Abstract
The purpose of this study was to investigate the incidence of congenital abnormalities of deciduous teeth including fused teeth, congenitally missing teeth, peg-shaped teeth, and supernumerary teeth, and their relation to maternal and child conditions during pregnancy or delivery. The abnormalities were also studied from the hereditary aspect. The subjects were 12, 812 children aged three years who visited the East Health Center in Fukuoka City for dental health examination during 1983-1990.
Fused teeth had the highest incidence. The incidence of fused teeth was 4.77%, including the incidence of congenitally missing teeth. Fusion of central and lateral incisors was observed with the highest freqency. Total rate of incidence of congenital abnormalities was 4.89%. No significant longitudinal changes in the rate of incidence were seen during the period of investigation. However a marked elevation of the rate of incidence of abnormalities during the past 50 years was suggested by comparison with data reported previously in Japan. Most of the abnormalities (91.5%) were found in the lower teeth. Incidence on the right side was significantly higher than on the left side. Incidence of abnormalities in deciduous teeth has no significant relation to maternal abnormalities during pregnancy, maternal age, or the weight of the child at birth. Bilaterally occurring abnormalities and fusion of canine and lateral incisors showed stronger hereditary influence than other types of abnormality.
