Second and Third Molar Calcification in Relation to Chronological Age in Koreans

The growth and development of tooth has a periodical characteristics that after complete development of canine and premolar at puberty, only the third molars continue development and for the third molar, there are individual variations in morphology, size eruption period, and rate of development, moreover, the rate of congenital missing is higher than that of the other teeth However, in the case that other biological references for age estimation are not present, third molar would be a valuable reference There have been a number of studies on the development of third molar in Korea However, since the state of tooth development vanes with years and nutritional differences, renewal of reference data considering the development change of third molar In accordance with the times Additionally, variation of age estimation may be observed as to which tooth, second and third molar had been used when second and third molar develop simultaneously Therefore, through comparison between the developmental degree of second molar and third molar, clarification of the interrelation between the two molars is required to be used as reference Hence, for the study of second and third molar calcification in relation to chronological age in Koreans, orthopantomograrns of 1,280 healthy patients who visited dental hospital, college of dentistry, Yonsei University were examined and recorded by two examiners independently, according to the reference were suggested by Demirjian et aI, and modified by Solan and Abramovitch The age of the patients ranged from 7 to 22, 40 people at each age with 640 males and females The orthopantomograms of the patients who had the specific medical or dental histories which could affect tooth development are excluded in this study to avoid false results. The results were as follows. 1. In the case of male, 98.3% of the sample showed one or more third molars formation, and that of female was 94.2%. 2. The reliability between the two examiners showed high enough in every cases There was no significant inter-observer effect. 3. In the case of the same teeth bilaterally within the same jaw and the same teeth unilaterally In upper and lower jaw, every cases of second molar resulted in high correlation For the third molar, within the same Jaw resulted in high correlation but same teeth unilaterally in upper and lower Jaw resulted in low correlatio. 4. The range of age that is appropriate for application of second molar m age estimation is below the age of 15 yedrs, and for third molar is 16 to is-year-old. 5. In case of third molar, the probability that the age would be higher than 18 years at specific calcification stage is calculated In every situation, at stage higher than stage F1, the value of probability was more than about 50% The probability of mandible was higher than that of maxilla, and the probability of female was higher than that of middle. Based on the results, this study could suggest the data about second and third molar calcification in relation to chronological age In Koreans, and It will be applied more accurately m age estimation for human Identification.ope