A 20-year longitudinal study of subjective symptoms of temporomandibular disorders from childhood to adulthood.

The aims were to study the development over 20 years of reported temporomandibular disorders (TMD) symptoms in an epidemiologic sample and to analyze possible correlations between these symptoms and some other variables. Four hundred and two randomly selected 7-, 11- and 15-year-old subjects were originally examined by means of a questionnaire with regard to symptoms of TMD. The investigation was repeated after 4 5, 10, and 20 years, using the same method. After 20 years, when the original group had reached the age of 27 to 35 years, 378 individuals (94%) could be traced, and they were sent a questionnaire. Three hundred and twenty subjects (80% of the original sample, 85% of the traced subjects) completed and returned the questionnaire. There was a substantial fluctuation of reported symptoms over the 20-year period. Progression to severe pain and dysfunction of the masticatory system was rare. On the other hand, recovery from frequent symptoms to no symptoms was also rare. At the last examination 13% reported one or more frequent TMD symptom. The prevalence of bruxism increased with time, but other oral parafunctions decreased. Women reported TMD symptoms and headache more often than men. Correlations between the studied variables were mainly weak. The highest correlations found (rs = 0.4-0.5) were those between reported tooth clenching and tooth grinding and jaw fatigue. It can be concluded that in this epidemiologic sample, followed over 20 years from childhood to adulthood, a substantial fluctuation of TMD symptoms was found. Severe symptoms were rare, but 1 of 8 subjects reported frequent TMD symptoms at the last exam.