Real-time cbct-guided centric relation determination method, system, device, and storage medium

Abstract

The application discloses a kind of real-time CBCT guided centric relation determination method, system, equipment and storage medium. Upper and lower jaw dental arch and jaw three-dimensional data are obtained by intraoral scanning and CBCT scanning, and a virtual patient model is fitted and established;Obtain the spatial position relationship between motion acquisition marker and patient dentition;Use probe to pick up dental arch feature points, establish the spatial mapping relationship from motion acquisition marker to CBCT coordinate system;Real-time tracking of marker position is realized through electronic facebow system, and the position of condyle in glenoid cavity is dynamically displayed in real time on CBCT image based on spatial mapping relationship;Under the guidance of real-time visualization, the clinician preliminarily determines the centric relation position candidate in combination with clinical method;Guide the patient to carry out joint function movement, and monitor the joint function and masticatory muscle activity synchronously, and determine the final centric relation position after verifying the health of temporomandibular joint function.The application realizes chair-side real-time visualization and function verification, and significantly improves the diagnosis and treatment efficiency of jaw position determination.

Description

Technical Field

[0001] This application relates to the field of digital oral treatment technology, specifically to a method, system, device, and storage medium for determining centric relationships under real-time CBCT guidance. Background Technology

[0002] The centric relation (CR) is a crucial reference jaw position used in dentistry for the treatment of temporomandibular joint disorders, occlusal reconstruction, and orthodontics. An ideal CR position ensures that both condyles are centrally located, stable, and reproducible within the glenoid fossa, while maintaining healthy temporomandibular joint movement and coordinated masticatory muscle function in this position.

[0003] Currently, clinical methods for determining the midline relationship mainly fall into two categories: traditional techniques and digital technologies. Traditional techniques rely on the physician's experience and tactile sense, such as the swallowing and biting maneuver, the muscle closure pathway endpoint method, Dawson's method, and the foliate guide method. Although these methods have been used in long-term clinical practice, their results are greatly affected by the operator's skill level and the patient's cooperation, resulting in poor repeatability and high subjectivity and instability.

[0004] In recent years, with the development of digital technology, various methods for determining jaw position have emerged based on electronic facebows, CBCT (cone-beam computed tomography), and intraoral scans. For example, the electronic facebow method records the patient's mandibular movement trajectory and selects a position on the movement path as the CR position. However, this method relies on the patient's joint movement trajectory being healthy; if the patient has pre-existing joint pathology, the obtained jaw position may be inapplicable. Another method combines CBCT and intraoral scan data to directly adjust the mandibular position in a three-dimensional virtual environment to optimize the condyle's position in the glenoid fossa, achieving visualized jaw position design. However, this method ignores the presence of soft tissues such as the articular disc and ligaments; jaw positions designed solely based on bony structures may not be achievable during actual intraoral occlusion or may lead to joint dysfunction.

[0005] Although some scholars have attempted to combine electronic facebow tracing with CBCT 3D reconstruction to fine-tune the jaw position based on the patient's actual movements and improve its feasibility, existing digital methods still suffer from a common problem—validation lag. That is, after the jaw position design is completed, subsequent clinical examinations (such as joint palpation, auscultation, and electromyography) or repeat CBCT scans are still needed to verify the feasibility and good joint function of the position. If validation fails, a redesign is required, leading to prolonged treatment cycles, multiple patient follow-ups, and wasted medical resources.

[0006] Therefore, there is an urgent need in the existing technology for a method and system for determining the centric relationship that can complete data acquisition, jaw position design and functional verification in real time and synchronously at the chairside. Summary of the Invention

[0007] To address the problems of strong operational dependence, invisible soft tissue, delayed verification, and poor repeatability in existing technologies, this invention provides a method, system, device, and storage medium for determining the midline relationship under real-time CBCT guidance, thereby resolving the aforementioned technical deficiencies.

[0008] In a first aspect, the present invention proposes a method for determining the midline relationship guided by real-time CBCT, comprising the following steps:

[0009] S1. Obtain three-dimensional data of the maxillary and mandibular dental arches through intraoral scanning, obtain three-dimensional data of the maxillary and mandibular bones through CBCT scanning, fit the three-dimensional data of the maxillary and mandibular dental arches with the three-dimensional data of the maxillary and mandibular bones, and establish a virtual patient model.

[0010] S2. Adhere motion acquisition markers to the patient's dentition and obtain the spatial relationship between the motion acquisition markers and the patient's dentition;

[0011] S3. Based on the virtual patient model and spatial position relationship, use the probe to take dental arch feature points and establish the spatial mapping relationship between motion acquisition markers and CBCT coordinate system.

[0012] S4. The position of motion acquisition markers is tracked in real time through the electronic face bow system. Based on the spatial mapping relationship, a three-dimensional model of the mandible and jawbone is rendered in real time on the CBCT image, and the position of the condyle in the glenoid fossa is dynamically displayed.

[0013] S5. While displaying the condyle position in real time, guide the patient to perform biting movements, and combine the centric relation jaw position guidance technique to initially determine a jaw position as a candidate for centric relation position;

[0014] S6. Starting from the candidate centric relation position, guide the patient to perform joint function movements, while monitoring joint function and masticatory muscle activity to verify whether the joint function is healthy under the jaw position. If healthy, determine the jaw position as the final centric relation position.

[0015] Preferably, in step S1, the three-dimensional data of the maxillary and mandibular dental arches are fitted with the three-dimensional data of the maxillary and mandibular bones to establish a virtual patient model, which specifically includes the following sub-steps:

[0016] S11. Based on bony anatomical landmarks, separate three-dimensional models of the maxilla and mandible containing condyles are segmented from the three-dimensional data of the maxilla and mandible.

[0017] S12. Register the three-dimensional data of the maxillary and mandibular dental arches with the corresponding three-dimensional models of the maxillary and mandibular bones step by step:

[0018] S121. Initial registration is performed based on anatomical landmarks. The three-dimensional data of the maxillary and mandibular dental arches are coarsely registered with the corresponding three-dimensional models of the maxillary and mandibular bones to obtain the initial registration position.

[0019] S122. Based on the initial registration position, and with the occlusal relationship of the intercuspal position as the constraint, the iterative nearest point algorithm is used for fine registration to complete the establishment of the virtual patient model.

[0020] Preferably, in step S3, based on the virtual patient model and spatial positional relationships, the dental arch feature points are obtained using a probe, and a spatial mapping relationship between the motion acquisition markers and the CBCT coordinate system is established, including the following sub-steps:

[0021] S31. Using the CBCT coordinate system as a reference, register the three-dimensional data of the maxillary dental arch with the three-dimensional model of the maxilla to obtain the first transformation matrix describing the position of the maxillary dental arch in CBCT space; register the three-dimensional model of the mandible with the three-dimensional data of the mandibular dental arch to obtain the second transformation matrix describing the relative spatial relationship between the mandibular dental arch and the mandible.

[0022] S32. Use a probe with optical positioning markers to collect multiple feature points of the maxillary and mandibular dental arches, and determine the third transformation matrix between the maxillary motion acquisition markers and the three-dimensional data of the maxillary dental arches, and the fourth transformation matrix between the mandibular motion acquisition markers and the three-dimensional data of the mandibular dental arches.

[0023] S33. Based on the first transformation matrix, the second transformation matrix, the third transformation matrix, and the fourth transformation matrix, a composite spatial mapping relationship F is synthesized to map the real-time spatial coordinates of motion acquisition markers to the CBCT coordinate system. The input of the composite spatial mapping relationship F is the real-time pose of the motion acquisition markers, and the output is the real-time pose of the mandible in the CBCT coordinate system. The motion acquisition markers include maxillary motion acquisition markers and mandibular motion acquisition markers.

[0024] More preferably, in step S4, the position of the motion acquisition marker is tracked in real time by the electronic face bow system, and a three-dimensional model of the maxilla and mandible is rendered in real time on the CBCT image based on the spatial mapping relationship. This specifically includes the following sub-steps:

[0025] S41. Using the binocular optical tracker of the electronic facebow system, the positions and orientations of the maxillary motion acquisition markers and mandibular motion acquisition markers in the coordinate system of the binocular optical tracker are acquired in real time, and the fifth transformation matrix and the sixth transformation matrix are obtained respectively.

[0026] S42. Take the fifth and sixth transformation matrices as inputs and substitute them into the composite spatial mapping relationship F synthesized in step S33 to calculate the real-time pose transformation matrix T of the mandible in the CBCT coordinate system.

[0027] S43. Based on the real-time posture transformation matrix T, update and render the projection contour lines of the three-dimensional model of the mandible and jawbone on the CBCT image in real time, dynamically display the position of the condyle in the glenoid fossa, and simultaneously record the mandibular movement trajectory data.

[0028] Preferably, in step S5, the centric relation occlusal guidance technique includes at least one of the following: swallowing bite method, natural bite method, anterior splint method, Dawson method, or foliate guide method.

[0029] Preferably, in step S6, joint function and masticatory muscle activity are monitored to verify whether the joint function is healthy under jaw position. If healthy, the jaw position is determined as the final centric relation position. This specifically includes the following sub-steps:

[0030] S61. Electrode pads were attached to the skin surface of the temporalis and masseter muscles on the left and right sides of the patient to collect surface electromyography signals.

[0031] S62. Align surface electromyography signals with mandibular movement trajectory data using timestamps to achieve synchronous acquisition and analysis;

[0032] S63. Based on surface electromyography signals and mandibular movement trajectory data, determine whether the submandibular joint function is healthy. If healthy, determine the mandibular position as the final centric relation position.

[0033] More preferably, in step S63, based on surface electromyography signals and mandibular movement trajectory data, the health of the mandibular joint function is determined, specifically including:

[0034] If the surface electromyography signal shows that the contraction of the masticatory muscles on the left and right sides is symmetrical, and the mandibular movement trajectory is smooth and there are no joint noises, then the joint function is considered healthy.

[0035] Secondly, this invention proposes a real-time CBCT-guided centric relation determination system for implementing the method described in any of the above claims, the system comprising:

[0036] The patient model building module is configured to acquire three-dimensional data of the maxillary and mandibular dental arches through intraoral scanning, acquire three-dimensional data of the maxillary and mandibular bones through CBCT scanning, and fit the three-dimensional data of the maxillary and mandibular dental arches with the three-dimensional data of the maxillary and mandibular bones to build a virtual patient model.

[0037] The data acquisition module is configured to bond motion acquisition markers to the patient's dentition and acquire the spatial positional relationship between the motion acquisition markers and the patient's dentition.

[0038] The spatial mapping module is configured to establish a spatial mapping relationship between motion acquisition markers and the CBCT coordinate system based on the virtual patient model and spatial position relationship, using the probe to capture dental arch feature points;

[0039] The real-time tracking and display module is configured to track the position of motion acquisition markers in real time through the electronic face bow system. Based on the spatial mapping relationship, it renders a three-dimensional model of the mandible and jawbone in real time on the CBCT image and dynamically displays the position of the condyle in the glenoid fossa.

[0040] The jaw position determination module is configured to guide the patient to perform biting actions while displaying the condyle position in real time. Combined with the centric relation jaw position guidance technique, a jaw position is initially determined as a candidate for centric relation position.

[0041] The jaw position verification module is configured to guide patients to perform joint function movements starting from the candidate centric relation position, while monitoring joint function and masticatory muscle activity to verify whether the joint function is healthy under jaw position. If healthy, the jaw position is determined as the final centric relation position.

[0042] Thirdly, the present invention proposes a terminal device, including a memory, a processor, and a computer program stored in the memory and capable of running on the processor, wherein the processor executes the computer program to implement the steps of any of the above-described real-time CBCT-guided centering relationship determination methods.

[0043] Fourthly, the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the real-time CBCT-guided centering relationship determination method as described in any of the preceding claims.

[0044] Compared with the prior art, the beneficial results of the present invention are as follows:

[0045] (1) Real-time visualization and verification at the chairside were realized, solving the problem of verification lag.

[0046] By integrating an improved electronic facebow system with real-time registration and rendering of CBCT data, this invention can dynamically display the precise location of the condyle within the glenoid fossa on CBCT images while the physician guides the procedure. This allows data acquisition, jaw positioning design, and preliminary anatomical location verification to be completed simultaneously at the chairside, without waiting for subsequent CBCT imaging or data processing. This completely changes the lag in the traditional digital workflow of "design-verification-redesign," significantly shortening the treatment cycle.

[0047] (2) It improves the accuracy and repeatability of jaw position determination and reduces the reliance on the physician's personal experience.

[0048] This invention establishes a precise virtual patient model and a series of spatial transformation matrices to map the patient's real-time mandibular movements onto the CBCT coordinate system with high fidelity. This method transforms subjective manual manipulation into objective, quantifiable three-dimensional spatial position data, making the determined jaw position no longer dependent on the physician's feel and experience. This significantly improves the consistency and repeatability of results between different operators and multiple operations by the same operator.

[0049] (3) Combining anatomical and functional standards ensures the physiological health of the determined jaw position.

[0050] This invention does not merely focus on the static anatomical position of the condyle within the glenoid fossa. Instead, it guides patients in functional movements while simultaneously monitoring joint murmurs and surface electromyographic signals of the masticatory muscles. By aligning and analyzing the mandibular movement trajectory with electromyographic activity on a time stamp basis, it is possible to comprehensively assess the motor function of the mandibular joint and the coordination of muscles in this position. This ensures that the determined midline relationship is not only anatomically sound but also functionally healthy, effectively avoiding the risk of correct anatomical position but functional abnormalities.

[0051] (4) The clinical operation process has been optimized, which has improved the efficiency of diagnosis and treatment and the patient experience.

[0052] This invention establishes a basic model through a single CBCT scan and intraoral scan, which can then be repeatedly used in subsequent jaw position identification and verification. This eliminates the need for patients to undergo repeated CBCT scans to verify jaw position, reducing patient radiation exposure and waiting time. Furthermore, by integrating multiple steps into a single visit, it simplifies the treatment process, saves time for both physicians and patients, and improves overall treatment efficiency and patient satisfaction.

[0053] (5) It has laid the foundation for future intelligent diagnosis and treatment and has great potential for expansion.

[0054] The real-time data acquisition and display system constructed in this invention provides an ideal data platform for the subsequent introduction of artificial intelligence algorithms. For example, based on a large amount of healthy jaw position data, an AI model can be trained to automatically identify and recommend the optimal condylar position; or motion trajectory analysis can be dynamically optimized through machine learning. This gives the technology broad scope for expansion and application prospects. Attached Figure Description

[0055] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments, taken with reference to the accompanying drawings:

[0056] Figure 1 This is a schematic diagram of the overall process of the real-time CBCT-guided method for determining the centering relationship according to the present invention;

[0057] Figure 2 This is a schematic diagram of the three-dimensional anatomical structure of the upper and lower jawbones and dental arch;

[0058] Figure 3 This is a diagram illustrating the wearing of a motion data collection marker;

[0059] Figure 4 This is a diagram illustrating patient registration scan data;

[0060] Figure 5 This is a schematic diagram showing the central position of the condyle during a normal interruption of occlusion;

[0061] Figure 6 This is a schematic diagram of electromyography (EMG) signal monitoring;

[0062] Figure 7 This is a schematic diagram of the interface for synchronous analysis of mandibular movement trajectory and surface electromyography signals;

[0063] Figure 8 This is a schematic diagram of the real-time CBCT-guided centering relationship determination system of the present invention;

[0064] Figure 9 This is a schematic diagram of the structure of a computer system suitable for implementing the embodiments of the present invention. Detailed Implementation

[0065] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0066] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0067] Figure 1 This diagram illustrates the overall flow of a real-time CBCT-guided method for determining the midline relationship according to the present invention. Figure 1 As shown, the method includes the following steps:

[0068] S1. Obtain three-dimensional data of the maxillary and mandibular dental arches through intraoral scanning, obtain three-dimensional data of the maxillary and mandibular bones through CBCT scanning, fit the three-dimensional data of the maxillary and mandibular dental arches with the three-dimensional data of the maxillary and mandibular bones, and establish a virtual patient model.

[0069] S2. Adhere motion acquisition markers to the patient's dentition and obtain the spatial relationship between the motion acquisition markers and the patient's dentition;

[0070] S3. Based on the virtual patient model and spatial position relationship, use the probe to take dental arch feature points and establish the spatial mapping relationship between motion acquisition markers and CBCT coordinate system.

[0071] S4. The position of motion acquisition markers is tracked in real time through the electronic face bow system. Based on the spatial mapping relationship, a three-dimensional model of the mandible and jawbone is rendered in real time on the CBCT image, and the position of the condyle in the glenoid fossa is dynamically displayed.

[0072] S5. While displaying the condyle position in real time, guide the patient to perform biting movements, and combine the centric relation jaw position guidance technique to initially determine a jaw position as a candidate for centric relation position;

[0073] S6. Starting from the candidate centric relation position, guide the patient to perform joint function movements, while monitoring joint function and masticatory muscle activity to verify whether the joint function is healthy under the jaw position. If healthy, determine the jaw position as the final centric relation position.

[0074] The following embodiments describe in detail the specific implementation process of a real-time CBCT-guided method for determining the midline relationship. This method simultaneously completes data acquisition, visual guidance, and functional verification during clinical chairside operation, effectively solving the problems of verification lag and strong operational dependence in the prior art.

[0075] (1) Data collection and virtual patient modeling stage

[0076] First, initial data acquisition is performed. A high-precision intraoral scanner (e.g., a 3shape intraoral scanner) is used to scan the entire dental arch of the patient's upper and lower jaws, acquiring complete three-dimensional surface data of the dental arches. This data is output in STL format, forming the aforementioned three-dimensional data of the upper and lower jaw dental arches. The scan should ensure that all tooth structures, gingival margins, and adjacent relationships are included.

[0077] CBCT data acquisition was then performed. The patient was instructed to close their mouth in the intercuspal position, and an occlusal record was created using addition-cure silicone rubber material. This record accurately maintains the three-dimensional spatial relationship of the intercuspal position. In this occlusal state, a CBCT device (such as Kavo 3D eXam, scanning parameters: 120kV, 5mA, voxel size 0.25mm) was used for scanning. The scan range should completely include the bilateral temporomandibular joint regions, the entire dentition, and the jaw structure.

[0078] After obtaining the CBCT DICOM data, it was imported into medical image processing software (e.g., Materialise's Mimics Innovation Suite 25.0). First, 3D reconstruction was performed to generate initial 3D models of the maxilla and mandible. Using a region growing algorithm combined with manual correction, separate 3D models of the maxilla and mandible, including the condyles, were segmented from the reconstructed 3D volume data. The segmented models were exported in STL format, ensuring the models were complete and without broken surfaces.

[0079] Then, data fitting was performed to establish a unified virtual patient model. The maxillary and mandibular arch STL data obtained from the intraoral scanner were precisely registered with the corresponding jawbone STL data segmented by CBCT. This registration process employed an advanced step-by-step strategy:

[0080] First, initial registration (coarse registration) based on anatomical landmarks is performed. Obvious anatomical points of the dental tissues in the maxillary and mandibular dental arches, such as pits, fissures, cusps, and incisal edges, are selected and initially aligned with the corresponding areas of the maxillary bone model. This step uses the least squares method to achieve preliminary spatial matching and obtain the initial registration position.

[0081] Based on the initial registration, fine registration is performed. Using the intercuspal occlusal relationship as a rigid spatial constraint, the Iterative Closest Point (ICP) algorithm is employed for precise registration. The specific implementation of the ICP algorithm includes the following steps:

[0082] a. Search for the nearest point pair to the source point cloud (dental arch data) in the target point cloud (jawbone data);

[0083] b. Calculate the rigid body transformation matrix between these point pairs to minimize the mean square error;

[0084] c. Apply the transformation matrix to update the position of the source point cloud;

[0085] d. Iterate through the above process until the mean square error is less than the preset threshold (e.g., 0.1 mm) or the maximum number of iterations is reached.

[0086] Through this process, the dental data and jawbone data achieve sub-millimeter spatial alignment accuracy, thereby completing the establishment of a high-precision virtual patient model.

[0087] Figure 2 A schematic diagram of the three-dimensional anatomy of the maxilla and mandible and dentition is shown for reference. Figure 2 It forms the skeletal basis of the virtual patient model, clearly demonstrating the three-dimensional anatomical structure of the maxilla, mandible, and dentition reconstructed from CBCT data, providing an accurate anatomical reference for subsequent spatial mapping and dynamic display.

[0088] (2) Calibration stage of motion tracking system

[0089] Figure 3 A schematic diagram of wearing a motion data acquisition device is shown. (For example...) Figure 3 As shown, after 30 seconds of phosphoric acid etching on the labial surfaces of the patient's maxillary right anterior teeth and mandibular left anterior teeth, a light-cured resin adhesive (such as 3M Filtek Ultimate) was used to fix the maxillary motion acquisition marker and mandibular motion acquisition marker, respectively. These motion acquisition markers allow for precise identification and positioning by the optical tracking system.

[0090] After the maxillary and mandibular motion acquisition markers were fixed, the maxillary and mandibular dental arches with the markers attached were scanned again using an intraoral scanner. The scan was performed in high-resolution mode to ensure clear acquisition of both the surface morphology of the dental arch and the complete three-dimensional shape of the markers attached to it, thus obtaining an STL file of the arch registration data with markers. During the scan, the relative positional relationship between the markers and the dentition was captured from multiple angles to ensure data integrity. This step established the spatial positional relationship between the motion acquisition markers and the patient's dentition, laying the foundation for the subsequent acquisition of mandibular movement relative to the maxilla by the electronic facebow system tracking these markers.

[0091] Figure 4 A schematic diagram of patient registration scan data is shown. (For example...) Figure 4 As shown, an intraoral scanner is used to scan the dental arch with the marker, obtain the STL data of the dental arch with the marker, and accurately register this data with the corresponding dental arch data without the marker in the virtual patient model to complete patient registration and establish the relationship between the marker and the CBCT coordinate system.

[0092] (3) Spatial mapping relationship establishment stage

[0093] The core of this stage is to establish a precise spatial mapping relationship between motion acquisition markers and the CBCT coordinate system. The specific registration process is as follows:

[0094] S31. Using the CBCT coordinate system as the absolute spatial reference, perform precise ICP registration between the 3D data of the maxillary dental arch in the virtual patient model and the 3D model of the maxilla, obtaining the first transformation matrix T1 describing the position of the maxillary dental arch in CBCT space. This matrix is ​​a 4×4 homogeneous transformation matrix containing rotation and translation components. Simultaneously, perform ICP registration between the 3D model of the mandible and the 3D data of the mandibular dental arch, obtaining the second transformation matrix T2 describing the relative spatial relationship between the mandibular dental arch and the mandible.

[0095] S32. By using a probe to locate feature points such as tooth cusps, a spatial mapping relationship is established between the motion acquisition markers and the intraoral scanning and CBCT coordinate systems. Specifically, a dedicated probe with optical positioning markers is used. Its tip is precisely calibrated, and its position in space can be captured in real time by an optical tracking system with an accuracy of 0.1 mm. The probe tip is used to sequentially contact 7-8 feature points of the maxillary dental arch (including the incisal edges of the central incisors, lateral incisors, canine cusps, buccal cusps of the premolars, and mesobuccal cusps of the first molars), and the three-dimensional coordinates of these points in the maxillary motion acquisition marker coordinate system are recorded using electronic facebow software. Simultaneously, identical feature points are located manually or automatically in the marked maxillary dental arch STL data. Through spatial matching of the two sets of points, the singular value decomposition (SVD) algorithm is used to calculate the third transformation matrix T3 between the maxillary motion acquisition markers and the three-dimensional data of the maxillary dental arch. Similarly, by contacting the corresponding feature points of the mandibular dental arch with a probe, the fourth transformation matrix T4 between the mandibular motion acquisition marker and the three-dimensional data of the mandibular dental arch is calculated. The process described above, which involves taking the cusp feature points with a probe and calculating the transformation matrix, is the core step in establishing a precise spatial mapping relationship between the motion acquisition marker and the intraoral scan and CBCT coordinate system.

[0096] S33. Based on the above four transformation matrices (T1, T2, T3, T4), a composite spatial mapping relation F is synthesized through matrix multiplication. The composite spatial mapping relation F includes the maxillary mapping relation F_upper and the mandibular mapping relation F_lower, and its mathematical expression is:

[0097] F_upper = T1 × T3 -1

[0098] F_lower = T2 × T4 -1

[0099] The spatial mapping relationship F is a deterministic mathematical function whose input is the pose data of the motion acquisition markers acquired in real time, and whose output is the real-time pose of the mandible in the CBCT coordinate system. This spatial mapping relationship F is the core mathematical foundation for subsequent real-time visualization, ensuring the accurate mapping of motion data to CBCT space.

[0100] (4) Real-time tracking and dynamic display stage

[0101] This phase utilizes an improved electronic face bow system to achieve real-time dynamic visualization of condylar position.

[0102] S41. Activate the electronic facebow system. Its binocular optical tracker (such as NDI Polaris Vega, with an accuracy of 0.15mm and a sampling frequency of 20Hz) captures in real time the six-degree-of-freedom position and orientation (including three translational components and three rotational components) of the maxillary and mandibular motion acquisition markers attached to the patient's mouth in the tracker's own coordinate system, and obtains the fifth transformation matrix T5 (describing the pose of the maxillary motion acquisition marker in the tracker's coordinate system) and the sixth transformation matrix T6 (describing the pose of the mandibular motion acquisition marker in the tracker's coordinate system).

[0103] S42. Using the real-time acquired fifth transformation matrix T5 (pose of the maxillary motion acquisition marker in the optical coordinate system) and sixth transformation matrix T6 (pose of the mandibular motion acquisition marker in the optical coordinate system) as inputs, calculate the real-time pose transformation matrix T of the mandible in the CBCT coordinate system:

[0104] First, calculate the pose of the maxillary motion acquisition markers in the CBCT coordinate system:

[0105] P_cbct_upper = F_upper × T5.

[0106] Then, the pose of the mandibular motion acquisition marker in the CBCT coordinate system is calculated:

[0107] P_cbct_lower = F_lower × T6.

[0108] The real-time pose transformation matrix T of the mandible in the CBCT coordinate system is determined by the pose change of the mandibular landmark relative to the maxillary landmark, and the calculation formula is as follows:

[0109] T=F_lower × T6 × (F_upper × T5) -1

[0110] That is: T = T2 × T4 -1 ×T6×T5 -1 ×T3×T1 -1

[0111] The real-time pose transformation matrix T accurately describes the real-time position and angle changes of the mandible (including the condyle) relative to the CBCT coordinate system (and the fixed maxilla) during mandibular movement. The entire calculation process is performed on a graphics processing unit (GPU), ensuring a refresh rate of no less than 15Hz to meet real-time requirements.

[0112] S43. Based on the calculated real-time pose transformation matrix T, the projected contours of the maxilla and mandible 3D models are updated and rendered in real-time on the CBCT image background displayed on the monitor. Rendering is accelerated using OpenGL or DirectX graphics libraries, supporting multi-planar reconstruction (MPR) display, including simultaneous updates of the sagittal, coronal, and axial planes. This allows physicians to intuitively and dynamically display the positional changes of the condyle within the glenoid fossa. Figure 5 This image shows a schematic diagram of the condyle's centered position during a normal interrupted bite. The image reflects the spatial relationship between the condyle and the glenoid fossa in real time, providing physicians with intuitive anatomical position feedback. Simultaneously, the system records mandibular movement trajectory data at a frequency of 20Hz, including parameters such as condylar movement path, movement speed, and acceleration.

[0113] (5) Stage of determining the central relationship

[0114] With the aid of real-time visualization of the condyle position, the physician guides the patient to perform specific biting movements. The physician may combine one or more centric relation jaw positioning techniques, including but not limited to: swallowing bite (instructing the patient to swallow saliva and then close their mouth naturally under muscle guidance), natural bite (instructing the patient to fully relax their mandible and then slightly close their mouth), anterior splint method (placing a deprogrammed splint in the maxillary anterior region), Dawson method (the physician uses both hands to guide the patient's mandible to retract to the position of maximum joint capsule tension), or leaf guide method (using a leaf guide to position the mandible).

[0115] During the procedure, the physician closely observes key anatomical indicators on the screen, such as whether the condyle has moved to the centered position within the glenoid fossa, whether the bilateral joint spaces are symmetrical (anterior, superior, and posterior spaces), and whether the mandibular chin point is located on the midline of the face. When the ideal anatomical position is observed, this jaw position is initially determined as a candidate for the midline relation position.

[0116] (6) Functional verification and final determination stage

[0117] Starting with the initially determined candidate midline position, a comprehensive functional verification is conducted to ensure that the determined jaw position is not only anatomically reasonable but also functionally healthy.

[0118] S61. Four surface electromyography (sEMG) sensor electrode pads (such as the Delsys Trigno Wireless system) are attached to the skin surface of the temporalis muscle (anterior bundle) and masseter muscle (the most prominent part of the muscle belly) on both sides of the patient, according to the international 10-20 system standard positions. The skin is cleaned with alcohol before electrode attachment to reduce impedance. The system acquires surface electromyography signals at a sampling frequency of 2000 Hz to ensure that the full frequency domain characteristics of electromyographic activity are captured.

[0119] S62. Guide the patient to perform standardized joint function movements, starting from the midline position candidate, including: wide mouth opening (at least 40mm), left lateral movement (5-10mm), right lateral movement (5-10mm), and protrusion movement (5-10mm). The system simultaneously acquires mandibular movement trajectory data and sEMG signals, and strictly aligns them using a unified hardware timestamp (1ms accuracy) to achieve precise synchronous acquisition and analysis of the two types of data.

[0120] Figure 6 A schematic diagram of electromyography (EMG) signal monitoring is shown. (For example...) Figure 6 As shown, electrode pads were attached to the bilateral temporalis and masseter muscles to collect surface electromyographic signals in real time. The signals were then processed and converted into visualized electromyographic activity graphs to assess the functional status of the masticatory muscles.

[0121] Figure 7 A schematic diagram of the interface for synchronous analysis of mandibular movement trajectory and surface electromyography signals is shown. For example... Figure 7 As shown, the interface displays motion trajectory data and electromyographic signals aligned on the time axis, facilitating physicians' comprehensive analysis of the coordination between motor function and muscle activity.

[0122] S63. Based on the results of synchronous analysis, a multi-parameter comprehensive assessment is used to determine whether the jaw joint function is healthy in this jaw position. Specific criteria include: surface electromyography (EMG) signals showing symmetrical contraction of the masticatory muscles on both sides (the difference in EMG amplitude between the corresponding muscles on both sides does not exceed 15%), and smooth mandibular movement without tremors or pauses (the first derivative of the movement trajectory is continuous). Auscultation of the joint by the physician reveals no clicking or murmurs (joint sounds are recorded and analyzed using an electronic stethoscope). When all these conditions are met, the joint function is deemed healthy, and this jaw position can be determined as the final centric relation.

[0123] If the functional verification fails, the system provides detailed diagnostic information: for example, electromyographic asymmetry indicates muscle dysfunction, and uneven movement trajectory indicates joint movement disorder. Based on this objective data, the physician can immediately adjust the guiding technique, re-determine the candidate jaw position, and verify it again. The entire process is completed in real-time at the chairside, eliminating the need for multiple follow-up visits for the patient.

[0124] Once the final centric relationship is determined, the system can immediately output precise three-dimensional data for that jaw position, used for: 1) digital occlusal splint design, using 3D printing to create precise therapeutic occlusal splints; 2) guiding jaw position reconstruction in orthodontic treatment; and 3) jaw position determination in full-mouth restoration. All treatments are performed based on validated healthy jaw positions, ensuring the predictability of treatment outcomes.

[0125] Further reference Figure 8As an implementation of the above method, in a second aspect, the present invention provides an embodiment of the structure of a real-time CBCT-guided centering relationship determination system 200, which can be specifically applied to various electronic devices. The real-time CBCT-guided centering relationship determination system 200 includes the following modules:

[0126] The patient model building module 210 is configured to acquire three-dimensional data of the maxillary and mandibular dental arches through intraoral scanning, acquire three-dimensional data of the maxillary and mandibular bones through CBCT scanning, fit the three-dimensional data of the maxillary and mandibular dental arches with the three-dimensional data of the maxillary and mandibular bones, and build a virtual patient model.

[0127] The data acquisition module 220 is configured to bond motion acquisition markers to the patient's dentition and acquire the spatial positional relationship between the motion acquisition markers and the patient's dentition.

[0128] The spatial mapping module 230 is configured to establish a spatial mapping relationship between motion acquisition markers and the CBCT coordinate system based on the virtual patient model and spatial position relationship, using a probe to capture dental arch feature points;

[0129] The real-time tracking and display module 240 is configured to track the position of motion acquisition markers in real time through the electronic face bow system, and render a three-dimensional model of the mandible and jawbone in real time on the CBCT image based on the spatial mapping relationship, and dynamically display the position of the condyle in the glenoid fossa.

[0130] The jaw position determination module 250 is configured to guide the patient to perform biting actions while displaying the condyle position in real time, and to preliminarily determine a jaw position as a candidate for centric relation position by combining the jaw position guidance technique for centric relation position.

[0131] The jaw position verification module 260 is configured to guide the patient to perform joint function movements starting from the candidate centric relation position, while monitoring joint function and masticatory muscle activity to verify whether the joint function is healthy under jaw position. If healthy, the jaw position is determined as the final centric relation position.

[0132] Thirdly, the present invention proposes a terminal device, including a memory, a processor, and a computer program stored in the memory and capable of running on the processor, wherein the processor executes the computer program to implement the steps of any of the above-described real-time CBCT-guided centering relationship determination methods.

[0133] Fourthly, the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the real-time CBCT-guided centering relationship determination method as described in any of the preceding claims.

[0134] The following is for reference. Figure 9It shows a schematic diagram of the structure of a computer system 300 suitable for implementing terminal devices or servers in the embodiments of this application. Figure 9 The terminal device or server shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of this application.

[0135] like Figure 9 As shown, the computer system 300 includes a central processing unit (CPU) 301, which can perform various appropriate actions and processes based on programs stored in read-only memory (ROM) 302 or programs loaded from storage section 308 into random access memory (RAM) 303. The RAM 303 also stores various programs and data required for the operation of the computer system 300. The CPU 301, ROM 302, and RAM 303 are interconnected via a bus 304. An input / output (I / O) interface 305 is also connected to the bus 304.

[0136] The following components are connected to I / O interface 305: an input section 306 including a keyboard, mouse, etc.; an output section 307 including a liquid crystal display (LCD) and speakers, etc.; a storage section 308 including a hard disk, etc.; and a communication section 309 including a network interface card such as a LAN card and a modem, etc. The communication section 309 performs communication processing via a network such as the Internet. A drive 310 is also connected to I / O interface 305 as needed. A removable medium 311, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on drive 310 as needed so that computer programs read from it can be installed into storage section 308 as needed.

[0137] Specifically, according to embodiments of this disclosure, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of this disclosure include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 309, and / or installed from removable medium 311. When the computer program is executed by central processing unit (CPU) 301, it performs the functions defined in the methods of this application. It should be noted that the computer-readable medium described in this application can be a computer-readable signal medium or a computer-readable medium or any combination thereof. The computer-readable medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this application, a computer-readable medium can be any tangible medium containing or storing a program that can be used by or in connection with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable medium that can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. Program code contained on a computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0138] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0139] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0140] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A real-time CBCT-guided centric relation determination system, characterized in that, The system comprises: A patient model establishing module configured to acquire three-dimensional data of upper and lower dental arches through intraoral scanning, acquire three-dimensional data of upper and lower jaws through CBCT scanning, fit the three-dimensional data of upper and lower dental arches with the three-dimensional data of upper and lower jaws, and establish a virtual patient model; A data acquisition module configured to adhere motion acquisition markers to a patient's dentition and acquire spatial position relationships between the motion acquisition markers and the patient's dentition; A spatial mapping module configured to utilize a stylus to pick up characteristic points of the dental arches based on the virtual patient model and the spatial position relationships, and establish a spatial mapping relationship of the motion acquisition markers to a CBCT coordinate system, comprising: registering the three-dimensional data of the upper dental arch with the three-dimensional model of the upper jaw based on the CBCT coordinate system to obtain a first conversion matrix describing the position of the upper dental arch in the CBCT space; and registering the three-dimensional model of the lower jaw with the three-dimensional data of the lower dental arch to obtain a second conversion matrix describing the relative spatial relationship between the lower dental arch and the lower jaw; acquiring a plurality of characteristic points of the upper and lower dental arches by using a stylus with an optical positioning marker, determining a third conversion matrix between the upper motion acquisition marker and the three-dimensional data of the upper dental arch, and determining a fourth conversion matrix between the lower motion acquisition marker and the three-dimensional data of the lower dental arch; based on the first conversion matrix, the second conversion matrix, the third conversion matrix, and the fourth conversion matrix, synthesizing a composite spatial mapping relationship F for mapping real-time spatial coordinates of the motion acquisition markers to the CBCT coordinate system, wherein the input of the composite spatial mapping relationship F is the real-time pose of the motion acquisition markers, and the output is the real-time pose of the lower jaw in the CBCT coordinate system, wherein the motion acquisition markers include the upper motion acquisition marker and the lower motion acquisition marker; A real-time tracking display module configured to track the positions of the motion acquisition markers in real time through an electronic facebow system, render three-dimensional models of the upper and lower jaws on a CBCT image in real time based on the spatial mapping relationship, and dynamically display the position of the condyle in the glenoid cavity, comprising: acquiring the positions and poses of the upper motion acquisition marker and the lower motion acquisition marker in the binocular optical tracker coordinate system of the electronic facebow system in real time by a binocular optical tracker of the electronic facebow system, and obtaining a fifth conversion matrix and a sixth conversion matrix, respectively; inputting the fifth conversion matrix and the sixth conversion matrix as inputs into the composite spatial mapping relationship F synthesized in step S33, and calculating a real-time pose transformation matrix T of the lower jaw in the CBCT coordinate system; updating and rendering the projection contour lines of the three-dimensional models of the upper and lower jaws on the CBCT image in real time according to the real-time pose transformation matrix T, dynamically displaying the position of the condyle in the glenoid cavity, and synchronously recording the lower jaw motion trajectory data; A jaw position determining module configured to preliminarily determine a jaw position as a candidate for the centric relation position while displaying the position of the condyle in real time, and guide the patient to perform a bite action in combination with a centric relation jaw position guiding method. The jaw position verification module is configured to guide the patient to perform joint function movement while monitoring joint function and masticatory muscle activity, verify whether the joint function under the jaw position is healthy, and determine the jaw position as the final centric relation position if the joint function is healthy.

2. The real-time CBCT-guided centric relation determination system of claim 1, wherein, In the patient model establishment module, the upper and lower arch three-dimensional data and the upper and lower jaw three-dimensional data are fitted to establish a virtual patient model, specifically including: Separating an independent upper jaw three-dimensional model and a lower jaw three-dimensional model containing condylar processes from the upper and lower jaw three-dimensional data based on bony anatomical landmarks; Step-by-step registration of the upper and lower arch three-dimensional data and the corresponding upper and lower jaw three-dimensional models is performed: Initial registration based on anatomical landmark points is performed to coarsely register the upper and lower arch three-dimensional data and the corresponding upper and lower jaw three-dimensional models to obtain an initial registration position; Based on the initial registration position, fine registration is performed using an iterative closest point algorithm with the intercuspal occlusion relationship as a constraint condition to complete the establishment of the virtual patient model.

3. The real-time CBCT-guided centric relation determination system of claim 1, wherein, In the jaw position determination module, the centric relation jaw position guiding method includes at least one of the swallowing occlusion method, the natural occlusion method, the front tooth splint method, the Dawson method, or the leaf-shaped gauge method.

4. The real-time CBCT-guided centric relation determination system of claim 1, wherein, In the jaw position verification module, the joint function and masticatory muscle activity are monitored to verify whether the joint function under the jaw position is healthy, and the jaw position is determined as the final centric relation position if the joint function is healthy, specifically including: Electrode patches are attached to the skin surfaces of the left and right temporal muscles and masseter muscles of the patient to collect surface electromyography signals; The surface electromyography signals and the mandibular movement trajectory data are aligned through timestamps to realize synchronous collection and analysis; Based on the surface electromyography signals and the mandibular movement trajectory data, it is determined whether the joint function under the jaw position is healthy, and the jaw position is determined as the final centric relation position if the joint function is healthy.

5. The real-time CBCT-guided centric relation determination system of claim 4, wherein, Based on the surface electromyography signals and the mandibular movement trajectory data, it is determined whether the joint function under the jaw position is healthy, specifically including: If the surface electromyography signals show that the left and right masticatory muscle contraction degrees are symmetrical, and the mandibular movement trajectory is smooth and the joint has no noise, it is determined that the joint function is healthy.

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