EPIDEMIOLOGICAL STUDY ON DENTAL CARIES IN TWINS.

쌍생아(雙生兒) 치아(齒牙) 우식증(齲蝕症)에 관(關)한 역학적(疫學的)인 연구(硏究)

The Study reported here was designed to analyze the prevalence of Dental Caries in the primary teeth of monozygote twins, and to ascertain and compare the intrapair differences with the intrapair differences in control pairs. The prevalence of dental caries in the primary teeth of 40 pairs of presumably monozygote twins, based on phenotypic analysis, was studied. The age range was from 3 to12 years. The control group consisted of pairs that included a twin chosen at random and an unrelated child of the same sex and age, so that for each pair of twins there was a corresponding control pair. The clinical examination was carried out by an operator using an oral mirror and sharp explorers, and with good lighting. 40 pairs of twins were examined with a total of 4,950 primary tooth surfaces (990 primary teeth) and 40 control pairs with a total of 4,935 primary tooth surfaces (987 primary teeth). Five surfaces were considered for each tooth. After the def individual index was determined, the ratio between this index and the number of examined surfaces was established in each case, the cer (Caries experience rate) index. The def and cer averages were determined for the subjects and the controls. All intrapair differences in twin and control groups were compared following the paired sampling method. The following conclusions were made: 1. Intrapair differences in the control group were significantly greater than in twins, when defs, ds, es, fs, and cer were compared. 2. The genotype appeared to be a determining factor in dental caries susceptibility or resistance, although the environment played an important role as well. 3. Intrapair differences in American children were significantly greater than in Korean when defs, es, fs, and cer were compared, but ds was equal.