Etiology of craniomandibular disorders: evaluation of some occlusal and psychosocial factors in 19-year-olds.

This study involved 264 19-year-old adolescents who comprised 93% of an epidemiologic sample followed longitudinally from the age of 17. Case histories as well as self-ratings of anxiousness and comfort in daily living were collected with the aid of a questionnaire. The clinical examination included evaluation of TMJ, muscles, jaw mobility, and occlusion. The number of contacting teeth in the intercuspal position during light pressure was the occlusal factor with the most significant relationships to symptoms of mandibular dysfunction. Being tense was significantly related to a number of signs and symptoms of mandibular dysfunction. The risk ratio of having craniomandibular disorders was about three times as high in the group with few contacting teeth in the intercuspal area compared to those with the most occlusal contacts. The group who estimated themselves as tense had a risk ratio of craniomandibular disorders 3.4 to 8.5 times higher than those who did not experience tension. When the groups were constructed on the basis of combination of tension and few contacting teeth, these factors seemed to potentiate the risk ratios to values from 3.9 to 21 times those with most occlusal contacts and no experience of being tense.