Third molar development by Demirjian's stages and age estimation among Brazilians

Abstract

Abstract Objective: To correlate the stages of 3M mineralization with the chronological age of South Brazilians and assess the prevalence of complete mineralization in the threshold of 18 years old (age of legal majority). Study Design: The sample consisted of 1,013 panoramic radiographs from South Brazilian subjects aged between 15 and 23 years old. Demirjian's Tooth Development Stages (1973) was applied to classify the 3M mineralization into 8 stages (from A to H). Results: Stages D, E, F and G were more associated with subjects aged under 18 years old, while stage H was associated with subjects older than 18 years old. A smaller part of the sample ageing 18 years old or above it, was found to be on stages D to G (9.1% and 16.9% for upper and lower 3M, respectively). Considering exclusively stage H, the probability of someone being above 18 years old is 96.4% for upper 3M for male and 88,2% for female, and for lower 3M, 95,1% and 78,4%, respectively. Males presented an earlier development of this dental element, but at stage H, this age difference was significant only for the lower arch (p=0.018). Conclusion: Demirjian's Tooth Development Stages can be a useful tool to assess 3M mineralization for age estimation. When analyzing the stage H, the probability of the individuals were above 18 years old is high, both male and female, in upper 3M or lower 3M. This sample has shown future studies should consider the influence of ethnic and genetic factors over 3M development.