KR101658113B1 - Method for calculating bending points and angles of orthodontic archwires using computer and program thereof - Google Patents

Abstract

The present invention relates to a method of calculating a bending point and a bend angle of an arch wire for orthodontic use using a computer, and a program thereof. One of the international standard formats for expressing 3D modeling data is an STL (STereoLithography) file that can be stored in a 3D CAD program (E.g., desktop, notebook, tablet PC, etc.), and when the shape of the arch wire is input in the form of STL file, coordinates of the bending point are obtained from the point position data of the arch wire stored in the STL file The length (L) between two consecutive adjacent bending points from the starting end point to the opposite end point of the linear raw material wire used for the production of the arch wire, and After calculating the bending angle? Of the bending point and the angle? In the bending direction of each bending point, And it outputs the bending angle (θ) and a bending direction angle (α) to the arch wire production data.
According to the present invention, by outputting the length L, the bending angle [theta] and the bending direction angle [alpha] as arch wire production data, an arch wire automatic manufacturing apparatus, The wire can be manufactured completely automatically.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of calculating a bending point and a bend angle of an arch wire for orthodontic use using a computer,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for manufacturing an arch wire for orthodontic use, and more particularly, to a method and program for calculating a bending point and a bend angle of an arch wire for orthodontic use using a computer (e.g., a desktop, a notebook PC, .

The general orthodontic procedure determines the shape of the arch wire to be fastened to the bracket corresponding to the position of the orthodontic bracket attached to the tooth from the 3D image obtained by scanning the inside and outside of the patient's teeth with the 3D scanner for orthodontics. This process of orthodontic correction is one of the international standard formats for expressing 3D modeling data, and is performed by using an orthodontic program capable of 3D shape representation as STL (STereoLithography) file which can be stored in 3D CAD program.

FIG. 1 is a 3D image showing the shape of an arch wire determined by performing the conventional orthodontic correction program described above. FIG. 2 is a view showing the arch wire shown in FIG. 1 in 3D coordinates (x, y, z) It is a displayed image.

When the shape of the arched wire is determined by the above-described process, the dental yarn and the dental prosthesis are bent in a straight-line raw material wire used for making the corresponding arched wire while viewing the three-dimensional coordinate image of the arched wire as shown in Fig. Work is done to make arch wire.

In this way, it is impossible to precisely manufacture the arch wire which is manufactured manually by the dentist or the dental technician, and in order to increase the precision when attaching to the bracket, it is subjected to several correction work.

After the revision of the arch wire is completed, it is gradually changed by 7 ~ 8 times of the replacement of the arch wire, although it varies depending on the individual. There is still the inconvenience that a new dentist or a dentist must repeatedly make several corrections manually to produce a new arched wire.

(Patent Document 1) JPP5492965 B2

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a computer (e.g., a desktop, a notebook, and a tablet) capable of reading an STL file used for 3D shape representation in a conventional orthodontic program PC, etc.). When the shape of the arch wire is input in the STL file format, the coordinates of the bending point are sequentially extracted from the point position data of the arch wire stored in the STL file, and the extracted bending point coordinates (L) between adjacent two bending points sequentially from the start end point to the opposite end point of the wire in the form of a straight line used for wire making, the bending angle (?) Of each bending point, After calculating the bending direction angle?, The length L, the bending angle?, And the bending direction angle? Are output to the arch wire fabrication data Is to provide a bending point calculation teeth and bending angle of the orthodontic arch wire for the method using a computer.

Another object of the present invention is to provide a method for calculating a bending point and a bend angle of the arch bridge for orthodontic correction mounted on a computer (e.g., a desktop, a notebook PC, a tablet PC, etc.) And a program for calculating a bending point and a bend angle of an arch wire for orthodontic use using a computer.

According to another aspect of the present invention, there is provided a method of calculating a bending point and a bend angle of an arch wire for orthodontic correction using a computer, the method comprising: a computer (e.g., a desktop, A first step of extracting coordinates of a bending point from the point position data of the arch wire stored in the STL file when the input processing part of the computer inputs the shape of the arch wire into the STL file; Wherein the calculation unit of the computer calculates the distance between the adjacent two bending points sequentially from the start end point to the opposite end point of the linear raw material wire used for producing the arch wire by using the bending point coordinates extracted in the first step (L), a bending angle (?) Of each bending point, and an angle (?) In bending direction of each bending point; And outputting the length (L), the bending angle (?), And the bending direction angle (?) Of the output section of the computer as arch wire production data.

In the first step, the set of triangles constituting the surface of the shape of the arch wire is stored, and the vertex coordinates of each triangle and the angle From the STL file storing a vector (hereinafter referred to as a unit vector) representing a direction perpendicular to the triangle, coordinates of the center point of a triangle having an angle between unit vectors between adjacent triangles greater than 0 are extracted as coordinates of a bending point .

In the second step, two adjacent bending points p0 (x0, y0, z0) and p1 (x1, y1) are sequentially calculated in the bend point and bend angle calculating method of the arch wire for orthodontic use using the computer according to the present invention. characterized in that to obtain equation (1) to between the length (L ₀₎ of the z1).

In the second step, three adjacent bending points p0 (x0, y0, z0) and p1 (x1, y1) are sequentially calculated in the bending point and bending angle calculating method of the arch wire for orthodontic use using the computer according to the present invention. the bending angle? 1 based on the length between p1 and p2 with p1 as the center point with respect to p2 (x2, y2, z2) is calculated from a triangle composed of three points p0, p1, , A is a length between p0 and p2, b is a length between p1 and p2, and c is a length between p0 and p1. &Quot; (2) "

In the second step, three adjacent bending points p0 (x0, y0, z0) and p1 (x1, y1) are sequentially calculated in the bending point and bending angle calculating method of the arch wire for orthodontic use using the computer according to the present invention. (x1, y1, z1), p2 (x2, y2, z2) and p3 (x2, y2, z2), which are successively adjacent to the first plane formed by p2 , y2, and z2) is defined as an angle of bending direction (?) and is defined by the following equation (3). In Equation (3),? is the angle between the unit vectors between the first plane and the second plane Angle.

According to another aspect of the present invention, there is provided a program for calculating a bending point and a bend angle of an arch wire for orthodontic correction using a computer, the program causing a computer to execute the steps 1 to 3 To be stored in the medium.

According to the present invention, when the length L, the bending angle [theta] and the bending direction angle [alpha] are output as the arch wire fabrication data, the arched wire fabrication data, Bending the raw material wire with the bending angle (?) And the bending direction angle (?) Corresponding to the corresponding bending point at successively adjacent bending points from the starting end point to the opposite end point of the raw material wire is automatically performed The precise arch wire can be manufactured completely automatically by utilizing the automatic production of the arch wire which can produce the arch wire.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a 3D image showing the position of a bracket determined by performing a conventional orthodontic program and the shape of an arch wire fastened to a bracket; FIG.
FIG. 2 is an image showing the arch wire shown in the 3D image of FIG. 1 in three-dimensional coordinates. FIG.
3 is a block diagram showing the configuration of a computer for performing a bending point and bend angle calculation method of an arch wire for orthodontic use using a computer according to the present invention.
FIG. 4 is a diagram showing unit vectors of each triangle stored in the STL file. FIG.
FIG. 5 is a diagram for explaining a method of calculating a length L between two neighboring bending points and a bending angle? Of each bending point using bending point coordinates; FIG.
6 is a diagram for explaining a result of calculating a length L between two neighboring bending points and a bending angle? Of each bending point using bending point coordinates;
Fig. 7 is a view for explaining a method of calculating an angle? In bending direction of each bending point; Fig.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 3, the computer 100 for performing the method of calculating the bending point and the bending angle of the arch wire for orthodontic use using the computer according to the present invention includes an STL file used for 3D shape representation in a conventional orthodontic program Readable, and can be a desktop, a notebook, or a tablet PC.

The computer 100 includes an input processing unit 110, an operation unit 120, and an output unit 130.

The input processing unit 110, the operation unit 120, and the output unit 130 are preferably formed of a microprocessor and installed in the computer 100.

When the shape of the arch wire is input in the STL file format, the input processing unit 110 extracts the coordinates of the bending point from the point position data of the arch wire stored in the STL file.

Using the extracted bending point coordinates, the arithmetic unit 120 sequentially calculates the length L between adjacent two bending points from the starting end point to the opposite end point of the linear raw material wire used for the production of the arch wire The bending angle? Of each bending point and the bending direction angle? Of each bending point are calculated.

The output unit 130 outputs the length L, the bending angle? And the bending direction angles? As arch wire production data, and outputs the data in the form of a list, for example.

The method for calculating the bending point and the bend angle of the arch wire for orthodontics by the computer 100 according to the present invention configured as above is performed as follows.

First, when the input processing unit 110 of the computer 100 inputs the shape of the arch wire as an STL file, the coordinates of the bending point are extracted from the point position data of the arch wire stored in the STL file.

At this time, from the STL file storing a set of triangles constituting the surface of the shape of the arch wire and storing a vector (hereinafter referred to as a unit vector) representing the vertex coordinates of each triangle and a direction perpendicular to each triangle, The coordinates of the center point of the triangle having an angle between the unit vectors between the center points of the triangles larger than 0 are extracted as the coordinates of the bending point.

The process of extracting the coordinates of the bending point will be described in more detail as follows.

As mentioned in the prior art, when the shape of the arch wire determined through the orthodontic program in the process of orthodontic correction is displayed as shown in FIGS. 1 and 2, the shape of the corresponding arch wire is used for 3D shape representation STL file.

For reference, the STL file, which is known as one of the international standard formats for representing 3D modeling data, is a file that stores a set of small triangles constituting the surface of a 3D shape, and coordinates the vertex coordinates of each small triangle, Likewise, the unit vector, that is, a vector indicating a direction perpendicular to each small triangle is stored.

When the STL file representing the shape of the arch wire thus stored is input to the input processing unit 110 of the computer 100 according to the present invention, the input processing unit 110 extracts, from the point position data of the arch wire stored in the STL file, The coordinates of the bending point are extracted.

If the shape of the arch wire indicated by the STL file is a straight line shape without a bending point, the directions of the unit vectors are constant.

)는 하기의 수학식4로 나타낸 벡터 간의 내적 공식에 의해 수학식5와 같이 유도하여 구할 수 있다.However, when the shape of the arch wire indicated by the STL file has a bending point, the directions of the unit vectors between adjacent triangles are different with respect to the triangle including the bending point. At this time, the angle between unit vectors between adjacent triangles (

) Can be obtained by the following equation (4) by the inner product formula between the vectors represented by the following equation (4).

,

)의 사이 각도(

)가 0보다 큰 경우 해당 삼각형은 굴곡점이 있는 것으로 판별할 수 있고, 상기 수학식4 및 수학식5를 이용하여 상기 STL에 파일에 저장된 인접한 단위벡터들간의 각도 계산이 완료된 후 0인 데이터를 제거하면 굽힘점들의 좌표만 추출할 수 있게 된다.As shown in Equation (4), the unit vector between two triangles

,

)

) Is greater than 0, it can be determined that the triangle has an inflection point. Using the above Equations (4) and (5), data of zero is calculated after the angle calculation between adjacent unit vectors stored in the file is completed in the STL Only the coordinates of the lower bend points can be extracted.

After the coordinates of the bending point are extracted as described above, the bending point coordinates extracted by the calculation unit 120 of the computer 100 are used to calculate the bending point coordinates from the starting end point of the linear raw material wire used for producing the arch wire, The bending angle? Of each bending point and the bending direction angle? Of each bending point are sequentially calculated between the adjacent two bending points.

The process of calculating the length L between the two bending points, the bending angle? Of each bending point, and the bending angle? Of each bending point will be described in more detail as follows.

As shown in FIG. 2, the resultant values of the input processing unit 110 of the computer 100 are three-dimensional coordinates (x, y, z) of bending points around the reference point.

When the starting end points of the linear raw material wires used for manufacturing the arch wire are denoted by p0 as shown in Fig. 5 and the subsequent bending points are denoted by p1, p2, ... pN in this order, a length L between p0 and p1 ₀ can be calculated by the formula for obtaining the distance between two points in the three-dimensional space, that is, by the above-mentioned equation (1).

The bending angle [theta] 1 based on the length between p1 and p2 with p1 as the center point is obtained from the triangle formed by the three points p0, p1, and p2 by using the cosine second rule, Can be calculated by Equation (2).

FIG. 6 is an example in which the length L between the bending points and the bending angle? Are sequentially calculated for the arch wire shown in FIG.

7 (a), the three points p0, p1 and p2 constitute one plane (the first plane), but the p3 may not be located on the same plane as the plane have. Therefore, in order to determine the bending angle? Of the bending angle? 2 (see FIG. 5) determined by p3, an additional calculation according to Equation (3) described above is required.

Actually, as shown in Fig. 7A, the angle between the first plane consisting of the three points p0, p1 and p2 and the second plane consisting of the points p1, p2 and p3 thereafter, that is, the bending direction angle α), it is possible to know the degree of difference between the planes including the respective bending angles θ.

과

로 나타낼 수 있다. 이 두 벡터 사이의 각도는 상기한 수학식4 및 수학식5와 유사하게 벡터 간의 내적으로부터 구할 수 있며, 그 결과로 구해지는 두 벡터의 사이 각도(β1)는 하기의 수학식6과 같고, 이 두 평면 사이의 틀어짐 각도, 즉 굽힙방향각도(α1)은 180에서 이 두 벡터의 사이 각도(β1)를 뺀 결과가 되며 하기의 수학식7과 같다.A vector perpendicular to each plane is shown in Fig. 7 (b)

and

. The angles between these two vectors can be obtained from the inner product between vectors similar to the above equations (4) and (5), and the angle? 1 between the two vectors obtained as a result is as shown in Equation (6) The angle of divergence between the two planes, that is, the bending direction angle? 1 is obtained by subtracting the angle? 1 between these two vectors at 180, and is expressed by Equation (7).

Thus, when referred to as p0 As shown the starting end of the raw wire in FIG. 5, and then the bend point in order p1, p2, ... pN described above, the length (L ₀ between the one p0 and p1 ) And the bending angle (? 1) and the bending direction angle (? 1) are sequentially performed to the half-end point of the raw material wire, the bending points extracted from the arch wire shape are subjected to the above-described two bending points Both the length L and the bending angle? Of each bending point and the bending direction angle? Of each bending point can be calculated.

After calculating the length L between the two bending points, the bending angle? Of each bending point, and the bending angle? Of each bending point as described above, finally, the output of the computer 100 The portion 130 outputs the length L, the bending angle [theta] and the bending direction angle [alpha] as the arch wire fabrication data.

When the length L, the bending angle [theta] and the bending direction angle [alpha] are output as the arch wire fabrication data according to the embodiment of the present invention described above, Bending the raw material wire with the bending angle (?) And the bending direction angle (?) Obtained corresponding to the corresponding bending point at the next adjacent bending point between the starting end point and the opposite end point of the used raw material wire The precise arch wire can be manufactured completely automatically by utilizing the automatic arch wire manufacturing device which can automatically produce the arch wire by the mechanical automatic operation.

The method and program for calculating the bending point and the bend angle of the arch wire for orthodontic use using the computer according to the present invention described above are not limited to the embodiments described above and are deviated from the gist of the present invention claimed in the claims It is the technical spirit of the present invention to the extent that any person skilled in the art to which the present invention belongs can make various changes.

100: computer 110: input processor
120: Operation unit 130:

Claims (10)

Performed by a computer capable of reading STL (STereoLithography) files,
A first step of extracting coordinates of a bending point from the point position data of the arch wire stored in the STL file when the shape of the arch wire is inputted in the form of an STL file;
The length L between the adjacent two bending points sequentially from the starting end point to the opposite end point of the linear raw material wire used for manufacturing the arch wire by using the bending point coordinates extracted in the first step, A second step of calculating a bending angle? Of the bending point and an angle? In bending direction of each bending point;
A third step of outputting the length L, the bending angle [theta] and the bending direction angle [alpha] to the arch wire fabrication data;
And calculating a bending point and a bend angle of the arch wire for orthodontic use using the computer. 2. The method according to claim 1, wherein in the first step,
A STL file storing a set of triangles constituting the surface of the shape of the arch wire and storing a vector indicating a vertex coordinate of each triangle and a direction perpendicular to each triangle (hereinafter referred to as a unit vector) Wherein the coordinate of the center point of the triangle having the angle between the unit vectors larger than 0 is extracted as the coordinates of the bending point. The method according to claim 1, wherein in the second step,
Equation to the length (L ₀₎ between the two bending points p0 (x0, y0, z0) neighboring sequential, p1 (x1, y1, z1 )

And calculating a bending point and a bend angle of the arch wire for orthodontic use using the computer. The method according to claim 1, wherein in the second step,
A bending angle? 1 based on the length between p1 and p2 with p1 as a center point with respect to successively adjacent three bending points p0, p1 and p2 is obtained from a triangle composed of three points p0, p1 and p2, The following equation

Wherein a is a length between p0 and p2, b is a length between p1 and p2, and c is a length between p0 and P1. Computation of bending point and bending angle of arch wire for orthodontic correction Way. The method according to claim 1, wherein in the second step,
The angle between the first plane formed by the three adjacent bending points p0, p1, and p2 and the second plane formed by the three bending points p1, p2, and p3, And the following equation

, Wherein? Is an angle between a unit vector between the first plane and the second plane. A computer-implemented method for calculating a bending point and a bend angle of an arch wire for orthodontic correction. Combined with a computer capable of reading STL (STereoLithography) files,
A first step of extracting coordinates of a bending point from the point position data of the arch wire stored in the STL file when the shape of the arch wire is inputted in the form of an STL file;
The length L between the adjacent two bending points sequentially from the starting end point to the opposite end point of the linear raw material wire used for manufacturing the arch wire by using the bending point coordinates extracted in the first step, A second step of calculating a bending angle? Of the bending point and an angle? In bending direction of each bending point;
A third step of outputting the length L, the bending angle [theta] and the bending direction angle [alpha] to the arch wire fabrication data;
Wherein the bending point and the bend angle of the arch wire for orthodontic use using a computer are stored in the medium so as to execute the program. 7. The method of claim 6,
A STL file storing a set of triangles constituting the surface of the shape of the arch wire and storing a vector indicating a vertex coordinate of each triangle and a direction perpendicular to each triangle (hereinafter referred to as a unit vector) Wherein the coordinates of the center point of the triangle having the angle between the unit vectors larger than 0 are stored in the medium for extracting the coordinates of the center point of the triangle with coordinates of the bending point. 7. The method of claim 6,
Equation to the length (L ₀₎ between the two bending points p0 (x0, y0, z0) neighboring sequential, p1 (x1, y1, z1 )

A program for calculating a bending point and a bend angle of an arch wire for orthodontic use using a computer. 7. The method of claim 6,
A bending angle? 1 based on the length between p1 and p2 with p1 as a center point with respect to successively adjacent three bending points p0, p1 and p2 is obtained from a triangle composed of three points p0, p1 and p2, The following equation

(Where a is the length between p0 and p2, b is the length between p1 and p2, and c is the length between p0 and p1)
Of the arch wire for orthodontic use using a computer, characterized in that it is stored in the medium to obtain the bending point and bend angle of the arch wire for orthodontic use. 7. The method of claim 6,
The angle between the first plane formed by the three adjacent bending points p0, p1, and p2 and the second plane formed by the three bending points p1, p2, and p3, And the following equation

(Where beta is an angle between unit vectors between the first plane and the second plane)
A program for calculating a bending point and a bend angle of an arch wire for orthodontic use using a computer.

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