Distribution of temporomandibular disorders among sleep bruxers and non-bruxers-A polysomnographic study.

Introduction: Bruxism is often indicated as a risk factor for the occurrence of temporomandibular disorders (TMD). Despite the frequent co-occurrence of bruxism and TMD, the exact relationship between these phenomena has not been thoroughly explained, and their causal relationship is still considered controversial.
Aim: The aim of this study was to evaluate the distribution of TMD among sleep bruxers and non-bruxers.
Materials and Methods: The participants of this study were 77 patients of the Clinic of Prosthetic Dentistry operating at the Department of Prosthetic Dentistry, Wroclaw Medical University who had been diagnosed with TMD and probable sleep bruxism. Patients underwent video-polysomnography to assess the intensity of sleep bruxism using the Bruxism Episode Index (BEI).
Results: The following TMD diagnoses were made: local myalgia, temporal tendonitis, myofascial pain, myofascial pain with referral, hypertrophy, osteoarthrosis, disc displacement with reduction, disc displacement without reduction with limited opening, subluxation, adhesions/adherence, arthralgia, headache attributed to TMD and oromandibular dystonia. None of these occurred statistically significantly more often in the studied group (bruxers; BEI ≥ 2) than in the control group (non-bruxers; BEI < 2); (P > .05 for all comparisons).
Conclusion: The distribution of TMD among sleep bruxers and non-bruxers is similar. Therefore, the prevalence of sleep bruxism seems not to be a certain risk factor for TMD occurrence.
(© 2020 John Wiley & Sons Ltd.)