Prevalences of malocclusions and dental caries in molars in female adolescents.

Prevalences of malocclusions and dental caries in molars were investigated on a database of high school students collected between 1977 and 1986. A total of 6,665 schoolgirls were evaluated. The proportions of 54.1% in the seventh grade and 56.6% in the tenth grade students were judged as having malocclusions. The prevalences of dental caries for the lower first and the second molars were significantly higher (p less than 0.001) than those for the upper opponents during the observation period. The prevalence of dental caries increased linearly for all kinds of molars in accordance with age, but they were lower than those reported by the Ministry of Health and Welfare in Japan determined for the entire nation. The percent of dental caries for the second molars revealed abrupt increases from 10% at the seventh grade to 50% at the 12th grade. These changes were particularly noticeable between the eighth and the tenth grades. These results suggest the significance of oral health care education during the adolescent period based on a long-term cooperation made by dentists, school nurses, teachers through the participation of students into the oral health care programme.