A comparison of Demirjian's four dental development methods for forensic age estimation in South Australian sub-adults

The aim of this study was to compare the accuracy of Demirjian's four dental development methods for forensic age assessment in a South Australian population. The sample comprised orthopantomograms (OPGs) of 408 sub-adult individuals (211 male; 197 female) with an age range of 4.9–14.5 years. The OPGs were obtained from various dental schools and clinics in urban Adelaide. The following Demirjian methods were evaluated: the original 7-tooth technique; the revised 7-tooth system; the 4-tooth method; and the alternate 4-tooth approach. The left mandibular teeth in each OPG were assessed and rated according to the eight stages (A–H) defined and illustrated in Demirjian et al.5 Differences between chronological and estimated ages were calculated for males and females separately; 95% confidence intervals of mean age differences were calculated and ANOVA used to assess the significance of mean differences.When comparing all four methods there were significant differences overall (and in individual age groups) between mean chronological and estimated age in both sexes. In addition, each method consistently overestimated chronological age. We also demonstrate that the accuracy of the dental age methods evaluated varies in different subsets of an Australian population, a finding that parallels previous research in other global populations. Based on our analyses we conclude that population-specific standards based on dental maturity curves, as opposed to estimated ages, would provide more accurate and statistically robust age estimations.