ナイジェリア人の歯垢，歯石，歯肉炎の分布に関する疫学的研究

In 1991, dental health examination was carried out in Nigeria : ILE-IFE (urban) and Ashipa (rural) located in the southwest of Nigeria. The number of the subjects was 205 (aged 8, 10, 12) in ILE-IFE and 511 (aged 8, 10, 12, 15 to 75) in Ashipa. The purpose of this study is to clarify the distribution of plaque, calculus and gingivitis and to reveal the correlation between the plaque score (DI-S, OHI-S), calculus score (CI-S, OHI-S) and gingivitis score (GI) among the Nigerian by age. Results were as follows: 1. In the comparison between urban and rural schoolchildren, CI-S was higher in the rural children statistically but DI-S was not. This evidence is to be expected as a consequence of using PACO (traditional twig) for tooth brushing, because 73.1% of rural children were using the PACO whilst 92.1% of urban children were using the tooth-brush. 2. Because of the poor oral cleanliness using PACO, the changing pattern of DI-S, CI-S and GI by age could be natural and physiological. 3. DI-S and CI-S among the rural people were of a high level in the children 8 and 10 years of age and decreased to the bottom level in the 20's. After the lowest scores in the 20's, these increased with age. 4. The correlations between DI-S and GI were higher in the young people than in the elder people.