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.