Temporomandibular disorder: otologic implications and its relationship to sleep bruxism.

INTRODUCTION Temporomandibular disorder is an umbrella term for various clinical problems affecting the muscles of mastication, temporomandibular joint and associated structures. This disorder has a multifactor etiology, with oral parafunctional habits considered an important co-factor. Among such habits, sleep bruxism is considered a causal agent involved in the initiation and/or perpetuation of temporomandibular disorder. That condition can result in pain otologic symptoms. OBJECTIVE The aim of the present study was to investigate the relationship between temporomandibular disorder and both otologic symptoms and bruxism. METHODS A total of 776 individuals aged 15 years or older from urban areas in the city of Recife (Brazil) registered at Family Health Units were examined. The diagnosis of temporomandibular disorder was determined using Axis I of the Research Diagnostic Criteria for temporomandibular disorders, addressing questions concerning myofascial pain and joint problems (disk displacement, arthralgia, osteoarthritis and osteoarthrosis). Four examiners had previously undergone training and calibration exercises for the administration of the instrument. Intra-examiner and inter-examiner agreement was determined using the Kappa statistic. Individuals with a diagnosis of at least one of these conditions were classified as having temporomandibular disorder. The diagnosis of otologic symptoms and bruxism was defined using the same instrument and a clinical exam. RESULTS Among the individuals with temporomandibular disorder, 58.2% had at least one otologic symptom and 52% exhibited bruxism. Statistically significant associations were found between the disorder and both otologic symptoms and bruxism (p<0.01 for both conditions; OR=2.12 and 2.3 respectively). Otologic symptoms and bruxism maintained statistical significance in the binary logistic regression analysis, which demonstrated a 1.7 fold and twofold greater chance of such individuals have temporomandibular disorder, respectively. CONCLUSION The logistic regression analysis demonstrated strong associations between the disorder and both otologic symptoms and bruxism when analyzed simultaneously, independently of patient age and gender.