersection algorithm and the denture socket template_x,u_y,u_z)；

(3) After the vertex P of the denture socket template is obtained, a normal vector n (n) of the vertex of the denture socket template is estimated by adopting a normal vector estimation algorithm based on knn_x,n_y,n_z) Z-axis as denture socket template coordinate system:

firstly, selecting a peak P of a denture socket template based on k (k) of Euclidean distance>3) vertices Q₁,Q₂…Q_kThe coordinates thereof are respectively (v)_x1,v_y1,v_z1),(v_x2,v_y2,v_z2)…(v_xk,v_yk,v_zk) Normal vector n andshould be minimal, i.e. the sum of squared dot products ofDirectly solving by using a least square algorithm;

(4) normal vector n (n) at the top of the estimated denture socket template_x,n_y,n_z) Then, the y-axis direction vector y of the denture socket template coordinate system_b(y_bx,y_by,y_bz) From the x-axis direction vector x (x) of the world coordinate system_x,x_y,x_z) Z-axis direction vector n (n) of the denture socket template coordinate system_x,n_y,n_z) Form a cross product of y_b＝x×n；

(5) Direction vector x of x-axis of denture socket template coordinate system_b(x_xb,x_yb,x_zb) Bx is by × n, thus forming a default denture socket coordinate system;

(6) after a coordinate system of the dental bracket is established, converting the data of the tooth curved surface into the data under the coordinate system of the dental bracket:

the origin of the denture trough coordinate system under the world coordinate system is P (u)_x,u_y,u_z) The direction vectors of the x, y and z axes are bx, by and n respectively, the coordinate t of any vertex on the tooth curved surface under the world coordinate system is transformedCoordinate t in the denture trough coordinate system_bThis can be solved by:

if the parameters of the tray slot coordinate system and the tooth surface are to be adjusted, the adjustment can be performed using the interactive ball and the orientation control, as shown in fig. 4.

Step 4, after the coordinate conversion of the tooth curved surface is completed, extracting tooth curved surface point cloud data of a user in a denture base slot coordinate system, wherein the point cloud data comprises basic geometric information of the tooth curved surface and information of the position, the posture and the position of the tooth curved surface and a denture base, and generating a trimming patch according to the point cloud data, as shown in fig. 6;

step 5, opening a corresponding prt file according to the type of the selected denture socket template from the interactive platform, extracting all features in the prt file, namely obtaining a parameter list of the prt file, adjusting the whole or local parameters of the denture socket template by using an attribute dialog box in an interactive mode by a user, calling UG to generate the prt file of a new denture socket template on the premise that the system judges that the adjusted parameters are legal as shown in figure 4, and realizing quick modification, quick generation and quick display of the denture socket template;

step 6, once the tooth curved surface point cloud data and the type of the tooth socket template are determined, trimming the base of the tooth socket template by using the tooth curved surface through a fitting algorithm, so that the tooth socket base trimmed through the trimming process can be accurately matched with the tooth curved surface, and finally generating a tooth socket, as shown in fig. 7;

the basic flow of the fitting algorithm is as follows:

1) converting the tooth curved surface point cloud data into sheet bodies to generate trimming surface patches;

2) generating a base array cylinder of the denture groove template;

3) pruning is achieved through model boolean operations.

And 7, exporting the finally generated dental bracket into an stl file, and performing subsequent model browsing or model printing, wherein the model is a real model printed by a common 3D printer as shown in FIG. 8.

The parameter setting and extraction in the prt file are a key point. For each parameter, describing and distinguishing the parameter by using 'tag: identification, Name: Name, expression, Val: value, units: unit, type: category, Desc: description, lhs: expression left formula and rhs expression right formula', so that the generation of the whole bracket template can be changed by changing a plurality of parameter values.

Conventional bracket creation requires that the position of the bracket on the curved surface of the tooth be predetermined and difficult to adjust once determined. In addition, the overall size and the local structure of the denture groove need to be adjusted through an expression module built in software, parameters are multiple and dispersed, searching is inconvenient, and the process is complicated.

The invention realizes the positioning of the denture trough by an interactive method, and picks up a plurality of tooth curved surfaces by a three-dimensional picking method: firstly, determining the position of a bracket on a tooth curved surface by a three-dimensional point picking method, then primarily determining a tooth bracket coordinate system by curved surface normal vector estimation and PCA principal component analysis algorithm, and then converting curved surface point cloud to the tooth bracket coordinate system.

In order to simplify the adjustment of the whole size and the local structure of the dental tray groove, all important parameters are extracted to form a parameterized list of the dental tray groove, and the adjustment is carried out through an interactive control and a property option dialog box.

On the basis, by combining the powerful secondary development function of UG, the extraction of the tooth curved surface, the positioning of the denture groove on the tooth curved surface and the parameter adjustment of the denture groove are integrated on an interactive platform, so that the problems of platform switching, data import and the like in the traditional modeling process are solved, and the modeling efficiency is improved.

As described above, the technical scope of the present invention is not limited, and therefore, any minor modifications, equivalent changes and modifications made to the above embodiments according to the technical spirit of the present invention are within the scope of the technical solution of the present invention.