Prediction of demand for treatment of temporomandibular disorders based on a 20-year follow-up study.

The purpose was to test the hypothesis that signs and symptoms characteristic of temporomandibular disorders (TMD) at age 15 would predict demand for treatment during a 20-year follow-up period. Of originally 135 examined 15-year-old subjects, 103 completed a questionnaire and 84 were examined clinically at the 10-year follow-up (at age 25). After 20 years (at age 35), 114 completed a questionnaire and 100 were also examined clinically. During the 20-year follow-up period, 21 subjects received some kind of treatment of TMD. At baseline (age 15), the treated group reported tooth grinding at night more often than the non-treated group (P = 0.0042). At the 10-year follow-up (at age 25), the treated group reported more symptoms of TMD and oral parafunctions than the non-treated group. Among the clinical registrations, there was only one significant difference between the groups: anterior tooth wear was more extensive in the treated group. At the 20-year follow-up (at age 35), the treated group reported significantly more symptoms of TMD and oral parafunctions than the non-treated group. The clinical dysfunction index was also higher in the treated group. Logistic regression revealed tooth grinding at night as a significant predictor of received treatment of TMD. However, the positive predictive value was low whereas the negative predictive value was high (90%). The findings indicate that nocturnal tooth grinding is related to demand for treatment of TMD.