A digital complete denture preparation method based on precise mandibular positioning

Abstract

The present invention discloses a method for preparing digital complete dentures based on precise mandibular positioning, belonging to the technical field of denture preparation. The above preparation method includes the following steps: S1: Obtain oral data; S2: Perform digital design and adjust the jaw position through 3D editing software; S3: Design a jaw guide plate with a tray function through anatomical missing teeth and arrange teeth; S4: Prepare a fine impression and obtain an occlusion record; S5: Design and prepare complete dentures according to the edentulous jaw data and occlusion record. The present invention solves the problems that patients with tooth loss are difficult to obtain accurate occlusal relationships, the process is complex, and the technical sensitivity is high. It provides a method for directly moving the condyle and mandible on the clear and visual three-dimensional relationship of the glenoid fossa, condyle and mandible to obtain a therapeutic jaw position, and can directly use the adjusted mandibular position to prepare complete dentures through digital design. The obtained complete denture data is accurate, the preparation operation is simple, and the technical sensitivity is low.

Description

Technical Field

[0001] The present invention relates to the technical field of denture preparation, and particularly relates to a digital complete denture preparation method based on accurate mandibular positioning. Background Art

[0002] With the aggravation of aging, the number of patients with edentulous jaws has increased. Due to the loss of the cusp-fossa locking function of the upper and lower jaws in edentulous patients, the positional relationship between the mandible and the maxilla cannot be determined. Moreover, edentulism can lead to degenerative changes in the bone structure of the temporomandibular joint, the morphology of the condyle and the mandibular fossa will change, and the bone density will also be affected. Some studies have observed that the condyles of edentulous patients move backward and upward, the mandible rotates forward and upward, and the articular disc also moves forward accordingly.

[0003] Edentulous patients need to find a suitable mandibular position for the restoration of complete dentures. Traditional complete denture restoration techniques mostly rely on doctors to determine the occlusal relationship between the upper and lower jaws based on experience, and repeated impression making is required. The process is complex, the technical sensitivity is high, and improper impression taking and improper occlusal relationship may lead to the aggravation of the condition. Summary of the Invention

[0004] In order to solve the above technical problems, the object of the present invention is to provide a digital complete denture preparation method based on accurate mandibular positioning to solve the problems that it is difficult to accurately determine the positional relationships of the mandible, condyle and articular fossa in existing edentulous patients, and it is difficult to obtain the occlusal relationship between the upper and lower jaws with poor accuracy.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A digital complete denture preparation method based on accurate mandibular positioning includes the following steps:

[0007] S1: Data acquisition: Perform CBCT and intraoral optical scans on the patient respectively to obtain the craniofacial CBCT data and the edentulous jaw data of the upper and lower jaws of the patient;

[0008] S2: Digital design of jaw position: First, import the craniofacial CBCT data obtained in S1 into three-dimensional editing software for three-dimensional reconstruction, segment to obtain the maxilla data with the articular fossa and the edentulous maxilla, and the mandible data with the condyle and the edentulous mandible, then perform registration of the edentulous jaw data of the upper and lower jaws obtained in S1, and finally perform jaw position adjustment to obtain the adjusted edentulous jaw data of the upper and lower jaws;

[0009] S3: Making the jaw guide plate and arranging teeth: First, design the jaw guide plate based on the adjusted edentulous jaw data of the upper and lower jaws obtained through S2. Among them, for the upper dental arch, design from the right upper second molar to the left upper second molar, and for the lower dental arch, design from the right lower canine to the left lower canine or from the right lower second molar to the left lower second molar to obtain the anatomical missing tooth structure. Then, connect the anatomical missing teeth in the tooth defect area into a whole through the gingiva design module, design fixing pins in the gingiva of the posterior mandibular area or lower the anatomical missing tooth structure in the posterior mandibular area to form an occlusion and aesthetics confirmation device. Then, arrange the teeth according to the three-dimensional spatial position of the teeth, and finally make the jaw guide plate according to the data after tooth arrangement;

[0010] S4: Preparing the fine impression and confirming the jaw position and aesthetic relationship: Prepare the fine impressions of the upper and lower jaws through the jaw guide plate obtained in S3, and obtain the occlusion record data in the posterior tooth area after occlusion;

[0011] S5: Preparing the complete denture: Scan the fine impression obtained in S4 to get the edentulous jaw data of the complete denture, and fit it with the occlusion record data to obtain the complete denture data, and then make it through 3D printing or machining.

[0012] The beneficial effects of the present invention are as follows: Aiming at the problems that it is difficult for patients with tooth loss to obtain an accurate occlusion relationship, the acquisition process is complex, and the technical sensitivity is high, the present invention provides a method for directly moving the condyle and the mandible at the three-dimensional positions of the articular fossa, condyle and mandible with clear visualization to obtain the therapeutic jaw position, and can directly design and make the complete denture by digital method according to the adjusted mandibular position, with simple operation and low technical sensitivity.

[0013] Further, in S1, before performing CBCT and intraoral optical scanning, adhere fluid resin to the alveolar ridge mucosa of the patient to form a small vertebral shape.

[0014] Further, in S1, the CBCT data of the patient's craniofacial jaw is DICOM data, and the edentulous jaw data of the upper and lower jaws is STL data.

[0015] Further, in S2, the jaw position adjustment is carried out through the following steps:

[0016] First, align the mental point position of the mandible with the midfacial line, the mandibular angle points are on the same horizontal line when the mandibular angle is at a 40-50° elevation, the positions of the bilateral condyles are symmetric, and the mandible is centered. Then, confirm that the condyle position is located within the articular fossa. Then, adjust the jaw to the lateral view, and based on the orbital axis plane, adjust the position of the mandible until the angle formed by the mandibular plane angle and the orbital axis plane is 20-30°. Finally, adjust the vertical distance between the upper and lower jaws in the plane where the midfacial line is located to be 12-18 mm.

[0017] The beneficial effects of adopting the above further technical solution are as follows: By adjusting the gonion, condylar position, mandibular position, and the relative distance between the upper and lower jaws, the present invention obtains a suitable restoration space for complete dentures and the initial clear and visual digital three-dimensional positions of the glenoid fossa, condyle, and mandible.

[0018] Further, in S3, a occlusal plane plate with an angle of 0-25° is used for tooth arrangement, and the three-dimensional spatial position of the teeth is designed according to the following formula:

[0019] X = a + b + c;

[0020] In the formula, X is the protrusive condylar path inclination, a is the angle of the occlusal plane plate, b is the cusp inclination, and d is the posterior tooth separation angle.

[0021] The beneficial effects of adopting the above further technical solution are as follows: The present invention uses an angled occlusal plane plate for tooth arrangement for the digitally designed jaw guide plate. According to the calculation formula of the three-dimensional spatial position of the teeth, it can ensure the accuracy and aesthetics of tooth arrangement, without the need to transfer the jaw relationship and use a physical articulator, and the operation is simple.

[0022] Further, in S3, the preparation method of the jaw guide plate is numerical control cutting or 3D printing.

[0023] Further, in S3, the gingiva design module is a built-in module in three-dimensional editing software.

[0024] Further, in S4, the occlusal record data is obtained through the following steps:

[0025] First, the silicone rubber is fixed through the retention pins designed on the gingiva in the posterior tooth area of the mandible of the jaw guide plate, and then the upper and lower dentition obtained after fine impression is occluded, with the midlines of the upper and lower dentition aligned, and the occlusal record data is obtained in the posterior tooth area.

[0026] Further, after the occlusal record data in S4 is obtained, it is determined whether the patient's jaw position and aesthetic relationship are appropriate, and the mandible is adjusted.

[0027] Further, in S4, the fine impression can also be prepared by directly scanning the data with an intraoral scanner after the patient wears the jaw guide plate.

[0028] The beneficial effects of adopting the above further technical solution are as follows: The present invention installs silicone rubber in the anatomically missing tooth area of the fine impression of the edentulous area for the occlusal record test, with high data acquisition efficiency and accurate data. At the same time, the jaw position and aesthetic relationship of the patient's teeth can be adjusted quickly in real time according to the acquired data.

[0029] A digital complete denture based on accurate mandibular positioning is prepared by using the above preparation method.

[0030] The present invention has the following beneficial effects:

[0031] The present invention provides a digital preparation method for complete dentures based on precise mandibular positioning. This preparation method does not require repeated preparation of physical impressions, does not require transfer of jaw relation and the use of physical articulators, is easy to operate, has strong repeatability, and the design and fabrication of complete dentures can directly replicate the occlusal and aesthetic relations confirmed in the mouth, with easy operation and low technical sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a flow chart of the digital preparation of complete dentures based on precise mandibular positioning according to the present invention;

[0033] Figure 2 is a schematic diagram of tooth arrangement design using an angled occlusal plane plate in S3 of the present invention, where a is an edentulous jaw guide plate before tooth arrangement, and b is a schematic diagram after tooth arrangement using an angled occlusal plane plate;

[0034] Figure 3 is a three-dimensional front view of the jaw guide plate with tray function prepared in S3 of the present invention;

[0035] Figure 4 is a schematic diagram of the process of obtaining occlusal record data and confirming occlusal aesthetics in S4 of the present invention; where a is a schematic diagram of the tooth occlusion model before obtaining occlusal record data and confirming occlusal aesthetics, and b is a schematic diagram of the tooth occlusion model during the process of obtaining occlusal record data and confirming occlusal aesthetics. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention. For those not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are followed. The reagents or instruments not specified by the manufacturer are all conventional products that can be obtained through commercial purchase.

[0037] Example:

[0038] A digital preparation method for complete dentures based on precise mandibular positioning (the preparation flow chart is as Figure 1 shown), including the following steps:

[0039] S1: Obtaining initial diagnosis data

[0040] Bond fluid resin on the alveolar ridge mucosa of the patient to form a small conical shape for later positioning, and then perform CBCT and intraoral optical scans on the patient respectively to obtain DICOM data of the patient's craniofacial region (including the temporomandibular joint and the complete mandibular bone region) by CBCT and STL data of the edentulous jaws of the upper and lower jaws.

[0041] S2: Digitally design the therapeutic jaw position

[0042] First, import the DICOM data of the CBCT obtained in S1 into a 3D editing software (EXOCAD software) for 3D reconstruction. Segment the maxilla data of the edentulous maxilla with the glenoid fossa and the mandible data of the edentulous mandible with the condyle. In the software, use the same fluid resin cone data to register the obtained maxilla and mandible data with the STL data of the edentulous maxilla and mandible obtained in S1;

[0043] Then, perform jaw position adjustment. First, adjust the horizontal position in the 3D space. Align the pogonion position of the mandible with the midfacial line. The gonion points of the mandible are on the same horizontal line when the mandible is at a 45° elevation. When looking up from the bottom, the positions of the bilateral condyles are symmetric. Adjust the mandible to the central position without deviation. Then, confirm that the condyle position is within the glenoid fossa. Finally, adjust the jaws to the lateral view (bilateral condyles coincide, bilateral orbits coincide). Taking the orbital axis plane as the reference, adjust the position of the mandible until the angle formed by the mandibular plane angle and the orbital axis plane is 25°. In the frontal view, measure the vertical distance between the maxilla and mandible using the plane where the midfacial line is located to ensure that the vertical distance between the maxilla and mandible is 15 mm, obtaining a suitable space for complete denture restoration and completing the adjustment of the mandibular position;

[0044] Finally, place the articulator baseplate on the reference plane (select different reference planes according to different types of articulators), and directly export the adjusted edentulous maxilla and mandible data (maxilla with articulator baseplate data) in STL format.

[0045] S3: Prepare the jaw guidance plate and arrange teeth

[0046] Directly use the adjusted maxilla and mandible data in S2 to design the jaw guidance plate with tray function and arrange teeth using the fixed design module (fixed dental prosthesis design mode in EXOCAD software). First, design the anatomically missing teeth on the edentulous maxilla and mandible data. Design the maxillary dentition from the right maxillary second molar to the left maxillary second molar, and only design the mandibular dentition from the right mandibular canine to the left mandibular canine;

[0047] Then, through the gingiva design module (the gingiva design module built in EXOCAD software), connect the anatomically missing teeth in each tooth - missing area into a whole, and design retention pins on the gingiva in the posterior mandibular area for the retention of the bite - registration silicone rubber, forming a bite and aesthetic confirmation device. At the same time, the edge of this device is 2 mm shorter than the baseplate edge, and it is 2 mm posterior to the palatine fovea on the maxillary palate for subsequent impression preparation;

[0048] Then, use the angled occlusal plane plate (5 - 25°) to guide the tooth arrangement. The 3D spatial position of the teeth is designed according to the following formula (as shown in Figure 2 ):

[0049] X = a + b + c;

[0050] In the formula, X is the protrusive condylar path inclination, a is the angle of the occlusal plane plate, b is the cusp inclination, and d is the posterior tooth separation angle.

[0051] Finally, the STL format data of the jaw guide plate after tooth arrangement is imported into a numerical control cutting machine or a 3D printer for preparation to obtain a jaw guide plate with a tray function, and the three-dimensional front view is as Figure 3 shown.

[0052] S4: Preparation of fine impressions and confirmation of jaw position and aesthetic relationship

[0053] Using the jaw guide plate with a tray function prepared in S3 to take upper and lower jaw fine impressions. After taking the fine impressions, directly occlude the upper and lower dental arches, align the midlines of the upper and lower dental arches, install silicone rubber on the fixing pins in the posterior tooth area, obtain occlusal record data, and determine whether the patient's jaw position and aesthetic relationship are appropriate (the confirmation process of the occlusal record data and the occlusal aesthetic relationship is as Figure 4 shown), and perform proofreading and adjustment.

[0054] S5: Scan the fine impressions prepared in S4 and the occlusal data records (or the occlusal record data after proofreading the jaw position and aesthetic relationship) for data fitting to obtain the STL format data of the final complete denture, and obtain a digital complete denture based on accurate mandibular positioning through 3D printing or cutting preparation.

[0055] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A digital complete denture preparation method based on precise mandibular positioning, characterized in that, It includes the following steps: S1: Data acquisition: CBCT and intraoral optical scans are performed on the patient to obtain the patient's cranio-maxillofacial CBCT data and the edentulous maxilla and mandible data. S2: Digital design of jaw position: First, the cranio-maxillofacial CBCT data obtained in S1 is imported into 3D editing software for 3D reconstruction. The maxilla data with the glenoid fossa and edentulous maxilla and the mandible data with the condyle and edentulous mandible are segmented. Then, the registration of the edentulous maxilla and mandible data obtained in S1 is performed. Finally, the jaw position is adjusted to obtain the adjusted edentulous maxilla and mandible data. S3: Fabrication of jaw position guide plate and tooth arrangement: First, the adjusted edentulous maxilla and mandible data obtained through S2 are used for the design of the jaw position guide plate. Among them, the maxillary dentition is designed from the right maxillary second molar to the left maxillary second molar, and the mandibular dentition is designed from the right mandibular canine to the left mandibular canine or the mandibular dentition is designed from the right mandibular second molar to the left mandibular second molar to obtain the anatomical missing tooth structure. Then, the anatomical missing teeth in the tooth defect area are connected into a whole through the gingiva design module, and fixing pins are designed on the gingiva in the posterior mandibular tooth area or the anatomical missing tooth structure in the posterior mandibular tooth area is lowered to form an occlusion and aesthetics confirmation device. Then, tooth arrangement is performed according to the three-dimensional spatial position of the teeth. Finally, the jaw position guide plate is fabricated according to the data after tooth arrangement. S4: Preparation of fine impression and confirmation of jaw position and aesthetic relationship: The fine impressions of the maxilla and mandible are prepared through the jaw position guide plate obtained in S3, and the occlusal record data is obtained in the posterior tooth area after occlusion. S5: Preparation of complete denture: The edentulous jaw data of the complete denture is obtained by scanning the fine impression obtained in S4, and it is fitted with the occlusal record data to obtain the complete denture data, and it is fabricated by 3D printing or machining. In S2, the jaw position adjustment is carried out through the following steps: First, align the mental point position of the mandible with the midfacial line. When the mandibular angle point is at a 40 - 50° elevation, it is on the same horizontal line. The positions of the two condyles are symmetrical, and the mandible is centered. Then, confirm that the condyle position is located within the glenoid fossa. Then, adjust the jaw to the lateral view. Based on the orbital axis plane, adjust the position of the mandible until the angle formed by the mandibular plane angle and the orbital axis plane is 20 - 30°. Finally, adjust the vertical distance between the maxilla and mandible in the plane where the midfacial line is located to be 12 - 18 mm. In S3, a occlusal plane plate with an angle of 0 - 25° is used for tooth arrangement, and the three-dimensional spatial position of the teeth is designed according to the following formula: X = a + b + c; In the formula, X is the protrusive condylar path inclination, a is the angle of the occlusal plane plate, b is the cusp inclination, and d is the posterior tooth separation angle. In S4, the occlusal record data is obtained through the following steps: First, fix the silicone rubber through the fixing pins designed on the gingiva in the posterior mandibular tooth area of the jaw position guide plate. Then, occlude the maxillary and mandibular dentitions obtained after the fine impression, align the midlines of the upper and lower dentitions, and obtain the occlusal record data in the posterior tooth area.

2. The digital complete denture preparation method based on precise mandibular positioning according to claim 1, wherein, In S1, before performing CBCT and intraoral optical scans, fluid resin is adhered to the alveolar ridge mucosa of the patient to form a small vertebral shape.

3. The digital complete denture preparation method based on precise mandibular positioning according to claim 1, wherein, In S1, the patient's cranio-maxillofacial CBCT data is DICOM data, and the edentulous maxilla and mandible data are STL data.

4. The digital complete denture preparation method based on precise mandibular positioning according to claim 1, wherein, The preparation method of the jaw guide plate in S3 is to be manufactured by numerical control cutting or 3D printing.

5. A digital complete denture based on precise mandibular positioning, characterized in that, It is obtained by using the preparation method described in any one of claims 1-4.

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