Prevalence of signs and symptoms of temporomandibular disorders in children and adolescents with and without crossbites.

This study investigated the prevalence of signs and symptoms of temporomandibular disorders (TMD) in 1,134 orthodontically untreated children and adolescents (593 boys, 541 girls; age range 5 to 15 years) with and without crossbites. The sample with crossbites was further grouped according to the type (anterior, posterior, unilateral, or bilateral). The TMD symptoms bruxism (obvious active attrition/myalgia), joint sounds (clicking/crepitation), deviation during opening, reduced functional movements (maximum opening <40 mm), and myopain (originating in the masticatory muscles/related to masticatory functions) were evaluated based on the standardized RDC/TMD protocol (Research Diagnostic Criteria for Temporomandibular Disorders) and compared among the various groups. Girls had a significantly higher prevalence of myopain than boys (x(2)=3.882, P<.05). Furthermore, individuals with posterior unilateral crossbites showed a significantly higher prevalence of TMD symptoms (x(2)=33.877, P<.001) and reduced functional movements (x2 = 10.800, P<.05) than any other group. In conclusion, sex and type of crossbite play a role in the prevalence of TMD signs and symptoms.