A longitudinal epidemiologic study of signs and symptoms of temporomandibular disorders from 15 to 35 years of age.

AIMS: To study the development over 20 years of signs and symptoms of temporomandibular disorders (TMD) in an epidemiologic sample and to analyze possible correlations between these signs and symptoms and some other variables.

METHODS: The original group comprised 135 randomly selected 15-year-old subjects who were examined clinically and by means of a questionnaire for signs and symptoms of TMD. The examination was repeated after 5, 10, and 20 years by the same methods. After 20 years, when the original group had reached the age of 35 years, 124 individuals (92%) could be traced, and they were sent a questionnaire and invited for a clinical examination. The response rate was high: 114 subjects (92%) completed and returned the questionnaire, and 100 subjects (81%) attended the clinical examination.

RESULTS: There was a substantial fluctuation of both reported symptoms and clinically recorded signs over the 20-year period, but progression to severe pain and dysfunction of the masticatory system was rare. In both the 15-year-old and 35-year-old subjects, 13% reported 1 or more frequent TMD symptoms. At age 35, only 3 subjects (3%) were classified as having severe or moderate clinical signs of dysfunction according to the Helkimo Index, fewer than in previous investigations. Women reported TMD symptoms and headache and had muscle tenderness and joint sounds more often than men. Correlations between the studied variables were mainly weak. Among the highest correlations found (rs = 0.4) were those between reported clenching and bruxing habits and TMJ sounds and jaw fatigue.

CONCLUSION: In this epidemiologic sample followed from age 15 to 35 years, a substantial fluctuation of TMD signs and symptoms was found over time. Progression to severe pain and dysfunction was extremely rare.