Incidence and prevalence of myofascial pain in the jaw-face region.: A one-year prospective study on dental students

Objective. The aims of this study were to examine the 1-year period prevalence, incidence, and course of myofascial pain in the jaw-face region, and to analyze whether female gender, dental occlusion, and oral parafunctions have any influence on these signs and symptoms. Material and methods. The study population comprised 308 dental students examined at the start of their dentistry course and re-examined after 1 year. Case histories were collected using a questionnaire. The clinical examination included palpation sites of muscles, a submaximal clenching test, measurements of maximal mandibular mobility, and classification of morphological and functional dental occlusion. Results. The 1-year period prevalence of frequent myofascial symptoms was 19%. The incidence of myofascial pain, according to the Research Diagnostic Criteria for TemporoMandibular Disorders (RDC/TMD), was 4%. The female students presented an almost 4-fold incidence rate of myofascial symptoms compared to the male students. Non-symptomatic subjects were found predominantly among men, among those unaware of bruxism with bilateral contact in the retruded contact position (RCP), and among those with a stable intercuspal position (ICP). Variations in morphological occlusion did not show any relation to myofascial symptoms, nor did contact patterns in eccentric positions. Conclusions. Female dental students were more prone to developing frequent myofascial pain and to perceiving local muscle soreness than were male students during a 1-year period. Both self-reported bruxism and registered mandibular instability in ICP showed association with the 1-year period prevalence of myofascial signs and symptoms in the jaw-face region.