Age estimation by the Cameriere's normalized measurements (CNM) of the single permanent mandibular tooth on a panoramic radiograph

In this study Cameriere's normalized measurements (CNM) of a single mandibular tooth were evaluated for age estimation on a sample of ortopantomographies (OPTs) of 2223 Italian children aged between 4 and 15years. Dental maturity was radiographically evaluated by CNM of the seven left permanent mandibular teeth (CNMi=Ai/Li, i=1,…,7); in monoradicular teeth, the distance (Ai, i=1,…,5) between the inner sides of the open apex was measured while in biradicular teeth (Ai, i=6, 7), the sum of the distances between the inner sides of the two open apices was calculated. Ai was normalized by the tooth length (Li, i=1,…,7). The intra- and inter-observer agreement of CNM measurements was almost perfect. Overall, analyzed mandibular teeth finished their development up to the age of 13, but the distribution of CNM varied among different locations. The final models included a tooth-specific CNM as the independent variable and explained from 76% (second molars) to 39% (first incisors) of the variance in chronological age. The bias and accuracy of these models, when applied to real-life data with no age limitation, were within acceptable range of differences in the forensic anthropology of children. Specifically, in all models mean of absolute differences between estimated and real age was within one year (0.67 for first incisors to 1.00 for canines). In conclusion this study showed that all mandibular teeth do not have equal applicability for age estimation suggesting that further evaluation on different samples is necessary to evaluate the usefulness of a single mandibular tooth for age estimation.