THE STATISTICAL STUDY OF PREVALENCE OF CONGENITAL DENTAL ANOMALIES THROUTH DENTAL ROENTGENOGRAPHIC FINDINGS.

X-선상에 의한 선천성 치아이상의 발생빈도에 관한 통계학적 연구.

This study was undertaken in order to observe the prevalence of congenital dental anomalies especially that of oligodontia and supernumerary teeth in 1024 children at age from 4 to 14 years, through history taking, oral examinations, roentgenographic observations of subjects, and statistic analysis was made. The following results were obtained: 1. The prevalence of oligodontia in 1024 children was $6.45{\pm}.8$ percent with a total of 122 teeth absent in sixty-six subjects, excluding 3rd molars, and most of children (86.4%) who have congenitally missing teeth showed abscence of one or two teeth individually. 2. The teeth most frequently absent were the mandibular second premolar, maxillary second premolar, maxillary lateral incisor, mandibular central incisor, and mandibular lateral incisor in order. 3. There was no statistically significant difference found in tooth abscence in the following comparisons; .Male vs Female .Bilateral vs Unilateral .Maxilla vs Mandible .Right vs Left 4. The prevalence of supernumerary teeth in 1024 children was $4.79{\pm}.67$ percent with a total of 59 supernumerary teeth in forty-nine subjects, all of children who have supernumerary teeth showed one or two supernumerary teeth individually. 5. Statistically significant difference was found in supernumerary teeth in the comparison of male vs female, and they were more frequent in male.