Mandibular dysfunction in adolescents. II. Prevalence of signs.

The prevalence of signs of mandibular dysfunction was studied in 285 17-year-old adolescents living in the municipality of Skellefteå. They were subjected to a functional examination of the masticatory system. The commonest clinical signs were tenderness to palpation of the masticatory muscles (41%) and clicking sounds from the temporomandibular joints (22%). The tenderness to palpation was generally located to the lateral pterygoid muscle and the insertion of the temporal tendon. Girls were tender to palpation oftener (p less than 0.05) than boys. Unilateral contact in the retruded position was recorded in 77% of the subjects. Mediotrusion interferences were found in 30% of the subjects. Signs of clinical dysfunction were found in 56% and were significantly commoner in girls than in boys (p less than 0.01). Since mild and moderate signs of mandibular dysfunction obviously make an early appearance, a routine dental examination should include a functional evaluation of the stomatognathic system, to identify patients who should be observed more closely.