AU2017101387A4

AU2017101387A4 - A method to develop a mouthguard for treatment of temporomandibular joint disorder

Info

Publication number: AU2017101387A4
Application number: AU2017101387A
Authority: AU
Inventors: Jamal Kashani
Original assignee: Kashani Jamal Dr
Current assignee: Kashani Jamal Dr
Priority date: 2017-10-17
Filing date: 2017-10-17
Publication date: 2017-11-16
Anticipated expiration: 2025-10-17

Abstract

A method that may be used to develop a customized mouthguard to treat temporomandibular joint disorder (TMJD). It particularly designs the mouthguard in a computer-aided design (CAD) software program based on three dimensional (3D) digital casts of the upper and lower jaws of the patient. The method includes an adjustable virtual articulator, which is used to place the lower jaw's cast in a correct position in relation to the model of patient's upper dentition. The CAD model of the mouthguard is developed in the CAD software program based on the patient's upper and lower dentition's models. The mouthguard is then manufactured using its CAD model. 3D digital casts of the upper and lower jaws Import 3D digital cast's files to a CAD software program Virtual articulator 0Adjust lower jaw's cast CAD model 6 to provide correct occlusion 'I Develop CAD model of the mouth guard 7 Manufacture the mouth guard 7 Fig. 1

Description

A METHOD TO DEVELOP A MOUTHGUARD FOR TREATMENT OF TEMPOROMANDIBULAR JOINT DISORDER

FIELD OF INVENTION

[001] The present invention relates to a method to develop a customized mouthguard that may be used for the treatment of temporomandibular joint disorder (TMJD). In particular, the present invention relates to a mouth stent that is designed based on the morphology of the patient mouth and mounted on the patient’s upper dentition while it touches lower dentition of the patient to push the lower jaw in its correct position.

BACKGROUND OF THE INVENTION

[002] The temporomandibular joint (TMJ) connects the upper jaw to the skull and allows the lower jaw to move up and down and side to side. The movements of the lower jaw are crucial for many functions such as talking and chewing. The TMJ does not work properly in TMJD, in which the lower jaw may be dislocated. It may cause tension headaches, pain in the jaw, ears, face or neck, and chewing problems.

SUMMARY OF THE INVENTION

[003] A number of mouthguards have been developed to readjust the lower jaw and put it in the correct position. In a conventional method of the TMJD mouthguard manufacturing, the lower and upper jaws’ plaster casts are used and the mouthguard is manufactured manually. However, as the medical practitioner, such as a medical doctor or a dentist who ordered mouthguard, is able to see the mouthguard only after final product fabrication, he has no opportunity to check the design of the mouthguard before manufacturing. Consequently, design errors that might be occurred due to misunderstanding and miscommunication between the medical practitioner and manufacturer, cannot be avoided. In addition, as the mouthguard is manufactured manually, the accuracy may be varied case by case and includes human errors as well. Therefore, the effectiveness of current TMJD mouthguards are limited, and there is a need for accurate, more controllable and cost-effective methods.

[004] The present invention aims to provide a mouthguard to treat TMJD by pushing lower jaw to its correct position. It is developed based on the patient’s upper and lower dentition, and the correct contact between lower and upper jaws’ teeth (occlusion). It also allows medical practitioners to monitor the process of design of the mouthguard at any stage for possible design change or correction before manufacturing.

[005] In the presented method, three dimensional (3D) digital casts of the upper and lower jaws of the patient are prepared. A 3D digital cast shows a person's dentition and surrounding structures of oral cavity such as gum. The 3D digital cast can be prepared by using lasers and digital scanning of the patient mouth, or 3D scanning of the cast of dentition, which may be prepared by taking a dental impression and mould casting. The 3D digital cast data of the lower and upper jaws are imported to a computer-aided design (CAD) software program such as, but not limited to, SolidWorks, CATIA, and Autocad, where individual CAD models of the lower and upper jaws’ casts are developed.

[006] The present invention also includes an adjustable virtual articulator, which is developed in a CAD software program. This virtual articulator facilitates placing CAD model of the lower jaw’s cast in a correct position in relation to the upper jaw’s cast model, where the models provide correct occlusion. The CAD models of the lower and upper jaws’ cast are assembled on the virtual articulator, in which the upper jaw’s cast model is fixed and cannot move along or rotate about any axes, but the lower jaw’s cast model has six degrees of freedom. The position of the lower jaw’s cast model can be changed along three perpendicular axes. Its orientation can also be changed through rotation about those perpendicular axes. Therefore, the lower jaw’s cast model can be moved and rotated in order to be adjusted to produce correct occlusion.

[007] The CAD model of the patient’s mouthguard is developed in the CAD software program, based on the CAD models of the lower and upper jaws’ casts when the correct contact between lower and upper jaws’ teeth is provided. The mouthguard’s CAD model is developed in a way that it fits properly on the CAD model of upper jaw’s cast. The CAD model of mouthguard also fits on the teeth surface of the CAD model of lower jaw’s cast. The CAD model of the mouthguard is then used for manufacturing the mouthguard, using methods such as rapid prototyping. The mouthguard is preferably fabricated from elastic materials or rigid materials or combination of rigid and elastic materials such as, but not limited to, a rigid material that is covered by an elastic material.

[008] An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 is a flowchart showing an overview of the process of developing CAD model and manufacturing of the mouthguard.

Fig. 2 is an upper front perspective view of the virtual articulator and assembled CAD models of the upper and lower jaws’ casts.

Fig. 3 shows a cross-sectional view of the cylindrical beam 2B, cylindrical beam 4A, and Part 3 including hollow cylinders 3A and 3C. The cylindrical holes inside the 3C and 3A are shown with Hole 3C and Hole 3A respectively.

Fig. 4 is an upper front perspective view of the virtual articulator that shows possible movements and rotation of the parts, in which part 2 can move along axis X1 (DX1) and rotate about axis X1 (RX1), part 3 can move along axis X2 (DX2) and rotate about axis X2 (RX2), and part 4 can move along axis X3 (DX3) and rotate about axis X3 (RX3).

Fig. 5 is a lower front perspective view of the virtual articulator, lower jaw cast model 6 and upper jaw cast model 5. Lower jaw cast model 6 and upper jaw cast model 5 are fixed on the plates 4B and 1C respectively.

Fig. 6 is a lower front perspective view of the jaws cast CAD models on the virtual articulator and developed CAD model of mouthguard 7.

Fig. 7 is an upper side perspective view of the mouthguard CAD model in case lower jaw needs to move forward (towards the face) to be placed in its correct position.

Fig. 8 is a lower rear perspective view of the mouthguard CAD model in case lower jaw needs to move backward (towards the neck) to be placed in its correct position.

DESCRIPTION OF EMBODIMENTS

[009] The purpose of this embodiment of the invention is to develop CAD model of mouthguard 7 and use it for fabrication. According to Fig. 1,3D digital casts of the upper and lower jaws are prepared and imported to a CAD software program, where the CAD models of upper jaw cast 5 and lower jaw cast 6 are developed. In the CAD software program, the lower jaw’s cast model 6 is adjusted to provide a correct occlusion by means of a virtual articulator which is shown in Fig. 2.

[0010] The virtual articulator consists of four individual components (Part 1, Part 2, Part 3 and Part 4).Part 1 consists of cylindrical beam 1A, arm 1B and plate 1C, in which plate 1C and beam 1A are firmly joined with arm 1B. Part 2 consists of arm 2A and cylindrical beam 2B, which are joined firmly together. Part 3 consists of hollow cylinder 3A, solid cube 3B, and hollow cylinder 3C, in which hollow cylinders 3A and 3C are firmly joined to cube 3B. Part 4 consists of cylindrical beam 4A and plate 4B, which are joined firmly together. According to Fig. 3, Hole 3A and beam 2B have the same axis (X2) that allows hollow cylinder 3A to move along axis X2 (DX2 directions), and also rotate about axis X2 (shown as RX2 in Fig. 4). Hole 3C and beam 4A have the same axis (X3). Therefore, beam 4A can move towards inside and outside hollow cylinder 3C (along axis X3), and also rotate about axis X3 (shown as RX3 in Fig. 4). Cylindrical beam 1A passes through two holes in arm 2A, in which beam 1A and holes in arm 2A have the same axis (axis X1 in Fig. 4). Therefore, arm 2A can rotate about axis X1 (shown as RX1 in Fig. 4) and move along axis X1 (shown as DX1 in Fig. 4).

[0011] As beam 4A and plate 4B are fixed together and create Part 4, movement and rotation of beam 4A result in movement and rotation of plate 4B. As a result, plate B can move along axis X3 (DX3 directions in Fig. 4) and rotate about axis X3 (RX3 directions in Fig. 4). Hollow cylinder 3A is firmly connected to the cylinder 4A via solid cube 3B, resulting in transferring movements of cylinder 3A along axis X2 and rotation of cylinder 3A about axis X2 to cylinder 3C. Beam 4A and cylinder 3C have no degree of freedom along axis X2 and about axis X2, consequently, beam 4A moves along and rotates about axis X2 by moving cylinder 3C along axis X2 and rotating cylinder 3C about axis X2. These provide an ability of movement along axis X2 and rotation about axis X2 to plate 4B. Neither beam 2B and cylinder 3A nor cylinder 3C and beam 4A have a degree of freedom along and about axis X1. Therefore rotations and movements of part 2, including arm 2A and beam 2B, about and along axis X1 are transferred to beam 4A and plate 4B.

[0012] Axes X1, X2, and X3 are perpendicular to each other and plate 4B can move along them as well as rotating around them. Therefore, the virtual articulator provides six degrees of freedom to the plate 4B. Upper jaw’s CAD model 5 is assembled on plate 1C, and lower jaw’s CAD model 6 is assembled on plate 4B (Fig. 5). Upper jaw’s CAD model 5 and plate 1C cannot move or rotate as a result of fixing part 1 in the virtual articulator. Since lower jaw’s cast model 6 is fixed on the plate 4B, it rotates and moves with the plate 4B. Consequently, virtual articulator provides six degrees of freedom to the lower jaw’s cast model 6, including movement along axes X1, X2 and X3, and rotation about axes X1, X2, and X3 for the lower jaw’s cast model 6.

[0013] Lower jaw’s CAD model 6 may be moved along axes X1, X2 and X3, and rotate about axes X1, X2, and X3 to be placed in the position that produces acceptable occlusion, or the position that the medical doctor prefers for the lower jaw. After placing lower jaw’s CAD model 6 in its correct position, the CAD model of the mouthguard 7 is developed based on the lower jaw’s CAD model 6 and upper jaw’s CAD model 5 (Fig. 6). The CAD model of the mouthguard 7 is used for manufacturing purposes. The additive manufacturing methods such as, but not limited to, 3D printing, selective laser melting (SLM), Selective laser sintering (SLS), Stereolithography (SLA) and Fused deposition modelling (FDM), and subtractive manufacturing methods , such as, but not limited to, computer numerical control (CNC) may be used to fabricate the mouthguard 7.

[0014] Surface SU (Fig. 7 and Fig. 8) fits on upper jaw’s CAD model 5’s teeth and gum surface. Surface SL (Fig. 7) fits on the lingual surface of the lower jaw’s teeth model (the teeth surface facing the tongue). When a patient puts the manufactured mouthguard in his mouth, surface SU mounts on the upper jaw’s teeth and/or gum surface, and surface SL acts as an obstacle and prevents lower jaw to move back to the incorrect position if the lower jaw needs to be moved forward (buccal direction). In case that lower jaw needs to be moved backward (lingual direction), surface SB (Fig. 8) fits on the buccal surface of the lower jaw’s teeth model (the tooth surface facing the lips).

Claims

1. A method of developing a customized mouthguard for temporomandibular joint disorder treatment, comprising: 3D digital casts of the upper and lower jaws of the patient, including patient’s upper and lower dentition. A CAD software program, which is used for developing CAD models A virtual articulator which is developed in a CAD software program A mouthguard that is designed in a CAD software program A manufacturing technique using CAD model

2. A mouthguard according to claim 1, wherein the mouthguard is in contact with the buccal or lingual surface of the lower jaw’s teeth.

3. A mouthguard according to claim 1, wherein the mouthguard is in contact with buccal or lingual surface of the lower jaw’s gum.

4. A mouthguard according to claim 1, wherein the mouthguard is made of either elastic, rigid materials or combination of elastic and rigid materials.

5. A mouthguard according to claim 1, wherein the mouthguard is solid or hollow or porous or wire meshes.

6. A mouthguard according to claim 1, wherein the mouthguard is used to move lower jaw transversally (from left to right and vice versa).

7. A CAD software program according to claim 1, wherein the CAD software can be any computer software including commercial and open source software packages.

8. A 3D digital cast of the patient’s jaw according to claim 1, wherein the 3D digital cast is developed by using lasers and digital scanning of the patient mouth.

9. A 3D digital cast of the patient’s jaw according to claim 1, wherein the 3D digital cast is developed by 3D scanning of the dental casts of the patient’s upper and lower jaws.

10. A 3D digital cast of the patient’s jaw according to claim 1, wherein the 3D digital cast is a point cloud file or mesh model or surface model or CAD model.

11. A 3D digital cast of the patient’s jaw according to claim 1, wherein the 3D digital cast is developed by 3D scanning of the dental impression of the patient’s upper or lower teeth.

12. A mouthguard according to claim 1, wherein the mouthguard can be used as a dental guard (occlusal splint) for bruxism treatment.

13. A virtual articulator according to claim 1, wherein the virtual articulator may be developed in the same CAD software program that the 3D digital casts of the upper and lower jaws of the patient are imported.

14. A virtual articulator according to claim 1, wherein the virtual articulator may be developed in a CAD software program and then is imported into the CAD software program that the 3D digital casts of the upper and lower jaws of the patient are imported.