Preliminary Survey on the Temporomandibular Disorders in Dental Populations of Japan

Part I: Prevalence of age groups and area differences in Japan

Abstract

Prevalence of temporomandibular disorders (TMD) was surveyed within 2 weeks by questionnaire for all the patients of 183 dental clinics in Japan. Valid answer of 16, 748 was obtained and analyzed. Signs and symptoms of TMD were found in 13.6% of the patients with 9.9% for male and 17.3% for female (P<0.001) . Distribution of the prevalence of the patient with the TMD findings showed that female was greater than male in each age and smooth curve was exhibited as a whole with a peak at the later 30 years of age. The prevalence showed a tendency of remarkable increase from 11 years and gradual decrease from 50 years of age. Area difference was not recognized statistically.