[Examination and treatment of dental caries in the Niigata Prefectural Institute of Total Training for the Mentally Retarded, colony Niigata Shiroiwa-no-Sato].

The purpose of this study was to learn about the prevalence of dental caries in mentally retarded individuals and to follow up the treatment of the caries. The study group comprised 144 severely retarded individuals (79 males and 65 females) aged 6-19 at the time of their admission to the Institute. Following results were obtained by analyses of their dental examination over a period of records in 15 years from 1973 to 1987 and of their treatment charts over a period of 8 years from 1980 to 1987. 1. The DMFT index at the time of their admission showed a tendency to increase gradually with age. In the DMFT index by age, there was no significant difference between that of the Institute and that of the Survey of Dental Disease by Ministry of Health and Welfare Japan in 1981. 2. The FT index was lower and the MT index was higher than the indices of the Survey, and each of differences showed a statistical significance for almost of all ages. Also in the proportion of both indices to the DMFT index, there were significant differences respectively. 3. During the 8 years between 1980 and 1987, 740 teeth were treated with 388 amalgam fillings (52.4%), 174 resin fillings (23.5%), 22 metal crowns (3.0%), 55 endodontic therapies (7.4%) and 101 extractions (13.7%). 4. After Our department started the treatment program in 1980, there were under 0.5 untreated teeth in each individual for each year. Moreover, missing teeth increased slightly in individuals who were on the register more than 2 years. 5. One of the 237 filled teeth (0.4%) and 2 of 21 endodontically treated teeth (9.5%) were extracted because of unfavorable prognosis during 8 years of the follow-up survey period.