Jaw position analysis system and method based on X-ray skull side position film

Abstract

The invention discloses a jaw position analysis system and method based on an X-ray skull side position film. The jaw position analysis system based on the X-ray skull side position film comprises an X-ray skull side position film tracing program module, a condyle process central point calculation program module, a condyle process central point offset program module, a dental crown segmentation projection program module, a dental crown projection coincidence program module, a registration program module, a condyle process coordinate system generation program module and a matrix calculation program module. According to the jaw position analysis method, jaw position analysis can be completed only through an X-ray skull side position sheet and upper and lower jaw three-dimensional tooth models of CR and ICP positions used in conventional orthodontic examination and analysis, a plaster model and a traditional jaw frame are not needed, and great convenience is brought to screening of jaw position abnormity by clinicians; an orthodontic doctor is assisted to carry out better scheme design, possible temporal-mandibular joint problems are prevented, and the correction result is more stable.

Description

Technical Field

[0001] The present invention relates to the field of dental orthodontics, and in particular to a jaw position analysis system and method based on X-ray lateral cephalogram. Background Art

[0002] Temporomandibular joint disorder is a common disease caused by a variety of factors, among which the most important and direct factor is the displacement of the mandible caused by malocclusion, which causes the condyle to hit the fossa, resulting in symptoms such as snapping and pain in the temporomandibular joint. The temporomandibular joint is a complex joint. The mandible connects the teeth and condyle into a whole. The left and right temporomandibular joints can complete complex occlusal movements. Jaw position usually refers to the position of the mandible under different tooth occlusion conditions. From a professional perspective, there are two commonly used jaw positions. One is the centric relationship position (abbreviated as CR position), which refers to the position of the mandible relative to the maxilla when the condyle is located in the most anterior and superior position in the fossa and the condyle is facing the posterior slope of the articular tubercle. At this time, the mandible can perform a simple hinge rotation, and the condyle and fossa can resist the maximum contraction force of the jaw lifting muscles without any discomfort. It is a stable position with good repeatability. One is the intercuspal position (ICP), which refers to the position of the mandible when the cusps and fossae of the upper and lower teeth are in the widest and most stable contact. Some scholars also call it the maximum intercuspal position (MI, MIC, MIP), which is a common position during chewing.

[0003] ICP is relatively easy to determine clinically, which is the position of the mandible where the upper and lower teeth are in the widest contact during chewing. To confirm the CR position clinically, it is usually necessary to have the patient repeatedly do small mouth opening exercises, and use bite records to obtain the position of the mandible when the upper and lower teeth do not come into contact. The most ideal occlusal state is when the CR position coincides with the ICP position.

[0004] Literature reports show that the incidence of inconsistency between ICP and CR is very high. For orthodontists, the severity of jaw deviation needs to be assessed before starting treatment. During correction, it is necessary to consider adjusting the position of the teeth as much as possible to reduce the deviation rather than aggravate it.

[0005] In the past, jaw position analysis required the use of a face bow to transfer the positional relationship between the condyle and the maxillary tooth model, and then placing the plaster model on a specially designed jaw frame for analysis, or taking a full-skull CBCT of the patient, and then performing three-dimensional modeling, separating the mandible, and simulating mandibular movement. The above methods are time-consuming and labor-intensive, and are difficult to apply clinically. At the same time, full-skull CBCT is expensive, and many clinics only have non-full-skull CBCT with a small field of view, which means that when photographing the teeth, it is impossible to capture both the left and right condyles.

[0006] For the clinical work of orthodontists, a more concise method is needed to complete the screening of jaw abnormalities. The present invention only requires the X-ray cephalometric film used in conventional orthodontic examination and analysis, and the upper and lower jaw three-dimensional tooth models in the CR and ICP positions to complete the jaw position analysis, which greatly simplifies the clinical operation. Summary of the invention

[0007] The purpose of the present invention is to complete jaw position analysis through X-ray lateral cephalograms used in conventional orthodontic examination and analysis, and three-dimensional tooth models of upper and lower jaws in CR and ICP positions, and use the average value method to set the bilateral condylar distance and analyze the condylar position, without actually measuring the patient's condylar distance, to check whether the jaw position of the orthodontic patient is abnormal. To achieve the above purpose, the present invention provides a jaw position analysis system and method based on X-ray lateral cephalograms.

[0008] In one embodiment, a jaw position analysis system based on X-ray cephalogram includes:

[0009] X-ray cephalogram tracing program module, used for tracing points of X-ray cephalogram;

[0010] Condylar center point calculation program module, used for calculating the position of the condylar center point;

[0011] A condylar center point offset program module is used to obtain the spatial positions of the left and right condylar center points by setting the condylar width and offsetting the condylar center point;

[0012] The crown segmentation and projection program module is used to segment the crown on the three-dimensional tooth model and project the outer edge of the crown onto the X-ray cephalogram;

[0013] A crown projection overlap program module is used to overlap the crown projection contour line with the crown image on the X-ray cephalogram;

[0014] A registration program module, used for registration between tooth models;

[0015] A condylar coordinate system generating program module is used to generate a condylar coordinate system;

[0016] A matrix calculation program module is used to calculate the matrix of the transformation matrix;

[0017] An output program module is used to output the offset values ​​of the left and right condylar center points;

[0018] The joint display program module is used to display the standard three-dimensional model of the condyle and glenoid fossa.

[0019] Furthermore, the X-ray cephalogram recording program module is specifically used for tracing points of the X-ray cephalogram to obtain the condylar vertex Co, the joint point Ar, the ear point Po, and the infraorbital point Or.

[0020] Furthermore, the condyle center point calculation program module is specifically used to calculate the position of the condyle center point. A perpendicular line V is made from the line connecting Co to Po and Or points, and a perpendicular line is made from Ar point to V to obtain the foot of the perpendicular Ax. The condyle center point is selected within a circle with Ax as the center and a radius of 1 mm.

[0021] Furthermore, the condylar center point offset program module is specifically used to obtain the spatial positions of the left and right condylar center points by setting the condylar width and offsetting the condylar center point.

[0022] Furthermore, any one of the condylar apex Co, the joint point Ar, and the ear point Po can be directly selected as the condylar center point without additional calculation, and the condylar center point can also be obtained by translating any one of these three points or other points.

[0023] Furthermore, the crown segmentation and projection program module is specifically used for segmenting the crown on the three-dimensional tooth model, and projecting the outer edge of the crown onto the X-ray cephalogram, simulating the radiation process of taking the X-ray film, and obtaining the projection contour line of the crown on the X-ray cephalogram.

[0024] Furthermore, the crown projection coincidence program module is specifically used to maintain the X-ray cephalogram still and perform operations such as translation, rotation, and scaling on the upper and lower jaw tooth models so that the projection contour line of the crown coincides with the crown image on the X-ray cephalogram.

[0025] Furthermore, the upper and lower jaw tooth models can be kept stationary, and the X-ray film can be translated, rotated, scaled, etc., so that the projection contour line of the crown coincides with the crown image on the X-ray cephalogram.

[0026] Furthermore, the condylar coordinate system generating program module is specifically used to use the line connecting the left and right condylar center points ab as the Y axis, the plane formed by the line connecting the infraorbital point Or and the left condylar center point a and the right condylar center point b as the horizontal plane, draw a perpendicular line to the Y axis through point a or point b in the horizontal plane to obtain the X axis, draw a perpendicular line perpendicular to the horizontal plane through point a or point b as the Z axis, generate the condylar coordinate system A with the left condylar center point a as the origin, and the three coordinate axes are X1, Y1, and Z1 respectively, and generate the condylar coordinate system B with the right condylar center point b as the origin, and the three coordinate axes are X2, Y2, and Z2 respectively.

[0027] Furthermore, the output program module is specifically used to output the offset values ​​of the left and right condyle center points in the condyle coordinate systems A and B, and to output the offset value of the midpoint of the line connecting the left and right condyle center points in the horizontal plane. When the output program module outputs the condyle center point offset value, the offset value of the left condyle center point in the condyle coordinate system A is an offset in the directions of the three coordinate axes X1, Y1, and Z1, and the offset value of the right condyle center point in the condyle coordinate system B is an offset in the directions of the three coordinate axes X2, Y2, and Z2.

[0028] Furthermore, the joint display program module displays a standard three-dimensional model of the condyle and glenoid fossa.

[0029] Furthermore, the matrix calculation program module is used to calculate the transformation matrix, and obtain the spatial positions of the center points of the left and right condyles after the transformation by calculating the transformation matrix of the mandibular tooth model in the CR and ICP positions.

[0030] In one embodiment, a jaw position analysis method based on an X-ray cephalogram includes:

[0031] Step 1: Obtain an ICP-positioned X-ray cephalogram and mark points to obtain the condylar vertex Co, joint point Ar, ear point Po, and infraorbital point Or. Draw a perpendicular line V from Co to the line connecting points Po and Or, and draw a perpendicular line from point Ar to V to obtain the foot of the perpendicular Ax. Select the condylar center point within a circle with a radius of 1 mm and Ax as the center.

[0032] Further, the ICP position X-ray cephalogram is an X-ray cephalogram taken when the patient's upper and lower teeth are in the ICP position, and the CR position X-ray cephalogram is an X-ray cephalogram taken when the patient's upper and lower teeth are in the CR position;

[0033] Step 2: Establish a reference coordinate system with the upper and lower jaw tooth models in the ICP position, place the X-ray lateral skull film at the mid-jaw suture of the maxillary tooth model, segment the crowns of the upper and lower jaw tooth models in the ICP position, and project the outer edges of the crowns onto the X-ray lateral skull film, simulate the radiation process of taking the X-ray film, and obtain the projection contour line of the crown on the X-ray lateral skull film;

[0034] Step 3: Keeping the X-ray cephalogram still, the upper and lower jaw tooth models in the ICP position are translated, rotated, scaled, etc., so that the projection contour of the crown coincides with the crown image on the X-ray cephalogram;

[0035] Step 4: In the reference coordinate system, translate Ax to the right by 1 / 2 of the condyle width to obtain the center point b of the right condyle, and translate Ax to the left by 1 / 2 of the condyle width to obtain the center point a of the left condyle;

[0036] Step 5, binding the left and right condylar center points a and b to the mandibular tooth model at the ICP position to obtain the first spatial position E of the left and right condylar center points and the first condylar axis ab;

[0037] Step 6, import the upper and lower jaw tooth models at the CR position, align and overlap the upper jaw tooth model at the CR position with the upper jaw tooth model at the ICP position, and move the mandibular tooth model at the CR position to follow the upper jaw tooth model. The mandibular tooth model at the CR position after movement is aligned with the mandibular tooth model at the ICP position, and the spatial transformation matrix G of the two is calculated through the matrix calculation program module;

[0038] Step 7, move the left and right condylar center points a and b from position E according to the spatial transformation matrix G to obtain points c and d respectively, and obtain the second spatial position F of the left and right condylar center points and the second condylar axis cd;

[0039] Step 8, take the line connecting ab as the Y axis, the plane formed by the line connecting the infraorbital point Or and points a and b as the horizontal plane, draw a perpendicular line to the Y axis through point a or point b on the horizontal plane to obtain the X axis, draw a perpendicular line perpendicular to the horizontal plane through point a or point b as the Z axis, take the center point a of the left condyle as the origin to generate the condylar coordinate system A, and the three coordinate axes are X1, Y1, and Z1 respectively, and take the center point b of the right condyle as the origin to generate the condylar coordinate system B, and the three coordinate axes are X2, Y2, and Z2 respectively;

[0040] Step nine, calculate the offset values ​​of the three plane projection points from point a to point c in the condylar coordinate system A, calculate the offset values ​​of the three plane projection points from point b to point d in the condylar coordinate system B, make a vertical plane to the straight line passing through the center points a and b of the left and right condyles, and calculate the offset values ​​of the projection points from point a to point b and from point c to point d on the vertical plane;

[0041] Step 10, the midpoint e of the line connecting the condylar center points a and b, and the midpoint f of the line connecting c and d, calculate the offset value of the projection point from e to f on the horizontal plane;

[0042] Step eleven, output the offset value of the center points of the left and right condyles, and output the offset value of the midpoint of the line connecting the center points of the left and right condyles.

[0043] Furthermore, the step 10 may also calculate the offset value of the projection points from e to f on the plane parallel to the horizontal plane.

[0044] Furthermore, the step one obtains the X-ray cephalogram at the CR position, the step six overlaps the crown projection contour lines of the upper and lower mandibular tooth models at the CR position with the crown image of the X-ray cephalogram, and the remaining steps replace the ICP position with the CR position, output the offset values ​​of the center points of the left and right condyles in the condylar coordinate systems A and B, and output the offset value of the midpoint of the line connecting the center points of the left and right condyles in the horizontal plane.

[0045] The invention discloses a jaw position analysis system based on X-ray cephalogram, comprising: an X-ray cephalogram recording program module, a condylar center point calculation program module, a condylar center point offset program module, a crown segmentation projection program module, a crown projection overlap program module, a registration program module, a condylar coordinate system generation program module, a matrix calculation program module, an output program module and a joint display program module. A jaw position analysis method based on X-ray cephalogram is to complete the jaw position analysis through the X-ray cephalogram used for conventional orthodontic examination and analysis, the upper and lower jaw three-dimensional tooth models of CR position and ICP position, and the average value method is used to set the bilateral condylar distance and analyze the jaw position, without actually measuring the condylar distance of the patient. It is used for clinical screening of jaw abnormality, finding patients with more serious jaw abnormality, assisting orthodontists in better program design, preventing possible temporomandibular joint problems, and making the correction results more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0047] Figure 1 This is a schematic diagram of cephalometric point mapping on a lateral X-ray skull film;

[0048] Figure 2 It is a schematic diagram of placing the X-ray cephalometric film at the mid-jaw suture of the maxillary dental model;

[0049] Figure 3 It is a schematic diagram showing the overlap between the projection outline of the tooth crown and the image of the tooth crown on the X-ray cephalogram;

[0050] Figure 4 Schematic diagram of operations such as translation, rotation, and scaling of the upper and lower mandibular dental models at the ICP position to keep the X-ray cephalogram still;

[0051] Figure 5 It is a schematic diagram of the combination of the X-ray cephalogram and the registered three-dimensional dental models of the upper and lower jaws;

[0052] Figure 6 This is the offset diagram of the midpoint e of ab and the midpoint f of cd in the horizontal plane;

[0053] Figure 7 A flowchart of a jaw position analysis method based on X-ray cephalogram; 10-jaw suture, 20-contour line, 30-translation, rotation, scaling and other operations, 40-offset value of the projection point from e to f on the horizontal plane DETAILED DESCRIPTION

[0054] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but are not to be construed as limiting the present invention. All other embodiments obtained by ordinary technicians in the field without creative work based on the embodiments of the present invention are within the scope of protection of the present invention.

[0055] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0056] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0057] Exemplarily, a jaw position analysis system based on X-ray cephalogram includes:

[0058] X-ray cephalogram tracing program module, used for tracing points of X-ray cephalogram;

[0059] Condylar center point calculation program module, used for calculating the position of the condylar center point;

[0060] A condylar center point offset program module is used to obtain the spatial positions of the left and right condylar center points by setting the condylar width and offsetting the condylar center point;

[0061] The crown segmentation and projection program module is used to segment the crown on the three-dimensional tooth model and project the outer edge of the crown onto the X-ray cephalogram;

[0062] A crown projection overlap program module is used to overlap the crown projection contour line with the crown image on the X-ray cephalogram;

[0063] A registration program module, used for registration between tooth models;

[0064] A condylar coordinate system generating program module is used to generate a condylar coordinate system;

[0065] A matrix calculation program module is used to calculate the matrix of the transformation matrix;

[0066] An output program module is used to output the offset values ​​of the left and right condylar center points;

[0067] The joint display program module is used to display the standard three-dimensional model of the condyle and glenoid fossa.

[0068] Exemplarily, a jaw position analysis method based on X-ray cephalogram includes:

[0069] See also Figure 1 and Figure 7 Step 1: Obtain an ICP-position X-ray lateral skull film and draw points to obtain the condylar vertex Co, joint point Ar, ear point Po, and infraorbital point Or. Draw a perpendicular line V from Co to the line connecting points Po and Or, and draw a perpendicular line from point Ar to V to obtain the foot of the perpendicular Ax. Select the condylar center point within a circle with a radius of 1 mm and Ax as the center.

[0070] Furthermore, in the step 1, cephalometric measurement is an analysis that every orthodontic patient needs to do, and the jaw position analysis can be completed without any extra work. Since the condylar vertex Co and joint point Ar of the cephalometric measurement are points on the condylar surface, the actual condylar center point is inside the condyle. Through the calculation in step 1, the obtained condylar center point is made as close as possible to the actual condylar center point.

[0071] Furthermore, in step 1, any one of the condylar vertex Co, the joint point Ar, and the ear point Po can be directly selected as the condylar center point without additional calculation, and any one of these three points or other points can be used for translation to obtain the condylar center point.

[0072] Furthermore, after the condyle center point is offset to the left and right to obtain the left condyle center point a and the right condyle center point b, the three-dimensional spatial positions of point a and point b can be adjusted to facilitate the doctor to adjust them to be consistent with the condyle center point position on the CT image.

[0073] See also Figure 2, Step 2, establish a reference coordinate system with the upper and lower jaw tooth models in the ICP position, and place the X-ray cephalogram at the mid-jaw suture of the maxillary tooth model 10.

[0074] Furthermore, the lateral X-ray cephalogram may be placed at the mid-jaw suture of the maxillary dental model before obtaining the ICP position of the lateral X-ray cephalogram.

[0075] See also Figure 3 , segment the crowns of the upper and lower jaw tooth models in the ICP position, and project the outer edges of the crowns onto the X-ray cephalogram, simulate the radiation process of taking X-rays, and obtain the projection contour lines of the crowns on the X-ray cephalogram.

[0076] Furthermore, in the step 2, because the X-ray cephalogram is taken, the crowns on the upper and lower jaw dental models are projected onto a plane, and the center plane where the mid-jaw suture is located is more accurate.

[0077] See also Figure 4 Step 3: Keeping the X-ray cephalogram still, the upper and lower jaw tooth models in the ICP position are translated, rotated, scaled, etc. 30, so that the projection contour line 20 of the crown coincides with the crown image on the X-ray cephalogram;

[0078] Furthermore, in the step three, the X-ray shooting process is simulated to make the projection contour line of the crown coincide with the crown image of the X-ray lateral film as much as possible.

[0079] Furthermore, the upper and lower jaw tooth models can be kept stationary, and the X-ray film can be translated, rotated, scaled, etc., so that the projection contour line of the crown coincides with the crown image on the X-ray cephalogram.

[0080] See also Figure 5 , step 4, in the reference coordinate system, translate Ax to the right by 1 / 2 of the set condyle width to obtain the right condyle center point b, and translate Ax to the left by 1 / 2 of the set condyle width to obtain the left condyle center point a;

[0081] Furthermore, in step 4, the operation of directly converting the condylar center point from two dimensions to three dimensions greatly simplifies the jaw analysis process, does not require a face bow or a jaw frame, and is faster and more convenient. At the same time, when performing jaw analysis on a conventional jaw frame, the condylar-ball distance on the jaw frame is fixed, and the fixed left and right condylar widths are used for analysis, without actually measuring the condylar distance of the patient. Therefore, the fastest method of the present invention is also to use the average method to set the left and right condylar distances and directly calculate the results. The present invention can preset different condylar widths for children and adult patients according to age. At the same time, tools such as measuring instruments and face bows can also be used to actually measure the condylar width values ​​and then input them for calculation. Although the results of jaw analysis using the average method may not be so accurate, clinicians can use it to screen for jaw abnormalities, find patients with more serious jaw abnormalities, assist orthodontists in better program design, prevent possible temporomandibular joint problems, and make the correction results more stable.

[0082] See also Figure 5 , step 5, binding the left and right condylar center points a, b with the mandibular tooth model at the ICP position to obtain the first spatial position E of the left and right condylar center points and the first condylar axis ab;

[0083] Step 6, import the upper and lower jaw tooth models at the CR position, align and overlap the upper jaw tooth model at the CR position with the upper jaw tooth model at the ICP position, and move the mandibular tooth model at the CR position to follow the upper jaw tooth model. The mandibular tooth model at the CR position after movement is aligned with the mandibular tooth model at the ICP position, and the spatial transformation matrix G of the two is calculated through the matrix calculation program module;

[0084] Furthermore, if there is only one maxillary tooth model and one mandibular tooth model, a bite record at the CR position and a bite record at the ICP position, the upper and lower mandibular tooth models are aligned with the bite record at the CR position to obtain the upper and lower mandibular tooth models at the CR position, and the bite record at the ICP position is aligned to obtain the upper and lower mandibular tooth models at the ICP position.

[0085] Step 7, move the left and right condylar center points a and b from position E according to the spatial transformation matrix G to obtain points c and d respectively, and obtain the second spatial position F of the left and right condylar center points and the second condylar axis cd;

[0086] Step 8, take the line connecting ab as the Y axis, the plane formed by the line connecting the infraorbital point Or and points a and b as the horizontal plane, draw a perpendicular line to the Y axis through point a or point b on the horizontal plane to obtain the X axis, draw a perpendicular line perpendicular to the horizontal plane through point a or point b as the Z axis, take the center point a of the left condyle as the origin to generate the condylar coordinate system A, and the three coordinate axes are X1, Y1, and Z1 respectively, and take the center point b of the right condyle as the origin to generate the condylar coordinate system B, and the three coordinate axes are X2, Y2, and Z2 respectively;

[0087] Furthermore, in step eight, the establishment of the condylar coordinate system allows the doctor to intuitively see the direction of the offset in a three-dimensional scene, visualize the jaw offset that was difficult to understand in the past, and make it easier to formulate a correction plan.

[0088] Step nine, calculate the offset values ​​of the three plane projection points from point a to point c in the condylar coordinate system A, calculate the offset values ​​of the three plane projection points from point b to point d in the condylar coordinate system B, make a vertical plane to the straight line passing through the center points a and b of the left and right condyles, and calculate the offset values ​​of the projection points from point a to point b and from point c to point d on the vertical plane;

[0089] See also Figure 6 , step 10, the midpoint e of the line connecting the condylar center points a and b, and the midpoint f of the line connecting c and d, calculate the offset value of the projection point from e to f on the horizontal plane;

[0090] Furthermore, the projection point offset value 40 from e to f on a plane parallel to the horizontal plane may also be calculated.

[0091] Step eleven, output the offset value of the center points of the left and right condyles, and output the offset value of the midpoint of the line connecting the center points of the left and right condyles.

[0092] Furthermore, another step of the jaw position analysis method based on X-ray cephalogram is as follows: step one obtains the CR position to take a cephalogram, step six overlaps the crown projection contour lines of the upper and lower jaw tooth models at the CR position with the crown image of the X-ray cephalogram, and the remaining steps replace the ICP position with the CR position, and output the offset values ​​of the center points of the left and right condyles in the condylar coordinate systems A and B and the offset value of the midpoint of the line connecting the center points of the left and right condyles in the horizontal plane.

[0093] Furthermore, the output program module outputs the offset value of the left and right condylar center points to determine whether the CR position is coordinated with the ICP position. Ideally: CR = ICP, acceptable range: anteroposterior ≤ 1mm, vertical ≤ 1mm, lateral ≤ 0.5mm, the greater the reading difference, the higher the probability of TMJ symptoms. Therefore, the pursuit of consistency between CR and ICP, or the coordination of the centric relationship position with the cusp interdigitation position, is the first goal pursued by the present invention.

[0094] The invention discloses a jaw position analysis system based on X-ray cephalogram, comprising: an X-ray cephalogram recording program module, a condylar center point calculation program module, a condylar center point offset program module, a crown segmentation projection program module, a crown projection overlap program module, a registration program module, a condylar coordinate system generation program module, a matrix calculation program module, an output program module and a joint display program module. A jaw position analysis method based on X-ray cephalogram is to complete jaw position analysis through X-ray cephalogram used for conventional orthodontic examination and analysis, CR, ICP upper and lower jaw three-dimensional tooth models, and adopt the average method to set the bilateral condylar distance and analyze the condylar position, without actually measuring the patient's condylar distance. It is used for clinical screening of jaw abnormality, finding patients with more serious jaw abnormality, assisting orthodontists in better program design, preventing possible temporomandibular joint problems, and making the correction results more stable.

[0095] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0096] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A jaw position analysis system based on X-ray cephalogram, characterized in that: Include: X-ray cephalogram tracing program module, used for tracing points of X-ray cephalogram; Condylar center point calculation program module, used for calculating the position of the condylar center point; A condylar center point offset program module is used to obtain the spatial positions of the left and right condylar center points by setting the condylar width and offsetting the condylar center point; The crown segmentation and projection program module is used to segment the crown on the three-dimensional tooth model and project the outer edge of the crown onto the X-ray cephalogram; A crown projection overlap program module is used to overlap the crown projection contour line with the crown image on the X-ray cephalogram; A registration program module, used for registration between tooth models; A condylar coordinate system generating program module is used to generate a condylar coordinate system; A matrix calculation program module is used to calculate the matrix of the transformation matrix; An output program module is used to output the offset values ​​of the left and right condylar center points; The joint display program module is used to display the standard three-dimensional model of the condyle and glenoid fossa.

2. The jaw position analysis system based on X-ray cephalogram according to claim 1, characterized in that: The X-ray cephalogram tracing program module is specifically used for tracing points of the X-ray cephalogram to obtain the condylar vertex Co, the joint point Ar, the ear point Po, and the infraorbital point Or.

3. The jaw position analysis system based on X-ray cephalogram according to claim 1, characterized in that: The condyle center point calculation program module is specifically used to calculate the position of the condyle center point. A perpendicular line V is made from the line connecting Co to Po and Or points, and a perpendicular line is made from Ar point to V to obtain the foot of the perpendicular Ax. The condyle center point is selected within a circle with Ax as the center and a radius of 1 mm. The condyle center point offset program module is specifically used to obtain the spatial position of the left and right condyle center points by setting the condyle width and offsetting the condyle center point.

4. The jaw position analysis system based on X-ray cephalogram according to claim 1, characterized in that: The crown segmentation and projection program module is specifically used for segmenting the crown on the three-dimensional tooth model, and projecting the outer edge of the crown onto the X-ray cephalogram, simulating the radiation process of taking the X-ray film, and obtaining the projection contour line of the crown on the X-ray cephalogram.

5. The jaw position analysis system based on X-ray cephalogram according to claim 1, characterized in that: The crown projection coincidence program module is specifically used to keep the X-ray cephalogram still and perform operations such as translation, rotation, and scaling on the upper and lower jaw tooth models so that the projection contour line of the crown coincides with the crown image on the X-ray cephalogram.

6. The jaw position analysis system based on X-ray cephalogram according to claim 1, characterized in that: The condylar coordinate system generating program module is specifically used to use the line connecting the left and right condylar center points ab as the Y axis, the plane formed by the line connecting the infraorbital point Or and the left condylar center point a and the right condylar center point b as the horizontal plane, draw a perpendicular line to the Y axis through point a or point b in the horizontal plane to obtain the X axis, draw a perpendicular line perpendicular to the horizontal plane through point a or point b as the Z axis, generate the condylar coordinate system A with the left condylar center point a as the origin, and the three coordinate axes are X1, Y1, and Z1 respectively, and generate the condylar coordinate system B with the right condylar center point b as the origin, and the three coordinate axes are X2, Y2, and Z2 respectively.

7. The jaw position analysis system based on X-ray cephalogram according to claim 1, characterized in that: The output program module is specifically used to output the offset values ​​of the center points of the left and right condyles in the condylar coordinate systems A and B, and to output the offset value of the midpoint of the line connecting the center points of the left and right condyles in the horizontal plane. When the output program module outputs the offset values ​​of the condylar center points, the offset value of the center point of the left condyle in the condylar coordinate system A is the offset in the directions of the three coordinate axes of X1, Y1, and Z1, and the offset value of the center point of the right condyle in the condylar coordinate system B is the offset in the directions of the three coordinate axes of X2, Y2, and Z2. The joint display program module displays the standard three-dimensional model of the condyle and articular fossa.

8. A jaw position analysis method based on X-ray cephalographic film, characterized in that: The method for the jaw position analysis system based on X-ray cephalogram according to any one of claims 1 to 7 comprises: Step 1: Obtain an ICP-positioned X-ray cephalogram and mark points to obtain the condylar vertex Co, joint point Ar, ear point Po, and infraorbital point Or. Draw a perpendicular line V from Co to the line connecting points Po and Or, and draw a perpendicular line from point Ar to V to obtain the foot of the perpendicular Ax. Select the condylar center point within a circle with a radius of 1 mm and Ax as the center. Step 2: Establish a reference coordinate system with the upper and lower jaw tooth models in the ICP position, place the X-ray lateral skull film at the mid-jaw suture of the maxillary tooth model, segment the crowns of the upper and lower jaw tooth models in the ICP position, and project the outer edges of the crowns onto the X-ray lateral skull film, simulate the radiation process of taking the X-ray film, and obtain the projection contour line of the crown on the X-ray lateral skull film; Step 3: Keeping the X-ray cephalogram still, the upper and lower jaw tooth models in the ICP position are translated, rotated, scaled, etc., so that the projection contour of the crown coincides with the crown image on the X-ray cephalogram; Step 4: In the reference coordinate system, translate Ax to the right by 1 / 2 of the condyle width to obtain the center point b of the right condyle, and translate Ax to the left by 1 / 2 of the condyle width to obtain the center point a of the left condyle; Step 5, binding the left and right condylar center points a and b to the mandibular tooth model at the ICP position to obtain the first spatial position E of the left and right condylar center points and the first condylar axis ab; Step 6, import the upper and lower jaw tooth models at the CR position, align and overlap the upper jaw tooth model at the CR position with the upper jaw tooth model at the ICP position, and move the mandibular tooth model at the CR position to follow the upper jaw tooth model. The mandibular tooth model at the CR position after movement is aligned with the mandibular tooth model at the ICP position, and the spatial transformation matrix G of the two is calculated through the matrix calculation program module; Step 7, move the left and right condylar center points a and b from position E according to the spatial transformation matrix G to obtain points c and d respectively, and obtain the second spatial position F of the left and right condylar center points and the second condylar axis connecting line cd; Step 8, take the line connecting ab as the Y axis, the plane formed by the line connecting the infraorbital point Or and points a and b as the horizontal plane, draw a perpendicular line to the Y axis through point a or point b on the horizontal plane to obtain the X axis, draw a perpendicular line perpendicular to the horizontal plane through point a or point b as the Z axis, take the center point a of the left condyle as the origin to generate the condylar coordinate system A, and the three coordinate axes are X1, Y1, and Z1 respectively, and take the center point b of the right condyle as the origin to generate the condylar coordinate system B, and the three coordinate axes are X2, Y2, and Z2 respectively; Step nine, calculate the offset values ​​of the three plane projection points from point a to point c in the condylar coordinate system A, calculate the offset values ​​of the three plane projection points from point b to point d in the condylar coordinate system B, make a vertical plane to the straight line passing through the center points a and b of the left and right condyles, and calculate the offset values ​​of the projection points from point a to point b and from point c to point d on the vertical plane; Step 10, the midpoint e of the line connecting the condylar center points a and b, and the midpoint f of the line connecting c and d, calculate the offset value of the projection point from e to f on the horizontal plane; Step 11: Output the offset value of the left and right condyle center points, and output the left and right condyle center points. The offset value of the midpoint of the line connecting the points.

9. The jaw position analysis method based on X-ray cephalogram according to claim 8, characterized in that: The step 1 obtains the X-ray lateral skull film marking points at the CR position, and the step 6 overlaps the crown projection contour lines of the upper and lower jaw tooth models at the CR position with the crown image of the X-ray lateral skull film. The remaining steps replace the ICP position with the CR position, output the offset values ​​of the center points of the left and right condyles in the condylar coordinate systems A and B, and output the offset value of the midpoint of the line connecting the center points of the left and right condyles in the horizontal plane.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to claim 8 or 9 is implemented.

Images