Effects of bruxism on temporomandibular joint internal derangement in patients with unilateral temporomandibular joint pain: The role of magnetic resonance imaging diagnostics.

Objective : This study compared temporomandibular joint (TMJ) magnetic resonance imaging (MRI) findings between bruxism and control groups with unilateral TMJ pain as well as the TMJ MRI findings for the painful and non-painful sides of individuals in the two groups. Methods : Clinical and MRI findings of patients seen at Uşak University, Dentistry Faculty, Department of Oral and Maxillofacial Surgery for unilateral TMJ pain between 2017 and 2020 were analyzed. Bruxism was diagnosed based on clinical findings and patient history. The MRI variables were disc/condyle relationship (normal, disc displacement with reduction, or disc displacement without reduction), disc structure (normal and abnormal), condyle degeneration type (normal, moderate, or severe), and joint effusion (absent or present). Pain was recorded based on a visual analog scale (VAS) numbered between 0 and 10. Statistical analyses were performed using IBM SPSS. The data were distributed non-normally according to the results of Kolmogorov-Smirnov tests. The Mann-Whitney U test was used to compare age and VAS. Chi-square tests were used to compare categorical variables. Statistical significance was defined as p < 0.05 Results : This study assessed the MRI records of 558 cases of TMJ pain. No significant differences in disc/condyle relation, disc structure, condyle structure, or effusion were observed between the control and bruxism groups ( p > 0.05). However, a significant difference in TMJ MRI findings was observed between the painful and non-painful sides of each individual in the control and bruxism groups ( p = 0.001, p < 0.001 and p = 0.004, p < 0.001, respectively). Conclusion : The results of this study established a relationship between the painful side for each patient and TMJ MRI findings. In particular, individuals with bruxism had a higher rate of TMJ internal derangement and effusion on the painful side.