Development of third molars in Korean juveniles and adolescents

The aim of the present study was to provide reference data of the Korean population which is adequate to compare with other mongoloid populations and can be applied to the age estimation of Korean juveniles and adolescents. A cross-sectional study was performed on a randomly selected sample of 3301 orthopantomographs taken of patients aged from 4 to 26 years, and the developmental stages of the third molars were evaluated based on Demirjian's stages. The results showed that the development of third molars in the Korean population was likely to begin at age 7 in both males and females and be completed by age 22 in males and 24 in females at the latest, and the level of development of all four third molars correlated significantly with age in both genders. There were significantly more subjects without third molars in females than in males, however, subjects with all four third molars were significantly more common in males than in females. The Demirjian's stages C, F and G could be used as a reference stage to determine dichotomously whether a Korean is more likely to be under or above age 14, 18, or 20, respectively. These results will provide a reference for age estimation of Korean juveniles and adolescents and enable comparison with results from other ethnic populations.