Joint epidemiological longitudinal dental survey in Nigeria, especially in comparison with that of Japanese.

Since 1980 we carried out a longitudinal dental survey in Ile-Ife, as a joint study with the dental school of Ife University, Nigeria, being supported by A Grant under The Monbusho International Scientific Research Program for ten years. One thousand one hundred seventy-one children and adults were examined in the 1991 survey. The data were compared with the data in the previous survey and Japanese survey. Results were as follows: 1) Caries prevalence rate and the average number of DMFT were still very low, especially showing that both the caries prevalence and the average number of DMFT decreased in the rural areas because the attrition proceeded faster than the caries, 2) Nigerian deciduous and permanent dentition were larger than in the Japanese in all items measured, 3) the condylar head was transformed from the round shape to the ultra-flat shape with age, 4) there was a fewer incidence of severe periodontal diseases despite of the marked deposition of calculus, 5) with respect to Nigerian foods, there was no difference between the rainy and dry seasons in both the urban and rural communities, 6) the weaning period of the baby is decided by their mother, taking care of the health of the baby, almost all babies at one year to two years and a few at three years and 7) the menu for the breakfast, lunch and supper of the baby was made considering the nutritional aspect of the baby.