Estimating ages by third molars: stages of development in Brazilian young adults

The purpose of this study was to estimate age through the analysis of third molar stages of development in Brazilian young adults. A cross-sectional study was conducted by analyzing 659 panoramic X-rays. Two techniques were used to establish the stages: Modified Scoring (MST) and Demirjian (DT). Regression formulas were calculated. Statistical analyses were conducted by t, Kappa tests, and simple and multiple linear regressions (5% level of significance). Out of the participants, 40.7% were female and 59.3% were male, with ages from 15-22 years. The Kappa test showed good results for intra-observer (0.84 for MST and 0.95 for DT) and inter-observer examination (0.81 for MST and 0.92 for DT). Differences were found in the stages of tooth formation between male and female, but differences were not observed between the left and right sides. We found that both DT and MST underestimated the ages in about 6 months, depending on the used classification and number of teeth. These methods are appropriate for assessing the ages of young Brazilians, although the DT showed better reproducibility.