Abstract
The purpose of this study was to examine the frequency of children with congenitallymissing permanent teeth (missing group) and to assess the growth anddevelopment of the missing group by referring to the dental age.
We assessed the development of the children by examining the differences betweenthe dental age and the chronological age. The dental age was determinedby the standard age of the Moorrees et al. tooth formation stage.
The materials were collected from 5,120 longitudinal orthopantomogramsand 4,850 dental x-ray photographs which were obtained from 1,623 Japanesechildren (795 male and 828 female), aged 5 to 10, at the Department of Pediatric Dentistry, Aichi-Gakuin University.
The results were as follows;
1. The frequency of the missing group was 10.9%. (male: 9.7%, female: 12.1%)
2. Approximately 86.4% of the missing group had either one or two congenitallymissing permanent teeth. (subjects missing one tooth: 53.1%, subjects missingto teeth: 33.3%)
3. The distribution of the congenitally missing permanent teeth showed that thelower second premolars were most frequently affected, followed by the lowerlateral incisors in both sexes.
4. There were no statistically significant differences between the dental age andchronological age of the missing group between sexes and ages.
5. The value of the differences between the dental age and chronological age ofthe missing group was larger than that of the non-missing group.
6. As the number of the congenitally missing permanent teeth increased, the valueof the differences between the dental age and chronological age of the missinggroup also increased.
