An epidemiological study of supernumerary primary teeth in Japanese children: a review of racial differences in the prevalence

OBJECTIVE: To clarify the prevalence of supernumerary primary teeth in Japa nese children, we evaluated this prevalence in a sample of 8122 children ag ed 3-6 years, Furthermore, we undertook a statistical comparison of the fin dings of the present study with those of previous investigations on the pre valence of supernumerary primary teeth in Japanese, Chinese and Caucasian c hildren, SUBJECTS: The subjects used in the study consisted of 8122 children aged 3- 6 years (4102 boys and 4020 girls). The children were examined in kindergar tens. METHODS: The prevalence of supernumerary primary teeth was recorded by visu al inspection. Statistical analysis was carried out using the chi(2) test. RESULTS: Four cases of supernumerary primary teeth were found among the chi ldren examined, and thus the prevalence was 0.05%. All of the supernumerary primary teeth were located in the maxillary lateral incisor area, CONCLUSIONS: The prevalence in a sample of 8122 Japanese children was 0.05% and that in a combined sample of 65 068 Japanese children was 0.06%.