A modern approach to modeling eccentric mandibular movements and evaluating the stomatognathic system

Relevance. Currently, temporomandibular disorders (TMD) are highly prevalent. During the initial dental consultation and examination, special attention should be given to the diagnosis of TMD, as complications may arise following prosthetic treatment, particularly after extensive procedures, which may manifest as newly emerging or previously undiagnosed TMD disorders. The implementation of modern digital technologies enhances the accuracy and effectiveness of TMD diagnostics and treatment, ensuring compliance with established protocols, including the use of occlusal stabilization appliances (OSA).

Objective. To assess the effectiveness of a modern digital treatment protocol for designing an occlusal stabilization appliance, followed by temporary fixed dental restorations, in the treatment of patients with TMD involving both joint and myofascial dysfunction, with functional diagnostic monitoring.

Materials and methods. A clinical dental examination was performed on 78 individuals. Based on inclusion and exclusion criteria, 20 individuals diagnosed with TMD were assigned to the main group, while 20 individuals without TMD were included in the control group. Participants in the main group underwent cone-beam computed tomography (CBCT) and magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ). Both groups underwent electrognathographic recording (EGG) and surface electromyography (sEMG) using a functional diagnostic system. Electrognathography was used to track and analyze the trajectory and range of eccentric mandibular movements, while angular parameters relative to the horizontal plane were derived from the recorded motion data. Surface electromyography was employed to assess bioelectrical activity, as well as the symmetry and synergy of the masticatory and temporalis muscles. The data collected from the main group were analyzed at different treatment stages and compared with the corresponding data from the control group. Occlusal stabilization appliances and temporary fixed dental restorations were fabricated using milling technology, incorporating CBCT imaging, intraoral scanning, and occlusal registration following transcutaneous electrical nerve stimulation (TENS).

Results. In the main group, surface electromyography (sEMG) during the relative physiological rest test revealed a 60.3% average reduction in the bioelectrical activity of the masticatory muscles compared to baseline values before treatment. During the maximum voluntary clenching test, an increase in muscle symmetry of 89.5% on average was observed, while muscle synergy improved by 61% compared to baseline values. According to electrognathographic data, after prosthetic treatment, the main group demonstrated an average 71% increase in the range of eccentric occlusal movements of the mandible, as well as a 77% average reduction in the variability of angular parameters of eccentric occlusal movements compared to baseline values.

Conclusion. The use of an advanced digital treatment protocol for temporomandibular disorders (TMD) involving both joint and myofascial dysfunction, based on individualized parameters for modeling occlusal stabilization appliances and temporary fixed dental restorations, as well as functional diagnostics and outcome monitoring, ensures stable and reliable rehabilitation outcomes for patients.

1. Strekalova EL, Dzhasheeva DI, Khalkecheva LN, Strekalov AA. Analysis of epidemiological aspects of TMJ disorders at the first prosthodontic appointment. Institute of Dentistry. 2021;90(1):14-15 (In Russ.). Available from: https://www.elibrary.ru/item.asp?id=45632811

2. Arsenina OI, Abakarov SI, Popova NV, Makhortova PI, Popova AV, Zhukov DYu. Orthodontic treatment as a stage of rational dental prosthetics. Stomatology. 2023;102(2):54 62 (In Russ.). doi: 10.17116/stomat202310202154

3. Dubova LV, Zolotnitsky IV, Stupnikov AA. Use of a functional diagnostic complex in orthopedic treatment of patients with functional morphological disorders of the TMJ. Russian Dentistry. 2019;12(3):65-66 (In Russ.). Available from: https://www.elibrary.ru/item.asp?id=44018007

4. Dubova LV, Stupnikov PA, Stupnikov АА, Burenhcev DV, Kharchenko DA. The rationale for the algorithm of comprehensive digital diagnosis of patients with temporomandibular disorders using an intraoral occlusal appliance. Parodontologiya. 2021;26(4):260-268 (In Russ.). doi: 10.33925/1683-3759-2021-26-4-260-268

5. Saakyan MU, Uspenskaya OA, Ryabov SV, Aleksandrov AA. Determination of errors in the manufacturing technology of occlusive splints for the treatment of TMJ diseases. Actual problems in dentistry. 2020;16(2):129- 133 (In Russ.). doi: 10.18481/2077-7566-20-16-2-129-133

6. Nota A, Chegodaeva AD, Ryakhovsky AN, Vykhodtseva MA, Pittari L, Tecco S. One-Stage Virtual Plan of a Complex Orthodontic/Prosthetic Dental Rehabilitation. Int J Environ Res Public Health. 2022 28;19(3):1474. doi: 10.3390/ijerph19031474

7. Ryakhovsky AN, Vykhodtseva MA. Validation of the technique of TMJ 3D analysis based on computer tomography. Stomatologiia. 2022;101(1):23-32 (In Russ.). doi: 10.17116/stomat202210101123

8. Ryakhovsky AN, Losev FF, Altynbekov KD, Vykhodtseva MA. 3D analysis of anatomical and functional parameters of TMJ and their correlation. Stomatologiia. 2022;101(3):49-60 (In Russ.). doi: 10.17116/stomat202210103149

9. Stafeev AA, Ryakhovsky AN, Petrov PO, Chikunov SO, Khizhuk AV. A comparative analysis of reproducibility of the jaws centric relation determined with the use of digital technologies. Stomatologiia. 2019;98(6):83-89 (In Russ.). doi: 10.17116/stomat20199806183

10. Kihara H, Hatakeyama W, Komine F, Takafuji K, Takahashi T, Yokota J, et al. Accuracy and practicality of intraoral scanner in dentistry: A literature review. Journal of prosthodontic research (Japan). 2020;64(2):109–113. doi: 10.1016/j.jpor.2019.07.010

11. Kernen F, Schlager S, Seidel Alvarez V, Mehrhof J, Vach K, Kohal R, et al. Accuracy of intraoral scans: An in vivo study of different scanning devices. The Journal of prosthetic dentistry (USA). 2021;21:1–7. doi: 10.1016/j.prosdent.2021.03.007

12. Marcel R, Reinhard H, Andreas K. Accuracy of CAD/ CAM-fabricated bite splints: milling vs 3D printing. Clinical oral investigations (Germany). 2020;24(12):4607–4615. doi: 10.1007/s00784-020-03329-x

13. Park JH, Lee GH, Moon DN, Kim JC, Park M, Lee KM. A digital approach to the evaluation of mandibular position by using a virtual articulator. The Journal of prosthetic dentistry (USA). 2021;125(6):849–853. doi: 10.1016/j.prosdent.2020.04.002