Orthodontic tooth movement monitoring method and system based on wax bite record

Abstract

The application provides an orthodontic tooth movement monitoring method and system based on wax occlusion records, which comprises the following steps: obtaining an intraoral scanning model and a cone beam CT tooth model at time T0, superimposing the two models to obtain a complete model of each tooth containing a tooth crown and a tooth root; obtaining a wax occlusion record at time T N , optically scanning the wax occlusion record to obtain a three-dimensional digital model of the occlusion record and uploading the three-dimensional digital model; matching the occlusion pits of the digital model of the occlusion record with the occlusal surfaces of the complete model of each tooth to restore a tooth position model at time T N ; superimposing the tooth position models at times T0 and T N , and establishing a local three-dimensional coordinate system for each tooth; calculating three-dimensional movement data of the teeth; and a doctor remotely monitors the tooth movement of a patient with high accuracy by obtaining accurate three-dimensional data of the tooth position changes, provides reliable data for subsequent correction, and guides the next treatment of the patient.

Description

Technical Field

[0001] This invention relates to a method and system for monitoring orthodontic tooth movement based on wax occlusion recording, belonging to the field of oral monitoring technology. Background Technology

[0002] Dentofacial deformities are a common and prevalent oral disease, referring to various deformities of the teeth, jawbone, and craniofacial region caused by genetic and environmental factors. Orthodontic treatment utilizes the forces generated by braces to act directly or indirectly on the teeth, inducing tooth movement or jawbone growth remodeling, thereby aligning the teeth, restoring normal occlusal function, improving facial appearance, and correcting dentofacial deformities.

[0003] Currently, the standard procedure for orthodontic treatment involves orthodontists collecting relevant medical records about the patient's dentofacial deformity during the initial consultation, such as cone-beam CT scans, dental impressions, and intraoral and extraoral digital photographs. After diagnostic analysis, a treatment plan is developed, and orthodontic treatment begins only after obtaining informed consent from the patient through thorough communication. Patients need to attend follow-up appointments monthly during treatment. The orthodontist assesses the patient's intraoral condition and determines subsequent treatment procedures. The entire treatment cycle typically takes two to two and a half years. Under this model, the orthodontist can only observe changes in tooth position during the patient's follow-up appointments.

[0004] In recent years, although the rapid development of clear aligners has reduced the frequency of patient follow-up visits to once every two months or even longer, the biomechanical principles underlying their control of orthodontic tooth movement are still not fully understood. Deviating from the original treatment plan and requiring intervention by the dentist still occurs frequently. Furthermore, because patients are unaware of their tooth movement, they cannot promptly return for follow-up appointments. By the time the dentist discovers this, it is often too late to simply reverse the treatment, necessitating a restart of the entire process. This effectively increases the frequency of patient visits and prolongs the treatment cycle. Therefore, a method for effectively monitoring orthodontic tooth movement is of paramount importance to both orthodontists and patients.

[0005] Existing methods for monitoring tooth movement involve patients taking intraoral photographs at home and uploading them to a dentist. For example, Chinese patent application CN2020107878101 discloses an image processing-based method for monitoring tooth position. However, because it uses two-dimensional photographs, there is significant error when using them to monitor three-dimensional tooth movement. Furthermore, the results are highly dependent on the patient's operation, leading to instability and poor reliability. On the other hand, although the accuracy of optical scanners has reached clinical requirements due to the rapid development of optical scanning technology, intraoral optical scanners can record tooth position in three dimensions, facilitating precise tooth movement analysis by dentists. However, these scanners are expensive and require professional medical personnel to operate, meaning patients still need to visit a medical institution for scanning, thus not substantially reducing the frequency of visits. Therefore, this invention aims to combine the advantages of optical scanning to provide a new method for remote tooth movement monitoring. Summary of the Invention

[0006] The purpose of this invention is to provide a method and system for monitoring orthodontic tooth movement based on wax occlusion records, which solves the problem that the accuracy of remote monitoring during orthodontic procedures needs to be improved in the existing technology.

[0007] The technical solution of this invention is:

[0008] A method for monitoring orthodontic tooth movement based on wax occlusion recording includes the following steps:

[0009] S1. Obtain the intraoral scan model and cone-beam CT tooth model at the time T0 before orthodontic treatment, and superimpose them to obtain a complete dentition model including the crown and root.

[0010] S2, Obtain the orthodontic midpoint time T N The wax bite record was optically scanned to obtain a three-dimensional digital model of the bite record;

[0011] S3. Match the occlusal record 3D digital model obtained in step S2 with the complete dentition model to reconstruct time T. N A model of tooth position;

[0012] S4, Overlapping times T0 and T N The tooth position model was created, and a local three-dimensional coordinate system was established for each tooth;

[0013] S5. Using the overlap model and local three-dimensional coordinate system obtained in step S4, perform single tooth overlap analysis and calculate the three-dimensional movement data of the tooth.

[0014] S6. Repeat step S5 until the three-dimensional movement data of all teeth in the dentition are obtained through analysis.

[0015] Furthermore, it also includes step S7, in which T data are continuously collected at different times during the patient's orthodontic treatment via steps S1 to S5. N The wax bite record was recorded and analyzed to obtain the position information and three-dimensional movement record of all the patient's teeth throughout the entire orthodontic cycle.

[0016] Furthermore, in step S3, the 3D digital model of the occlusion record obtained in step S2 is matched with the complete dental arch model to reconstruct time T. N The tooth position model, specifically,

[0017] S31. Select three feature points on the three-dimensional digital model of occlusion record and the complete dental arch model respectively to calculate the transformation matrix, transform the two models into the same coordinate system, and then perform fine registration of the two models based on the ICP algorithm.

[0018] S32. Segment the teeth on the three-dimensional digital model of the occlusion record and restore the morphology of the interdental adhesion area;

[0019] S33. Calculate the average curvature of the wax occlusion record model, extract the points with curvature values ​​within a given range as the boundaries of the occlusal pits of each tooth, and then obtain the boundaries of the occlusal pits of each tooth based on morphological methods and skeleton extraction methods.

[0020] S34. By registering each segmented tooth and its corresponding occlusal pit, the current position of the patient's teeth can be restored, and the time T can be obtained. N A model of tooth position.

[0021] Furthermore, in step S4, a local three-dimensional coordinate system is established for each tooth, specifically as follows:

[0022] S41. Based on the morphological characteristics of a single tooth crown, extract the feature regions corresponding to the incisal ridge and cusp ridge on the tooth crown according to the given average curvature threshold.

[0023] S42. Then, the feature region is fitted using the eigenvalue decomposition method, and the transformation is adjusted to obtain the local reference plane F0 on a single tooth crown.

[0024] S43. Interactively select the width direction of all crowns and calculate their axial bounding box. Select the center of the quadrilateral whose crown bounding box coincides with the local reference plane F0 as the origin of the local coordinate system, the width direction as the local coordinate principal axis u, and the axis that coincides with the normal of the local coordinate plane as the w axis. The v axis can be determined according to the right-hand rule.

[0025] Furthermore, in step S2, time T is obtained. NThe wax occlusion record is obtained by heating a wax sheet into a horseshoe shape, placing it on the lower dental arch, biting down, and then slowly removing the wax sheet after it cools and hardens. After confirming that the tooth imprint is intact and the wax sheet is not deformed, the wax occlusion record is obtained by rinsing with water and drying it.

[0026] Furthermore, in step S5, the three-dimensional tooth movement data includes tooth movement distance and tooth movement angle. The tooth movement distance includes elongation / intrusion distance, labial / lingual movement distance, and mesial / distal movement distance; the tooth movement angle includes torsion angle, mesial / distal tilt angle, and labial / lingual tilt angle.

[0027] A system for implementing the orthodontic tooth movement monitoring method based on wax occlusion recording as described above includes a three-dimensional model acquisition terminal and a monitoring terminal.

[0028] 3D model acquisition terminal: Obtaining the time T before orthodontic treatment from occlusal wax films. N The wax bite record was obtained by a 3D scanner at time T. N The wax bite record is optically scanned to obtain a three-dimensional digital model of the bite record, which is then sent to the monitoring terminal via a communication module.

[0029] The monitoring terminal includes a complete model generation module and a location monitoring module.

[0030] Complete model generation module: An intraoral scanning model of the dentition of the patient at time T0 during orthodontic treatment is obtained using an intraoral scanner, and a cone-beam CT tooth model is obtained using an oral cone-beam CT device; the obtained intraoral scanning model and cone-beam CT tooth model are superimposed to obtain a complete dentition model including the crowns and roots;

[0031] Position monitoring module: Matches the obtained occlusal record 3D digital model with the complete dentition model to reconstruct the time T. N Tooth position model; complete tooth row model obtained by overlapping time T0 and time T N The tooth position model is obtained, and a local three-dimensional coordinate system is established for each tooth; the position movement data of the teeth are calculated by using the obtained overlapping tooth position model and local three-dimensional coordinate system.

[0032] Furthermore, in the 3D model acquisition terminal, a handheld 3D scanner is used to measure time T. N Optical scanning was performed on the wax occlusion record to obtain a three-dimensional digital model of the dentition.

[0033] The beneficial effects of this invention are:

[0034] This orthodontic tooth movement monitoring method and system based on wax occlusion recording obtains the patient's wax occlusion record through occlusion wax sheets, reconstructs the patient's intraoral dentition, and then obtains accurate three-dimensional data on changes in tooth position. It achieves highly accurate remote monitoring of the patient's tooth movement, provides reliable data for subsequent orthodontic treatment, and facilitates doctors in guiding the patient's next treatment steps.

[0035] This application proposes a solution that uses a handheld 3D scanner to obtain occlusal data. Compared to existing technologies, handheld 3D scanners are cheaper than intraoral optical scanners. More importantly, scanning wax occlusal records with a handheld 3D scanner is significantly easier than traditional intraoral dentition scanning. Patients can easily complete the scan and upload the data without going to the hospital, reducing the number of times they need to visit the hospital and enabling remote monitoring. Attached Figure Description

[0036] Figure 1 This is a flowchart illustrating the orthodontic tooth movement monitoring method based on wax occlusion recording according to an embodiment of the present invention.

[0037] Figure 2 This is an illustrative diagram illustrating the acquisition of a complete dentition model including crowns and roots at time T0 before orthodontic treatment in the embodiment.

[0038] Figure 3 The time T during orthodontic treatment is obtained in the example. N A diagram illustrating the wax bite record;

[0039] Figure 4 The time T obtained in the embodiment N A schematic diagram illustrating the tooth position model;

[0040] Figure 5 This is an illustrative diagram illustrating the acquisition of the overlapping model in the embodiment;

[0041] Figure 6 This is a schematic diagram illustrating the single-tooth overlap analysis in the embodiment;

[0042] Figure 7 This is an illustrative diagram illustrating the orthodontic tooth movement monitoring system based on wax occlusion recording according to an embodiment of the present invention. Detailed Implementation

[0043] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0044] Example

[0045] A method for monitoring orthodontic tooth movement based on wax occlusion recording, such as Figure 1 This includes the following steps:

[0046] S1. Obtain the intraoral scan model and cone-beam CT tooth model at the pre-orthodontic time T0, and overlay them to obtain a complete dentition model including the crowns and roots, such as... Figure 2 In step S1, the cone-beam computed tomography (CBCT) tooth model is a tooth model that uses cone-beam computed tomography (CBCT) scanning.

[0047] S2, Obtain the orthodontic midpoint time T N Waxed bite records, such as Figure 3 Optical scanning was performed on the wax bite record to obtain a three-dimensional digital model of the bite record;

[0048] In step S2, time T is obtained. N The wax occlusion record is obtained by heating a wax sheet into a horseshoe shape, placing it on the lower dental arch, biting down, and then slowly removing the wax sheet after it cools and hardens. After confirming that the tooth imprint is intact and the wax sheet is not deformed, the wax occlusion record is obtained by rinsing with water and drying it.

[0049] S3. Match the occlusal record 3D digital model obtained in step S2 with the complete dentition model to reconstruct time T. N Tooth position model, such as Figure 4 ;

[0050] S31. Select three feature points on the three-dimensional digital model of occlusion record and the three-dimensional digital model of dental arch respectively to calculate the transformation matrix, transform the two models into the same coordinate system, and then perform fine registration of the two models based on the ICP algorithm; where ICP algorithm: Iterative Closest Point algorithm, i.e., iterative closest point algorithm;

[0051] In step S31, transforming the two models into the same coordinate system provides a better initial position for the fine registration of the complete dental arch model and the occlusal record 3D digital model, enabling the fine registration to converge faster and more accurately, and avoiding the iteration process from getting trapped in erroneous local extrema. Then, based on the above initial position, the ICP algorithm is used to perform fine registration of the two models. Fine registration further minimizes the spatial position difference between the two models after transforming them into the same coordinate system, thereby improving the overlap accuracy of the models.

[0052] S32. Segment the teeth on the three-dimensional digital model of the occlusion record and restore the morphology of the interdental adhesion area;

[0053] S33. Calculate the average curvature of the wax occlusion record model, extract the points with curvature values ​​within a given range as the boundaries of the occlusal pits of each tooth, and then obtain the boundaries of the occlusal pits of each tooth based on morphological methods and skeleton extraction methods.

[0054] S34. By registering each segmented tooth and its corresponding occlusal pit, the current position of the patient's teeth can be restored, and the time T can be obtained. N A model of tooth position.

[0055] S4. The complete dental arch model obtained at overlapping time T0 and time T N From the tooth position model, obtain the overlapping model, such as Figure 5 And establish a local three-dimensional coordinate system for each tooth;

[0056] S41. Based on the morphological characteristics of a single tooth crown, extract the feature regions corresponding to the incisal ridge and cusp ridge on the tooth crown according to the given average curvature threshold.

[0057] S42. Then, the feature region is fitted using the eigenvalue decomposition method, and the transformation is adjusted to obtain the local reference plane F0 on a single tooth crown.

[0058] S43. Interactively select the width direction of all crowns and calculate their axial bounding box. Select the center of the quadrilateral whose crown bounding box coincides with the local reference plane F0 as the origin of the local coordinate system, the width direction as the local coordinate principal axis u, and the axis that coincides with the normal of the local coordinate plane as the w axis. The v axis can be determined according to the right-hand rule.

[0059] S5. Using the overlap model and local three-dimensional coordinate system obtained in step S4, perform overlap analysis on a single tooth, such as... Figure 6 The three-dimensional movement data of the teeth is calculated. In step S5, the tooth position movement data includes the tooth movement distance and the tooth movement angle. The tooth movement distance includes elongation / intrusion distance, labial / lingual movement distance, and mesial / distal movement distance, and the tooth movement angle includes torsion angle, mesial / distal tilt angle, and labial / lingual tilt angle.

[0060] S6. Repeat step S5 until the three-dimensional movement data of all teeth in the dentition are obtained through analysis.

[0061] It also includes step S7, in which T data are continuously collected at different times during the orthodontic treatment of the patient through steps S1 to S5. N The wax bite record was recorded and analyzed to obtain the position information and three-dimensional movement record of all the patient's teeth throughout the entire orthodontic cycle.

[0062] This orthodontic tooth movement monitoring method and system based on wax occlusion recording obtains the patient's wax occlusion record through occlusion wax sheets, reconstructs the patient's intraoral dentition, and then obtains accurate three-dimensional data on changes in tooth position. It achieves highly accurate remote monitoring of the patient's tooth movement, provides reliable data for subsequent orthodontic treatment, and facilitates doctors in guiding the patient's next treatment steps.

[0063] This orthodontic tooth movement monitoring method based on wax occlusion recording also includes step S7, which involves continuously collecting T data from the patient at different times during the orthodontic process through steps S1 to S5. N The wax bite record was recorded and analyzed to obtain the position information and three-dimensional movement record of all the patient's teeth throughout the entire orthodontic cycle.

[0064] The embodiments also provide a system for implementing the orthodontic tooth movement monitoring method based on wax occlusion recording as described in any of the above embodiments, such as... Figure 7 This includes 3D model acquisition terminals and monitoring terminals.

[0065] 3D model acquisition terminal: Obtaining the time T before orthodontic treatment from occlusal wax films. N The wax bite record was obtained by a 3D scanner at time T. N The wax bite record is optically scanned to obtain a three-dimensional digital model of the dental arch, which is then sent to the monitoring terminal via a communication module.

[0066] The monitoring terminal includes a complete model generation module and a location monitoring module.

[0067] Complete model generation module: An intraoral scanning model of the dentition of the patient at time T0 during orthodontic treatment is obtained using an intraoral scanner, and a cone-beam CT tooth model is obtained using an oral cone-beam CT device; the obtained intraoral scanning model and cone-beam CT tooth model are superimposed to obtain a complete dentition model including the crowns and roots;

[0068] Position monitoring module: Matches the obtained occlusal record 3D digital model with the complete dentition model to reconstruct the time T. N Tooth position model; complete tooth row model obtained by overlapping time T0 and time T N The tooth position model is obtained, and a local three-dimensional coordinate system is established for each tooth; the position movement data of the teeth are calculated by using the obtained overlapping tooth position model and local three-dimensional coordinate system.

[0069] In the 3D model acquisition terminal, a handheld 3D scanner (Shinsen EinScan Pro 2X) is used to measure time T. N Optical scanning was performed on the wax occlusion record to obtain a three-dimensional digital model of the dentition.

[0070] In this orthodontic tooth movement monitoring system based on wax occlusion recording, the 3D model acquisition terminal can be operated by the patient to obtain a 3D digital model of the dentition. The patient then remotely sends this 3D digital model to the monitoring terminal. Upon receiving the 3D digital model, the monitoring terminal compares it with a complete dentition model to obtain tooth position and movement data for the doctor's review. This system allows patients to obtain a 3D digital model of their dentition through the 3D model acquisition terminal and then remotely send it to the monitoring terminal, enabling home-based follow-up appointments.

[0071] This orthodontic tooth movement monitoring method and system based on wax occlusion recording can reduce the frequency of patient visits, while allowing physicians to effectively monitor and observe the three-dimensional tooth movement of patients, bringing a more convenient and efficient treatment experience to both physicians and patients.

[0072] The above embodiments are merely illustrative of the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any improvements and modifications made to the technical solution based on the technical concept proposed in this invention are within the scope of protection of this invention.

Claims

1. A method for monitoring orthodontic tooth movement based on wax occlusion recording, characterized in that: Includes the following steps, S1. Obtain the intraoral scan model and cone-beam CT tooth model at the time T0 before orthodontic treatment, and superimpose them to obtain a complete dentition model including the crown and root. S2, Obtain the orthodontic midpoint time T N The wax bite record was optically scanned to obtain a three-dimensional digital model of the bite record; S3. Match the occlusal record 3D digital model obtained in step S2 with the complete dentition model to reconstruct time T. N A tooth position model; specifically, S31. Select three feature points on the three-dimensional digital model of occlusion record and the complete dental arch model respectively to calculate the transformation matrix, transform the two models into the same coordinate system, and then perform fine registration of the two models based on the ICP algorithm. S32. Segment the teeth on the three-dimensional digital model of the occlusion record and restore the morphology of the interdental adhesion area; S33. Calculate the average curvature of the wax occlusion record model, extract the points with curvature values ​​within a given range as the boundaries of the occlusal pits of each tooth, and then obtain the boundaries of the occlusal pits of each tooth based on morphological methods and skeleton extraction methods. S34. By registering each segmented tooth and its corresponding occlusal pit, the current position of the patient's teeth can be restored, and the time T can be obtained. N A model of tooth position; S4. The complete dental arch model obtained at overlapping time T0 and time T N The tooth position model is obtained, an overlapping model is acquired, and a local three-dimensional coordinate system is established for each tooth; specifically, S41. Based on the morphological characteristics of a single tooth crown, extract the feature regions corresponding to the incisal ridge and cusp ridge on the tooth crown according to the given average curvature threshold. S42. Then, the feature region is fitted using the eigenvalue decomposition method, and the transformation is adjusted to obtain the local reference plane F0 on a single tooth crown. S43. Interactively select the width direction of all crowns and calculate their axial bounding box. Select the center of the quadrilateral whose crown bounding box coincides with the local reference plane F0 as the origin of the local coordinate system, the width direction as the local coordinate principal axis u, and the axis that coincides with the normal of the local coordinate plane as the w axis. The v axis can be determined according to the right-hand rule. S5. Using the overlap model and local three-dimensional coordinate system obtained in step S4, perform single tooth overlap analysis and calculate the three-dimensional movement data of the tooth. S6. Repeat step S5 until the three-dimensional movement data of all teeth in the dentition are obtained through analysis.

2. The orthodontic tooth movement monitoring method based on wax occlusion recording as described in claim 1, characterized in that: It also includes step S7, in which T data are continuously collected at different times during the orthodontic treatment of the patient through steps S1 to S5. N The wax bite record was recorded and analyzed to obtain the position information and three-dimensional movement record of all the patient's teeth throughout the entire orthodontic cycle.

3. The orthodontic tooth movement monitoring method based on wax occlusion recording as described in any one of claims 1-2, characterized in that: In step S2, time T is obtained. N The wax occlusion record is obtained by heating a wax sheet into a horseshoe shape, placing it on the lower dental arch, biting down, and then slowly removing the wax sheet after it cools and hardens. After confirming that the tooth imprint is intact and the wax sheet is not deformed, the wax occlusion record is obtained by rinsing with water and drying it.

4. The orthodontic tooth movement monitoring method based on wax occlusion recording as described in any one of claims 1-2, characterized in that: In step S5, the three-dimensional movement data of the teeth includes the tooth movement distance and the tooth movement angle. The tooth movement distance includes the elongation / intrusion distance, the labial / lingual movement distance, and the mesial / distal movement distance. The tooth movement angle includes the torsion angle, the mesial / distal tilt angle, and the labial / lingual tilt angle.

5. A system for implementing the orthodontic tooth movement monitoring method based on wax occlusion recording as described in any one of claims 1-4, characterized in that: Includes 3D model acquisition terminals and monitoring terminals. 3D model acquisition terminal: Obtaining the time T before orthodontic treatment from occlusal wax films. N The wax bite record was obtained by a 3D scanner at time T. N The wax bite record is optically scanned to obtain a three-dimensional digital model of the bite record, which is then sent to the monitoring terminal via a communication module. The monitoring terminal includes a complete model generation module and a location monitoring module. Complete model generation module: An intraoral scanning model of the dentition of the patient at time T0 during orthodontic treatment is obtained using an intraoral scanner, and a cone-beam CT tooth model is obtained using an oral cone-beam CT device; the obtained intraoral scanning model and cone-beam CT tooth model are superimposed to obtain a complete dentition model including the crowns and roots; Position monitoring module: Matches the obtained occlusal record 3D digital model with the complete dentition model to reconstruct the time T. N Tooth position model; complete tooth row model obtained by overlapping time T0 and time T N The tooth position model is obtained, and a local three-dimensional coordinate system is established for each tooth; the position movement data of the teeth are calculated by using the obtained overlapping tooth position model and local three-dimensional coordinate system.

6. The system as described in claim 5, characterized in that: In the 3D model acquisition terminal, a handheld 3D scanner is used to measure time T. N Optical scanning was performed on the wax bite record to obtain a three-dimensional digital model of the bite record.

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