Predictors of signs and symptoms of temporomandibular disorders: a 20-year follow-up study from childhood to adulthood.

The aim of this study was to find possible predictors of signs and symptoms of temporomandibular disorders (TMD) in a long-term perspective. Baseline questionnaire and clinical examinations focusing on function and dysfunction of the masticatory system were performed in a sample of 402 subjects 7, 11, and 15 years old. After 20 years, 320 subjects (80% of the original sample) completed a similar questionnaire as at baseline. From the oldest age group, now aged 35 years, 100 subjects (74% of the original sample) also attended a clinical examination. Three variables from the 20-year follow-up were chosen as dependent variables in logistic regression analyses, with independent variables selected from the baseline examinations. Three variables at baseline were significant predictors for reported TMJ clicking at the 20-year follow-up, tooth wear index being the strongest (odds ratio = 4.3). Reported TMJ clicking at the start was the only significant predictor for TMD symptoms without clicking 20 years later (odds ratio = 2.3). The third logistic regression model, using the Helkimo Clinical Dysfunction Score as dependent variable, resulted in four significant predictors from the baseline examinations (bruxism, oral parafunctions, TMJ clicking, and deep bite). The results indicated that some signs and symptoms might predict TMD signs and symptoms in a long-term perspective. However, it cannot be concluded from this study whether these symptoms recorded in childhood--oral parafunction, tooth wear, TMJ clicking, and deep bite--can be used for predicting manifest TMD in adult age.