Two-year longitudinal study of signs of mandibular dysfunction in adolescents.

Signs of mandibular dysfunction in adolescents were studied longitudinally from the age of 17 to 19 years. Totally, 27 subjects dropped out, leaving 258 for the longitudinal intraindividual comparisons. TMJ sounds were found in about one-fifth of the adolescents and were recorded significantly more often in girls than boys from the age of 18 years. The frequency of muscles tender to palpation fluctuated somewhat between the annual examinations. At the first and second examination muscle tenderness was statistically significantly commoner in girls than in boys. Except for TMJ sounds and muscle tenderness signs of mandibular dysfunction were rare. About half of the subjects had signs of mandibular dysfunction, mostly of mild character. Girls regularly had significantly higher dysfunction index (Di) values than boys. No change between the annual recordings was noted in 60% of the individuals, and impairment and improvement had occurred about equally often. In 29%, signs were recorded all years.