A STUDY OF DENTAL ANOMALIES

치아이상에 관한 연구

The purpose of this study was to find out the prevalence of dental anomalies in 600 normal persons (male:363, female:237) at age 14 to 39 years, through history taking, oral examination, and radiographic observations of subjects. The obtained results were as follows: 1. The prevalences of individual dental anomalies were as follows; Congenitally missing teeth 7%; supernumerary teeth 1.33%; ectopic eruption; 8.50%, transposition;0.33% rotation; 23.67%, microdontia;11.16%(peg lateralis;5.33%, third molar;5.83%), prolonged retention of deciduous teeth;1.33%, crowding 49.83%, and spacing;15.17%. 2. Alterations in numbers of teeth : The most frequently missing teeth were mandibular lateral incisors, followed by mandibular second premolars and maxillary second premolars. In numbers of congenitally missing teeth per person, 52.38% had one missing tooth and 30.95% had two missing teeth. In supernumerary teeth, there was higher rate in male than in female. Most supernumerary teeth were mesiodens of median area in maxilla and the eruption pattern of that teeth generally was unerupted state. 3. In transposition, exchange of position of teeth involved the canine and first premolar. 4. Congenital missing rate of permanent successors in prolonged retention of deciduous teeth was 69.23%. 5. Crowing and spacing had respectively higher rate in mandible and in maxilla.