System and method for manufacturing personalized silicone orthodontic appliance for children in the period of tooth replacement

Abstract

The present invention proposes a manufacturing system and method of personalized silicone braces for children in the edentulous period, the system includes a three-dimensional modeling module, a measurement and analysis module, a correction module and a 3D printing module for braces, the three-dimensional modeling module and the measurement and analysis module also include a tooth-bone-muscle registration module for registering and aligning the three-dimensional dental jaw model with the lateral film and the profile photo; the correction module includes an automatic tooth arrangement and construction module, an automatic jaw position simulation module and an automatic muscle constraint module. The present invention is based on the normal data of children's cephalometric measurement, abandons the subjective experience of doctors, uses computer three-dimensional aided design of jaw positioning, muscle environment and tooth induction position, and manufactures medical silicone braces by integrated 3D printing, which not only meets the requirements of personalized and efficient correction, but also meets the requirements of production cost control, and at the same time realizes the joint correction of teeth, muscles and jaws for children in the edentulous period, thereby achieving the purpose of functional remodeling and facial beauty.

Description

Technical Field

[0001] The invention belongs to the technical field of early correction of early malocclusion in children. Background Art

[0002] According to the epidemiological survey data of the Chinese Stomatological Association, the incidence of malocclusion during the period of children's growth and development can be as high as 71.21%. During this period, bad oral habits (including mouth breathing, abnormal swallowing, finger sucking and lower lip biting, etc.), tooth replacement disorders and dietary structure will lead to uneven tooth arrangement, abnormal occlusion and abnormal morphological position of the upper and lower jaws. Malocclusion during the period of children's tooth replacement not only reduces the oral chewing function and increases the gastrointestinal burden, but also seriously hinders the normal growth and development of the face, and then is ridiculed by people around and becomes inferior, which seriously affects physical and mental health. Timely intervention during the growth and development period of children blocks bad oral habits, establishes a normal perioral muscle environment, guides the orthopedic growth of the upper and lower jaws, and induces the shaping and arrangement of teeth, which can achieve good appearance and healthy oral function with half the effort. It has become a social consensus to let every child have a healthy and neat set of good teeth.

[0003] Traditional early orthodontic appliances mainly include bracketless invisible braces for correcting uneven teeth, myofunctional appliances for coordinating perioral muscles, and jaw orthotics for correcting the position of the upper and lower jaws. The appropriate tooth, jaw and muscle appliances are selected according to the different malocclusions of each child.

[0004] At present, the invisible braces for correcting teeth are a series of invisible braces obtained by scanning the child's dentition to generate a digital dental model, computer-aided design of the final position and movement steps of the teeth, and direct resin 3D printing of the dentition model of each step, and finally pressing and molding. The purpose of correction for children is not only to align their teeth, but more importantly to improve the beauty of their facial shape. Based on the principle of correction that gives priority to facial correction, especially for children in the growth and development period, the upper and lower jaws, muscles, and teeth may be remodeled. Therefore, in this golden period of development, facial management of jaw correction has become a common wish of doctors and parents of children. For children in the period of tooth replacement, on the one hand, the teeth have not been completely replaced, and on the other hand, simply aligning the teeth is far from enough due to the lack of facial and jaw data, without considering the position of the alveolar base bone, and thus without changing the facial appearance.

[0005] Traditional myofunctional appliances and mandibular orthoses are made by using the child's dental and maxillofacial models as a reference for the occlusal relationship in the mouth and are sent to a processing center for production. The effect of the treatment is directly related to the subjective design of the treating physician and the accumulated experience of the production technician.

[0006] In order to simplify the treatment, a commercial prefabricated appliance is currently used in clinical treatment for the problem of dental and jaw deformities in children and adolescents. The appliance presets an ideal position for teeth, jaws, and muscles. By wearing the prefabricated appliance, the teeth are induced to align, the jaw position is repositioned, and the muscle environment is coordinated. However, since each child's teeth, jaws, and muscles are different, the above-mentioned prefabricated appliance has problems such as uncomfortable wearing, unclear correction effect, and too long correction period. There is even a situation where the deformity of the prefabricated appliance worsens due to unclear diagnosis, and the condition gets worse with treatment.

[0007] Since the location, condition and severity of deformity of each child are different, it is unrealistic to use a prefabricated appliance to solve all problems; according to the current production process, clinical prefabricated early appliances are mostly made of elastic and comfortable medical silicone materials, which require mold making, injection molding and filling of the mold for mass production. This production process hinders personalized customization, because once full personalized customization is implemented, it is impossible to bridge the gap between personalized customization and traditional manufacturing methods for prototyping and mass production, resulting in extremely high production costs, which in turn limits the use of clinical corrections. Summary of the invention

[0008] In view of the defects of the prior art, the present invention proposes a manufacturing system of a personalized silicone appliance for children in the dentition replacement period. The system adopts the following technical solutions to achieve the goal:

[0009] A system for manufacturing braces for children in the dentition replacement period comprises a three-dimensional modeling module, a measurement and analysis module, a correction module and a 3D printing module for braces, wherein a tooth-bone-muscle registration module is further provided between the three-dimensional modeling module and the measurement and analysis module, for registering and superimposing a three-dimensional dental-jaw model with a lateral film and a profile photograph; the correction module comprises an automatic tooth arrangement and construction module, an automatic jaw position simulation module and an automatic muscle constraint module; the automatic tooth arrangement and construction module is used to automatically calculate a dental arch curve according to the transverse width and normal physiological curvature of the first molar, and to establish a normal overbite and occlusion relationship between the front and back teeth; the automatic jaw position simulation module is used to simulate the movement of the temporomandibular joint of the child, thereby coordinating the target positions of the upper and lower jaws, and establishing a normal position relationship of the upper and lower jaws in the anterior-posterior, vertical and lateral directions; the automatic muscle constraint module determines the edge of the braces according to the buffer design of the turning position of the floor of the mouth and the vestibule mucosa.

[0010] Furthermore, the correction module also includes: an incisor position setting module, which sets the final position of the upper and lower central incisors according to the maxillary central incisor distance and the mandibular central incisor angle, manually sets the lateral width position of the first molar according to the WALA ridge, the most protruding part of the buccal side of the mandibular alveolar bone, and then sends it to the automatic teeth arrangement module to determine the overlapping position of the incisors; a jaw position setting module, which sets the anteroposterior target positions of the upper and lower jaws according to the anterior-posterior indicator ANB angle of cephalometric measurement; sets the vertical target positions of the upper and lower jaws according to the vertical indicator FMA angle of cephalometric measurement; manually sets the lateral position of the mandible according to the midline of the lower dental arch; and sends it to the automatic jaw position simulation module to determine the three-dimensional positions of the upper and lower jaws; a screen position setting module, which sets the morphological structure of the upper and lower lip screens, cheek screens and tongue induction screens, and sends it to the automatic muscle constraint module to determine the extension boundary of the silicone appliance.

[0011] Furthermore, the dento-bone-muscle registration module includes: an adjustment module, used to adjust the profile photo to a translucent state, and to overlap the nose tip point and the prechin point on the photo with the nose tip point and the prechin point on the lateral skull film, until the profile photo completely overlaps with the depressed area of ​​the root of the nose on the lateral skull film; to overlap the three-dimensional dental jaw model with the maxillary central incisor tangent point and the maxillary first molar mesiobuccal cusp on the lateral skull film, until the three-dimensional dental jaw model and the mandibular central incisor tangent point on the lateral skull film completely overlap; a judgment module, checking whether the side image of the three-dimensional dental jaw model projected on the midsagittal plane overlaps with the image of the X-ray lateral film, if so, outputting the image to the measurement and analysis module, otherwise outputting it to the measurement and analysis module after passing through the correction module; a correction module, rotating the midsagittal plane left and right with the central axis of the dentition as the center, so that the side image overlaps with the image of the X-ray lateral film.

[0012] Furthermore, the measurement and analysis module is used to obtain the three-dimensional positions of the upper and lower jaws and the labiolingual positions of the upper and lower central incisors based on the measurement and analysis of the X-ray cephalogram; and the WALA ridge, the most protruding part of the buccal side of the mandibular alveolar bone, is used to determine the width position of the upper and lower dental arches.

[0013] Furthermore, the three-dimensional modeling module is used to scan the child's dentition and mucosa, establish a three-dimensional model of the soft and hard tissues in the child's mouth, and automatically divide the three-dimensional dental model into independent crown individuals, and set tooth feature landmarks.

[0014] Furthermore, it also includes a manual fine-tuning module for manually fine-tuning the position of the jaw in three dimensions, the labio-lingual position of the upper and lower anterior teeth, and the width curves of the upper and lower dental arches. It also includes a VTO analysis and prediction module, which simulates the change of soft tissue profile according to the final position of the upper and lower jaws and dental hard tissues set in cephalometric measurement, and then obtains the prediction of the profile photo and generates a before-and-after comparison animation.

[0015] The present invention further proposes a method for manufacturing a personalized silicone brace for children in the edentulous period, comprising a three-dimensional modeling step, a measurement and analysis step, a correction step, and a brace design and printing step. The three-dimensional modeling step and the measurement and analysis step also include a tooth-bone-muscle alignment step, which performs alignment and overlap of the three-dimensional dental jaw model with the lateral film and the profile photo; the correction step includes: an automatic tooth arrangement and construction step, which automatically calculates the dental arch curve based on the lateral width and normal physiological curvature of the first molar, and establishes the normal overbite and occlusion relationship of the anterior and posterior teeth; an automatic jaw position simulation step, which simulates the movement of the child's temporomandibular joint, thereby coordinating the target positions of the upper and lower jaws, and establishing the normal position relationship of the upper and lower jaws in the anterior-posterior, vertical and lateral directions; an automatic muscle constraint step, which determines the edge of the brace according to the buffer design of the turning position of the floor of the mouth and the vestibule mucosa.

[0016] Furthermore, the correction step also includes: an incisor position setting step, which sets the final position of the upper and lower central incisors according to the maxillary central incisor distance and the mandibular central incisor angle, manually sets the lateral width position of the first molar according to the WALA ridge, the most protruding part of the buccal side of the mandibular alveolar bone, and then determines the incisor overlapping position through an automatic tooth arrangement step; a jaw position setting step, which sets the anterior-posterior target position of the upper and lower jaws according to the anterior-posterior indicator ANB angle of cephalometric measurement; sets the vertical target position of the upper and lower jaws according to the mandibular plane angle FMA, a vertical indicator of cephalometric measurement; manually sets the lateral position of the mandible according to the midline of the lower dental arch; and determines the three-dimensional position of the upper and lower jaws through an automatic jaw position simulation step; a screen stop position setting step, which sets the morphological structure of the upper and lower lip stops, cheek stops and tongue induction stops, and determines the extension boundary of the silicone appliance through an automatic muscle constraint step.

[0017] Furthermore, in the mandibular position setting step: for children with maxillary protrusion and mandibular retraction with ANB greater than 5° in the anteroposterior misalignment, the mandible is designed to be advanced and the maxilla is retracted, and the ANB is manually fine-tuned to 2.5°-3.5°; for children with mandibular protrusion and maxillary retraction with ANB less than 3° in the anteroposterior misalignment, the maxilla is designed to be advanced and the mandible is retracted, and the ANB is manually fine-tuned to 3°-5°; for children with long face, high angle and shallow overbite and FMA greater than 35°, the mandible is designed to perform counterclockwise hinge movement; for children with short face, low angle and deep overbite and FMA less than 25°, the mandible is designed to perform clockwise hinge movement, so that the FMA returns to the normal value range, wherein ANB is the angle between the line connecting the nasion point and the upper alveolar seat point and the line connecting the nasion point and the lower alveolar seat point, and FMA is the angle between the orbitoauricular plane and the mandibular plane.

[0018] Compared with the prior art, the advantages and positive effects of the present invention are as follows: the present invention obtains the original three-dimensional dental and jaw model before orthodontic treatment, aligns the three-dimensional dental and jaw model with the lateral skull film and corrects it, then determines the three-dimensional target position of the jaw and dentition according to the normal range of child cephalometric measurement, sends the correction module, constructs the final position of the upper and lower jaws and teeth and the muscle constraint boundary, and finally generates the appliance through the appliance 3D printing module and directly performs silicone 3D printing. The present invention abandons the subjective experience of doctors based on the normal data of child cephalometric measurement, uses computer three-dimensional aided design of jaw positioning, muscle environment and tooth induction position, and manufactures medical silicone appliances by integrated 3D printing, which not only meets the requirements of personalized and efficient correction, but also meets the requirements of production cost control, and at the same time realizes the joint correction of teeth, muscles and jaws for children in the tooth replacement period, thereby achieving the purpose of functional remodeling and facial beauty. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a system structure block diagram of the present invention;

[0020] Figure 2 It is a picture obtained by registering and superimposing the three-dimensional dental jaw model with the lateral film and the profile photograph in the second tooth-bone-muscle registration step of the present invention;

[0021] Figure 3-1 It is a comparison diagram of the initial state and the designed state in the second automatic tooth arrangement and occlusal construction step (maxillary occlusal view) of the present invention;

[0022] Figure 3-2 It is a comparison diagram of the initial state and the designed state in the second automatic tooth arrangement and occlusal construction step (mandibular occlusal view) of the present invention;

[0023] Figure 4-1 It is a comparison diagram of the initial state and the designed state in the second automatic jaw position simulation step (front occlusal view) of the present invention;

[0024] Figure 4-2 It is a comparison diagram of the initial state and the designed state in the second automatic jaw position simulation step (side occlusal view) of the present invention;

[0025] Figure 5 It is a schematic diagram of the temporomandibular joint movement of a patient simulated by a simulated virtual jaw frame in the second automatic jaw position simulation step of the present invention;

[0026] Figure 6 It is a schematic diagram of determining the edge of the appliance in the second automatic muscle constraint step of the present invention;

[0027] Figure 7 This is a schematic diagram of a 3D printed silicone orthodontic appliance after the orthodontic appliance design is completed according to the second embodiment of the present invention. DETAILED DESCRIPTION

[0028] The applicant found that most children's malocclusion involves abnormal position of the upper and lower jaws, uncoordinated perioral muscles and irregular tooth arrangement. Only by correcting the teeth, muscles and jaws together can the purpose of functional remodeling and facial beauty be achieved. Based on the above, the present invention proposes a fully automatic tooth-bone-muscle design system guided by teeth, jaws and normal cephalometric indicators. In order to facilitate the understanding of the present invention, the present invention is further described below in conjunction with the embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

[0029] Example 1, reference Figure 1 This embodiment provides a system for manufacturing a personalized silicone appliance for children in the edentulous period, including:

[0030] The 3D modeling module is used to perform 3D reconstruction of the child's dentition and mucosa, automatically divide the teeth into independent crown individuals, and set tooth feature landmarks. This application not only scans and reconstructs the hard tissue of the dentition, but also scans and reconstructs the soft tissue of the oral mucosa, thereby realizing the design of the muscle constraint part of the early orthodontic appliance.

[0031] The tooth-bone-muscle registration module is used for the registration, overlap and correction of the three-dimensional dental-mandibular model with the lateral film and the profile photograph. This application takes the aesthetic appearance of the profile as an important criterion for correcting the position of the jaw teeth. The module includes: an adjustment module, which is used to adjust the profile photograph to a translucent state, and to overlap the nose tip point and the prechin point on the photo with the nose tip point and the prechin point on the lateral film, until the profile photograph completely overlaps with the nasal root depression area on the lateral skull film; overlap the maxillary central incisor tangent point and the maxillary first molar mesiobuccal cusp on the three-dimensional dental-mandibular model and the lateral skull film, until the mandibular central incisor tangent point on the three-dimensional dental-mandibular model and the lateral skull film completely overlaps. The judgment module checks whether the side image of the three-dimensional dental model projected on the median sagittal plane coincides with the image of the X-ray lateral film. If so, the image is output to the measurement and analysis module; otherwise, it is output to the measurement and analysis module after passing through the correction module; the correction module rotates the median sagittal plane left and right with the central axis of the dentition as the center, so that the side image coincides with the image of the X-ray lateral film.

[0032] Measurement and analysis module: This module uses the three-dimensional directional indicators in cephalometric measurement for tooth and jaw target positioning. It is mainly used to obtain the three-dimensional position of the upper and lower jaws and the labiolingual position of the upper and lower central incisors based on the measurement and analysis of the X-ray cephalometric film; the WALA ridge, the most protruding part of the buccal side of the mandibular alveolar bone, is used to determine the width of the upper and lower dental arches. The WALA ridge is a protruding ridge located at the junction of the free gingiva and attached gingiva of the mandibular alveolar. When observed from the occlusal direction, it is the most prominent part of the buccal alveolar bone.

[0033] The automatic tooth arrangement and construction module is used to automatically calculate the target position of the upper and lower incisors according to the final position of the upper and lower central incisors by Boolean calculation, automatically calculate the dental arch curve according to the transverse width and normal physiological curvature of the first molar, and establish the normal overbite and occlusion relationship of the front and back teeth. Traditional tooth arrangement is to align the teeth according to the normal standard. This application determines the overlapping position of the upper and lower incisors through Boolean calculation, and designs a wide space-occupying alveolus in the posterior teeth to increase the width of the dental arch, maintain the gap between the replacement teeth after the deciduous teeth fall out, and guide the smooth eruption and construction of the successor permanent teeth.

[0034] Incisor position setting module is used to set the automatic calculation of the upper dental arch curve and align the teeth.

[0035] The automatic jaw position simulation module uses a computer virtual jaw frame to coordinate the target position of the upper and lower jaws, and establish the normal position relationship of the upper and lower jaws in the anterior-posterior, vertical and lateral directions. This application simulates the movement of the child's temporomandibular joint by simulating a virtual jaw frame to create the normal position relationship of the upper and lower jaws in the anterior-posterior, vertical and lateral directions, without relying on the subjective experience of clinicians and production technicians to determine.

[0036] The jaw position setting module is used to manually set the final position of the upper and lower jaws, and send it to the automatic jaw position simulation module for automatic calculation of the jaw position relationship to determine the three-dimensional position of the upper and lower jaws.

[0037] The automatic muscle constraint module is used to automatically buffer and design the edge of the appliance according to the turning position of the floor of the mouth and the vestibular groove mucosa, so as to achieve the effect of coordination of the perioral muscle environment, no mucosal irritation, and comfortable wearing. This application can design the edge thickness of the appliance according to the position of the mucosal muscles of the child, avoiding the adjustment and modification in actual clinical wearing.

[0038] The screen position setting module manually sets the edge positions of the upper and lower lip screens, cheek screens, and tongue induction screens according to the actual perioral muscle imbalance of the child, and sends them to the automatic muscle constraint module for automatic calculation of the thickness boundary of the appliance to determine the extension boundary of the silicone appliance. This application designs a personalized lip screen and cheek screen structure based on the actual perioral muscle imbalance of the child, thereby achieving the maximum muscle reconstruction effect.

[0039] The manual fine-tuning module is used to manually fine-tune the three-dimensional position of the jaw, the labio-lingual position of the upper and lower front teeth, the width curve of the upper and lower dental arches, and to make fine adjustments to the boundary position of the silicone appliance.

[0040] The VTO (Visual Treatment Objective, VTO) analysis and prediction module is used to send the final positions of the upper and lower incisors and the upper and lower jaws in the three-dimensional dental model to the automatic tooth arrangement module and the automatic jaw position simulation module. While automatically designing the final positions of the upper and lower jaws and dentition, it can simulate the cephalometric soft tissue profile changes, and then obtain the prediction of the profile photo, and generate a before-and-after animation effect. This module converts the three-dimensional directional changes of the patient's jaw and teeth into changes in facial soft tissues, providing a good tool for prediction of treatment effects and communication between doctors and patients.

[0041] The orthodontic appliance 3D printing module uses a reverse engineering algorithm to design the silicone pad wrapping connection of the orthodontic appliance on the positioned upper and lower jaws and dentition, and automatically designs the edge of the orthodontic appliance according to the turning position of the floor of the mouth and the vestibular groove mucosa. After the orthodontic appliance design is completed, it can be directly 3D printed using silicone or materials with silicone-like properties, or a high-temperature resistant silicone mold can be 3D printed, and then the silicone orthodontic appliance can be made by injection molding.

[0042] Embodiment 2: This embodiment provides a method for manufacturing a personalized silicone appliance for children in the edentulous period, comprising:

[0043] Step 1: 3D Modeling

[0044] The child's dentition and mucosa are scanned using intraoral scanning equipment (intraoral scanner or plaster model scanner), and three-dimensional reconstruction is performed using computer three-dimensional image processing software to establish a three-dimensional model of the child's soft and hard tissues in the mouth. The dentition model is automatically divided into independent crown individuals, and tooth characteristic landmarks are set.

[0045] Step 2: Measurement and Analysis

[0046] The main task is to complete the measurement and analysis of X-ray lateral skull films to obtain the three-dimensional positions of the upper and lower jaws, and the labiolingual positions of the upper and lower central incisors; the WALA ridge, the most protruding part of the buccal side of the mandibular alveolar bone, is used to determine the width of the upper and lower dental arches.

[0047] Step 3: Tooth-bone-muscle registration

[0048] Place the lateral skull film on the median sagittal plane of the 3D dental model. The median sagittal plane should coincide with the plane of the facial midline. The purpose is to align the scale of the lateral skull film, the profile photo, and the scale of the 3D dental model. The specific steps are as follows:

[0049] Adjust the profile photo to a semi-transparent state, overlap the nose tip point and the chin point in the photo with the nose tip point and the chin point in the lateral film, and then manually fine-tune it so that the profile photo completely overlaps with the sunken area of ​​the root of the nose in the lateral skull film.

[0050] The incision points of the maxillary central incisor and the mesiobuccal cusp of the maxillary first molar on the three-dimensional jaw model and the lateral skull film were overlapped, and then manual fine-tuning was performed to make the incision points of the mandibular central incisor on the three-dimensional jaw model and the lateral skull film completely overlapped.

[0051] Finally, check whether the lateral image of the three-dimensional dental model projected on the midsagittal plane coincides with the image of the lateral X-ray film. If there is a deviation, rotate the midsagittal plane left and right with the central axis of the dentition as the center to make the two images coincide.

[0052] like Figure 2 As shown, after the patient's soft tissue profile photograph, mandibular lateral radiograph and three-dimensional dental model are aligned and overlapped together, the maxillary central incisor with labial inclination in the figure is uprighted to the normal position according to the normal cephalometric data. The changes in soft tissue profile can then be automatically simulated in the computer software for VTO analysis.

[0053] Step 4: Automatic tooth arrangement and matching

[0054] The incisor overlap target position is automatically calculated by Boolean calculation based on the final position of the maxillary and mandibular central incisors. The dental arch curve is automatically calculated based on the transverse width and normal physiological curvature of the first molar, and the normal overbite, coverage and occlusion relationship of the anterior and posterior teeth are established. Figure 3-1 to Figure 3-2 The left part in the middle is the initial state before tooth arrangement, and the right part is the designed state after tooth arrangement.

[0055] Step 5: Incisor position setting

[0056] The final positions of the upper and lower central incisors are set according to the maxillary central incisor distance and the mandibular central incisor angle, and the transverse width position of the first molar is set according to the WALA ridge, the most protruding part of the buccal side of the mandibular alveolar bone. Then, the automatic tooth arrangement and construction steps are used to automatically calculate the incisor overlapping position and dental arch curve to level and align the teeth.

[0057] The maxillary central incisor distance refers to the vertical distance from the maxillary central incisor point to the line connecting NA (the nasal root point N is the most anterior point of the nasofrontal suture, and the upper alveolar seat point A is the most concave point of the bone between the anterior nasal spine and the upper alveolar margin point), and the normal distance is 4mm. The maxillary central incisor position with a maxillary central incisor distance of 4mm is manually set to achieve the maxillary central incisor standing upright on the upper alveolar base bone, neither lip tilted nor lingual tilted, thereby achieving the ideal position of the upper lip and restoring the normal face shape.

[0058] The mandibular central incisor angle refers to the angle between the long axis of the mandibular central incisor and the mandibular plane. It is generally believed that the mandibular central incisor should stand upright on the alveolar base bone, that is, the mandibular central incisor angle is a right angle of 90°. The mandibular central incisor position with a right angle is manually set to achieve the mandibular central incisor standing upright on the alveolar base bone, neither labially nor lingually inclined, thereby achieving the ideal position of the lower lip and restoring the normal facial shape and depth of the chin-labial groove. After the labio-lingual position of the upper and lower mandibular central incisors is determined, the upper and lower teeth are aligned from the midline of the upper and lower dentition to the distal according to the upper and lower dental arch curves through the automatic tooth arrangement and construction steps, and normal overbite and coverage of the anterior and posterior teeth are established.

[0059] The WALA ridge is the most prominent ridge on the soft tissue band at the junction of the mandibular attached gingiva and the alveolar mucosa, roughly located at the mucogingival junction. In the ideal normal dentition, the distance from the midpoint of the long axis of the mandibular clinical crown to the WALA ridge ranges from 0.1mm for the anterior teeth to 2.2mm for the posterior teeth, especially the distance from the midpoint of the long axis of the mandibular first molar to the WALA ridge is 2mm.

[0060] For children with deep overjet of posterior teeth due to excessive maxillary width and narrow mandible in transverse width imbalance, in order to achieve better correction effect and prevent recurrence, the maxillary arch width can be narrowed and the mandibular arch width can be increased, so that the overjet relationship of the upper and lower posterior teeth is opposite, thereby establishing a normal transverse width position relationship of the upper and lower jaws. For children with cross-overjet of posterior teeth due to excessive maxillary width and narrow mandible in transverse width imbalance, in order to achieve better correction effect and prevent recurrence, the mandibular arch width can be narrowed and the maxillary arch width can be increased, so that the overjet relationship of the upper and lower posterior teeth is deep overjet 2-3mm, thereby establishing a normal transverse width position relationship of the upper and lower jaws.

[0061] Step 6: Automatic jaw position simulation

[0062] refer to Figure 4-1 , Figure 4-2 and Figure 5 , a computer-designed simulated virtual jaw frame is used to simulate the patient's temporomandibular joint movement, thereby coordinating the target positions of the maxillary and mandibular bones and establishing the normal position relationship of the maxillary and mandibular bones in the anterior-posterior, vertical and lateral directions. Figure 4-1 to Figure 4-2 The left part in the middle is the initial jaw position state diagram, and the right part is the final jaw position state diagram.

[0063] Step 7: Jaw position setting

[0064] The anterior-posterior target positions of the maxillary and mandibular bones are manually set according to the anteroposterior index ANB angle of cephalometric measurement; the vertical target positions of the maxillary and mandibular bones are manually set according to the vertical index FMA angle of cephalometric measurement; the lateral position of the mandible is manually set according to the midline of the lower dental arch; and then the jaw position relationship is automatically calculated through the automatic jaw position simulation step to determine the three-dimensional positions of the maxillary and mandibular bones.

[0065] The ANB angle refers to the angle between the line connecting the nasion point and the upper alveolar seat and the line connecting the nasion point and the lower alveolar seat. It is mainly used to evaluate the anterior-posterior position relationship of the maxilla and mandible relative to the skull base. The FMA angle refers to the angle between the orbitoauricular plane and the mandibular plane. It is used to evaluate the vertical position relationship of the mandible relative to the orbitoauricular plane.

[0066] For children with maxillary protrusion (SNA angle greater than 85°) and mandibular retraction (SNB angle less than 75°) with ANB greater than 5°, the maxilla is pushed back and the mandible is guided forward to make the ANB angle (4.7±1.4)°. In order to achieve better correction effect and prevent recurrence, the ANB is fine-tuned to about 2.5°-3.5°, so as to establish a normal anteroposterior position relationship between the maxilla and mandible.

[0067] For children with overbite who have mandibular protrusion (SNB angle greater than 80°) and maxillary retraction (SNA angle less than 79°) with ANB less than 3°, the maxilla is advanced and the mandible is retracted to make the SNA (4.7±1.4)°. In order to achieve better correction effect and prevent recurrence, the ANB angle is fine-tuned to 3°-5°, so as to establish the normal anteroposterior position relationship between the maxilla and mandible.

[0068] For children with long face, high angle and shallow overbite whose mandibular plane angle (FMA) is greater than 35°, the mandible is designed to rotate counterclockwise in the virtual jaw frame of the computer, so that the mandibular plane angle (FMA) returns to the normal range and the vertical distance of the face reaches normal. After the mandible is designed to rotate counterclockwise, the gap in the posterior tooth area increases, so the thickness of the posterior occlusal pad of the orthodontic appliance increases, thereby lowering the posterior teeth. The mandible rotates counterclockwise, reducing the height of the lower third of the face and deepening the overbite of the anterior teeth.

[0069] For children with short faces, low angles and deep overbites whose mandibular plane angle (FMA) is less than 25°, the mandible is designed to rotate clockwise in the virtual jaw frame on the computer, so that the mandibular plane angle (FMA) returns to the normal range and the vertical distance of the face reaches normal. After the mandible is designed to rotate clockwise by the computer, the gap between the upper and lower posterior teeth is reduced and the gap between the anterior teeth is increased. Therefore, the thickness of the posterior occlusal pad is reduced and the thickness of the anterior occlusal pad is increased, thereby raising the posterior teeth and lowering the anterior teeth, thereby opening the overbite. The mandible rotates clockwise to increase the height of the lower third of the face.

[0070] After the original oral scan data was reconstructed by computer three-dimensional reconstruction, the consistency between the midline of the dental arch and the midline of the face was used as an indicator to evaluate the lateral deviation of the mandible. The dental deviation of the midline of the mandibular central incisor was first eliminated manually, and then the midline of the mandibular incisor was manually adjusted to be consistent with the midline of the face to correct the jaw relationship and determine the lateral position of the mandible.

[0071] Step 8: Automatic muscle constraints

[0072] like Figure 6 As shown in the figure, the edge of the appliance is designed with an automatic buffer of 2mm based on the turning point of the floor of mouth and vestibule mucosa, so as to achieve the effect of coordination of the perioral muscle environment, no mucosal irritation and comfortable wearing.

[0073] Step 9: Screen position setting

[0074] The morphological structures of the upper and lower lip guards, cheek guards and tongue induction guards were manually set, and the thickness boundary of the appliance was automatically calculated through the automatic muscle constraint step to determine the extension boundary of the silicone appliance.

[0075] When children with lower lip biting and abnormal swallowing habits have tension in the lower lip and mental muscles, and excessive tension, which leads to lingual crowding of the lower front teeth and even passive retraction of the mandible, in this case, the height of the lower lip stop is extended and thickened according to the depth of the mandibular vestibule groove and the turning point of the lower lip mucosa, and a teardrop-shaped protrusion is designed on its surface. This can isolate the mentalis muscle and massage and relax the lower lip.

[0076] For patients with crossbite due to insufficient development of the maxillary anterior alveolar teeth, extending the height of the upper lip stop and thickening the thickness of the upper lip stop can be set according to the depth of the maxillary vestibule groove and the turning point of the upper lip mucosa, which can stimulate and promote the development of the anterior part of the maxillary alveolar teeth to correct the crossbite.

[0077] Children with mouth breathing and abnormal swallowing will have a low tongue position, and the buccal muscles are too strong, causing the upper dental arch to be narrow and the mandible to be passively retracted. The depth of the tongue induction screen is set according to the depth of the floor of the mouth mucosa, and the tongue frenulum is tilted and thickened toward the floor of the mouth. At the same time, the height of the upper edge of the tongue guard is lowered, and the tongue is lifted up to the palatal side of the upper dentition, thereby playing the role of the tongue muscle expanding the upper dentition. For children with a long-term low tongue position and a stubborn tongue position, a tongue protrusion is designed symmetrically on the surface of the tongue induction screen to stimulate the tongue to be lifted high.

[0078] For children with long faces and high angles, whose facial buccal muscles are tense and lead to narrow upper and lower dental arches, the depth and thickness of the buccal screens on both sides can be set according to the anatomical depth of the vestibule groove in the mouth. This can effectively isolate the pressure of excessive buccal muscles, stimulate the upper and lower dental arches to develop and expand outward, and at the same time, better expand the arches under the action of the inner tongue muscles.

[0079] This step is based on the disorder of the child's perioral muscle environment. By setting the height and thickness of the upper and lower lip guards and cheek screens and the depth and angle of the tongue induction screen, it breaks the bad mouth breathing and abnormal swallowing habits, corrects the disorder of the lips, tongue, cheeks, chin and other muscles around the mouth, reshapes the normal perioral muscle environment, and promotes the maximum autonomous growth of the upper and lower jaws and dentition.

[0080] Step 10: Manual fine-tuning

[0081] Manually fine-tune the three-dimensional position of the jaw, the labio-lingual position of the upper and lower front teeth, the width curve of the upper and lower dental arches, and make fine adjustments to the boundary position of the silicone appliance.

[0082] Step 11: VTO analysis and forecast

[0083] After the three-dimensional dental model is registered and corrected with the lateral film, the final positions of the maxillary and mandibular bones and dentition are automatically designed, and the VTO profile contour of the soft tissue is calculated and simulated according to the hard tissue changes of the jaw and teeth in the cephalometric measurement. After the profile contour of the soft tissue on the lateral film is registered with the profile photograph, the postoperative changes in the child's profile can be predicted and an animation demonstration can be generated for efficacy prediction and doctor-patient communication.

[0084] This step mainly collects a large number of lateral skull radiographs and profile photos before and after treatment and performs fusion registration. Through big data analysis, the soft tissue upper and lower lip positions corresponding to different labio-lingual positions of the upper and lower central incisors, the changes in soft tissue profile protrusion corresponding to different anterior-posterior positions of the upper and lower jaws, and the lower third height of the soft tissue surface corresponding to different vertical positions of the upper and lower jaws are obtained. In this way, the upper and lower central incisor positions and the anterior-posterior and vertical positions of the upper and lower jaws can be set according to the normal values ​​of cephalometric measurement before correction, and then the soft tissue profile of the patient after the correction is predicted based on the correspondence between the hard tissues of the teeth and jaws and the soft tissue profile.

[0085] In specific applications, cephalometric analysis is performed on the lateral skull radiographs of a large number of cases before and after treatment. First, mark the landmarks of the maxillary and mandibular bones and teeth of each patient, including: sella turcica point, nasal root point, orbital point, anterior nasal spine and maxillary central incisor point, etc. For example, the orbital point is the lowest point of the inferior orbital margin, and the midpoint between the two orbital points is usually taken. Secondly, mark the soft tissue landmarks, including: forehead point, soft tissue nasal root point, nasal protrusion point, columella point and upper lip protrusion point, etc. For example, the soft tissue nasal root point is taken, and the corresponding nasal root point of the soft tissue profile is taken. Then, the one-to-one correspondence between the hard tissue landmarks and soft tissue landmarks of the maxillary and mandibular bones and teeth is confirmed through computer big data artificial intelligence learning, and then the one-to-one correspondence between the position of the teeth and jaws and the soft tissue profile is obtained.

[0086] Step 12: Print the appliance design

[0087] The silicone pad of the appliance is designed on the positioned upper and lower jaws and dentition through the reverse inversion algorithm, and the edge of the appliance is automatically designed according to the turning position of the floor of the mouth and the vestibular sulcus mucosa. After the appliance design is completed, silicone or materials with silicone-like properties are directly used for 3D printing, or high-temperature resistant silicone molds are 3D printed, and then silicone appliances are made by injection molding. Figure 7 shown.

[0088] The present invention uses computer-aided three-dimensional design to customize the jaw positioning, muscle environment and tooth induced position based on the normal cephalometric data of children, which not only meets the requirements of joint tooth-bone-muscle correction, but also meets the requirements of personalized and efficient treatment. It is elastic and comfortable, and matches safely. Clinical trials have shown that the compliance of children in wearing the device has been increased, the correction effect has been improved by 30%, and the treatment course can be shortened by nearly one-third.

[0089] In addition, the production process of traditional finished silicone braces requires the manufacture of metal molds first, followed by injection molding and filling of the metal molds for mass production. However, clinical efficient correction requires completely personalized silicone braces. For example, according to traditional processes, each brace requires a metal mold. The present invention uses a computer to design the braces in a personalized way, and then directly uses silicone or materials with silicone-like properties for 3D printing, or 3D prints high-temperature resistant silicone molds, and then manufactures silicone braces by injection molding. This not only meets the personalized design of different individuals, but also saves the process of making metal molds, reducing the cost to nearly one percent of the original process, making personalized silicone braces truly clinically usable.

[0090] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A manufacturing system for personalized silicone braces for children in the edentulous period, comprising a three-dimensional modeling module, a measurement and analysis module, a correction module and a braces 3D printing module, characterized in that: The measurement and analysis module is used to obtain the three-dimensional positions of the upper and lower jaws and the labiolingual positions of the upper and lower central incisors based on the measurement and analysis of the X-ray cephalogram; the WALA ridge, the most protruding part of the buccal side of the mandibular alveolar bone, is used to determine the width position of the upper and lower dental arches; The three-dimensional modeling module is used to scan the dentition and mucosa of the child, establish a three-dimensional jaw model of the soft and hard tissues in the child's mouth, and automatically divide the three-dimensional jaw model into independent crown individuals, and set tooth feature landmarks; A tooth-bone-muscle registration module is also included between the three-dimensional modeling module and the measurement and analysis module, which is used to perform registration and overlap between the three-dimensional dental and jaw models and the lateral film and profile photos; The correction module includes an automatic tooth arrangement module, an automatic jaw position simulation module and an automatic muscle restraint module; The automatic tooth arrangement and occlusion module is used to automatically calculate the dental arch curve according to the transverse width and normal physiological curvature of the first molar, and to establish normal overbite, coverage and occlusion relationship of the front and rear teeth; The automatic jaw position simulation module is used to simulate the temporomandibular joint movement of the child, thereby coordinating the target positions of the upper and lower jaws, and establishing the normal position relationship of the upper and lower jaws in the anterior-posterior, vertical and lateral directions; The automatic muscle restraint module determines the edge of the orthodontic appliance according to the buffer design of the turning position of the floor of mouth and the vestibular groove mucosa.

2. The manufacturing system of personalized silicone orthodontic appliances for children in the dentition period according to claim 1 is characterized in that: The correction module also includes: Incisor position setting module, which sets the final position of the upper and lower central incisors according to the maxillary central incisor distance and the mandibular central incisor angle, manually sets the transverse width position of the first molar according to the WALA ridge, the most protruding part of the buccal alveolar bone of the mandible, and then sends it to the automatic tooth arrangement module to determine the incisor overlap position; The jaw position setting module sets the anteroposterior target positions of the maxillary and mandibular bones according to the ANB angle, an anteroposterior index of cephalometric measurement; sets the vertical target positions of the maxillary and mandibular bones according to the FMA angle, an vertical index of cephalometric measurement; manually sets the lateral position of the mandibular bones according to the midline of the lower dental arch; and sends it to the automatic jaw position simulation module to determine the three-dimensional positions of the maxillary and mandibular bones; the ANB angle is the angle between the line connecting the nasion point and the upper alveolar seat point and the line connecting the nasion point and the lower alveolar seat point, and the FMA angle is the angle between the orbitoauricular plane and the mandibular plane; The screen stop position setting module sets the morphological structure of the upper and lower lip stops, cheek screens and tongue induction screens, and sends them to the automatic muscle constraint module to determine the extension boundary of the silicone appliance.

3. The manufacturing system of personalized silicone orthodontic appliances for children in the dentition period according to claim 1 is characterized in that: The tooth-bone-muscle registration module comprises: The adjustment module is used to adjust the profile photo to a semi-transparent state, and to overlap the nose tip point and the chin prepoint on the photo with the nose tip point and the chin prepoint on the lateral skull film, until the profile photo and the nasal root depression area on the lateral skull film are completely overlapped; overlap the maxillary central incisor incision point and the maxillary first molar mesiobuccal cusp on the three-dimensional dental jaw model and the lateral skull film, until the mandibular central incisor incision point on the three-dimensional dental jaw model and the lateral skull film are completely overlapped; The judgment module checks whether the side image of the three-dimensional dental model projected on the midsagittal plane coincides with the image of the X-ray lateral film. If so, the side image is output to the measurement and analysis module. Otherwise, it is output to the measurement and analysis module after passing through the correction module. The correction module rotates the mid-sagittal plane left and right with the central axis of the dentition as the center, so that the side image coincides with the image of the X-ray lateral film.

4. The manufacturing system of personalized silicone orthodontic appliances for children in the dentition period according to claim 1 is characterized in that: It also includes a manual fine-tuning module for manually fine-tuning the position of the jaw in three dimensions, the labio-lingual position of the upper and lower front teeth, and the width curves of the upper and lower dental arches.

5. The manufacturing system of personalized silicone orthodontic appliances for children in the dentition period according to claim 1, characterized in that: It also includes a VTO analysis and prediction module, which simulates the changes in soft tissue profile according to the final positions of the upper and lower jaws and dental hard tissues set in cephalometric measurement, and then obtains a prediction of the profile photo and generates a before-and-after animation.

6. A method for manufacturing a personalized silicone brace for children in the dentition replacement period, comprising a three-dimensional modeling step, a measurement and analysis step, a correction step, and a brace design and printing step, characterized in that: The three-dimensional modeling step comprises: The child's dentition and mucosa were scanned using intraoral scanning equipment, and three-dimensional reconstruction was performed using computer three-dimensional image processing software to establish a three-dimensional jaw model of the child's soft and hard tissues in the mouth. The three-dimensional jaw model was automatically divided into independent crown individuals, and tooth characteristic landmarks were set; The measurement and analysis steps include: The main task is to measure and analyze the lateral X-ray cephalogram to obtain the three-dimensional position of the upper and lower jaws, and the labiolingual position of the upper and lower central incisors; the WALA ridge, the most prominent part of the buccal alveolar bone of the mandible, is used to determine the width of the upper and lower dental arches; The three-dimensional modeling step and the measurement and analysis step also include a tooth-bone-muscle registration step, which is to register and overlap the three-dimensional dental jaw model with the lateral film and the profile photo; The correction steps include: Automatic tooth arrangement and occlusion step, which automatically calculates the dental arch curve based on the transverse width and normal physiological curvature of the first molar, and establishes normal overbite, coverage and occlusion relationship of the front and rear teeth; Automatic jaw position simulation step, which simulates the movement of the child's temporomandibular joint, thereby coordinating the target positions of the maxillary and mandibular bones and establishing the normal positional relationship of the maxillary and mandibular bones in the anterior-posterior, vertical and lateral directions; An automatic muscle constraint step that determines the edge of the appliance based on a buffered design of the mucosal transition between the floor of mouth and the vestibular groove.

7. The method for manufacturing a personalized silicone appliance for children in the dentition replacement period according to claim 6, characterized in that: The correction step also includes: Incisor position setting step, in which the final positions of the upper and lower central incisors are set according to the maxillary central incisor distance and the mandibular central incisor angle, the transverse width position of the first molar is manually set according to the WALA ridge, the most protruding part of the buccal alveolar bone of the mandible, and then the incisor overlap position is determined through the automatic tooth arrangement step; The mandibular position setting step sets the anteroposterior target positions of the maxillary and mandibular bones according to the anteroposterior index ANB angle of cephalometric measurement; sets the vertical target positions of the maxillary and mandibular bones according to the mandibular plane angle FMA of the vertical index of cephalometric measurement; manually sets the lateral position of the mandibular bones according to the midline of the lower dental arch; and determines the three-dimensional positions of the maxillary and mandibular bones through the automatic jaw position simulation step; the ANB angle is the angle between the line connecting the nasion point and the upper alveolar seat point and the line connecting the nasion point and the lower alveolar seat point, and the FMA angle is the angle between the orbitoauricular plane and the mandibular plane; The step of setting the screen stop position sets the morphological structure of the upper and lower lip stops, cheek stops and tongue induction screen, and determines the extension boundary of the silicone appliance through the automatic muscle constraint step.

8. The method for manufacturing a personalized silicone appliance for children in the dentition replacement period according to claim 7, characterized in that: In the jaw position setting step: For children with overbite and maxillary protrusion and mandibular retraction with an anteroposterior misalignment and ANB greater than 5°, the mandible is advanced and the maxilla is retracted, and the ANB is manually fine-tuned to 2.5°-3.5°; for children with overbite and mandibular protrusion and maxillary retraction with an anteroposterior misalignment and ANB less than 3°, the maxilla is advanced and the mandibular is retracted, and the ANB is manually fine-tuned to 3°-5°; for children with long face, high angle and shallow overbite and FMA greater than 35°, the mandible is designed to perform counterclockwise hinge movement; for children with short face, low angle and deep overbite and FMA less than 25°, the mandible is designed to perform clockwise hinge movement to restore the FMA to the normal range.

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