Associations between mandibular torus and types of temporomandibular disorders, and the clinical usefulness of temporary splint for checking bruxism

Hee-Min Lee,Pil-Young Yun,Dong-Woo Kang,Il-Hyung Kim,Young-Kyun Kim

doi:10.1186/s12903-021-01550-y

Abstract

BackgroundOcclusal stress from oral parafunctional habits is one of the causes of temporomandibular disorders (TMD) and mandibular torus (MT). Although some studies have investigated the correlation between TMD and MT, understanding of the relationships between types of TMD and MT is insufficient. Therefore, we conducted this study to investigate the associations between presence of MT and TMD types.MethodsThis study included 77 patients diagnosed with TMD who first visited our clinic for TMD between March 2019 and July 2020. Among them, 30 (38.9%) had MT, and 54 (70.1%) had oral parafunction. Parafunctional activity during sleep was confirmed using a temporary splint for checking bruxism (TSCB).ResultsThe relationship between prevalence of MT and oral parafunction in TMD patients was not statistically significant (P = 0.131), but the odds ratio was relatively high at 2.267. An analysis of TMD type revealed that Type I, which is classified as myalgia of the masticatory muscles, and MT had a significant association (P = 0.011). We fabricated a TSCB for 27 patients to wear during sleep and confirmed that 23 (85.2%) had nocturnal bruxism. The TSCB results and presence of MT showed a significant relationship (P = 0.047).ConclusionThrough the results of this study, clinicians may consider the hyperactivity of masticatory muscles in the presence of MT when treating TMD patients. In addition, TSCB has a great diagnostic value as it can be easily manufactured and be useful for discovering pre-existing oral parafunctions that patients are not aware of.

Highlights

Occlusal stress from oral parafunctional habits is one of the causes of temporomandibular disorders (TMD) and mandibular torus (MT)
It is convincing that oral parafunctions such as clenching or teeth grinding are closely related to the occurrence of MT as well as TMD
TMD patients in this study showed higher prevalence of MT and nocturnal bruxism compared to the general population

Summary

Introduction

Occlusal stress from oral parafunctional habits is one of the causes of temporomandibular disorders (TMD) and mandibular torus (MT). Among various causes, microtrauma continuously applied to the region due to excessive masticatory function and occlusal stress due to oral parafunction is a major risk factor for TMD [4, 5]. Mandibular torus (MT) is a benign bone growth with clear border and slow growing rate. It mostly appears on lingual side of bilateral mandible premolar. The cause of MT is not understood, occlusal stress and excessive masticatory function have been suggested as the major factors [6,7,8]. Some studies have reported the relationship among TMD, oral parafunctions, and MT [6, 9], while some studies have reported on the relationship between oral parafunctions and MT [7, 9, 10]

Methods

Results

Discussion

Conclusion