台湾人の第 1 大臼歯の萌出および齲蝕罹患に関する疫学的研究

Abstract

In 1987 a survey on the eruption pattern and dental caries prevalence in 1st molars was made on 830 children (424 boys and 406 girls) between 5 and 12 years of age in the middle region of Taiwan. It is very important to prevent dental caries of 1st molars from the period beginning with their eruption because they have the highest dental caries susceptibility. Recently, dental caries prevalence of the lower-aged population in Taiwan has increased. The aim of this survey was to determine the measurement of dental caries prevention to contribute to public dental health care in Taiwan. The eruption index of 5- and 6-year-old children was higher, but the index of 8- and 9-year-old children was lower in lower 1st molars than in upper ones in both boys and girls. After 10 years old, all 1st molars showed complete eruption. Between 5 and 7 years old, the index of girls tended to be higher than that of boys in both upper and lower 1st molars. The A type of eruption was more frequent in both lower aged boys and girls, and the percentage of the A type decreased with age, while the P type of eruption increased with age in both boys and girls. In 5- to 7-year-old girls, the percentage of the P type was higher when compared with boys. The symmetry of eruption pattern was most frequent for lower 1st molars in both boys and girls at the ages of 5 and 6. The percentage for right 1st molars which showed symmetry was similar to that for left 1st molars, as equal as that for upper 1st molars, in both boys and girls at each age. In the 5-year olds in which 1st molars began to erupt, few boys and girls had decayed teeth, the number increased with age and reached about a half of all the 1st molars in 9-year-old boys and 7-year-old girls. The mean number of DMF teeth of 1st molars tended to be higher in girls than boys ; especially significant differences were found in 7 and 10 years old children. The mean numbers of DMF tooth-surfaces were significantly higher in girls than in boys at the ages between 9 and 11. The percentage of DMF teeth tended to be higher in girls than in boys ; especially significant differences were shown in 7- and 9 to 12-year old children. The A type of dental caries prevalence pattern decreased with age, while the P type increased with age in both boys and girls. The percentage of the P type tended to be higher in girls than in boys. The symmetry of caries prevalence pattern was seen highest in the lower 1st molars in both boys and girls, except in 12-year-old boys. The percentage for right 1st molars which showed symmetry was similar to that for left 1st molars in both boys and girls. Actual dental health capacity decreased with age in both boys and girls. In over 5 year olds, the capacity tended to be lower in girls than in boys ; especially significant differences were shown in children at the ages between 9 and 11.