Validating Dental Histology for Perinatal Age Estimation Using Human Deciduous Teeth

This study tests the accuracy of dental histology for perinatal age estimation using deciduous teeth from modern human infants of known age. We evaluate whether enamel and dentin incremental structures, particularly the Neonatal Line (NNL), can be used to provide a reliable estimate of chronological age.

Seventeen unerupted deciduous teeth from 14 full-term infants (0-164 days old) were analyzed from the Granada identified skeletal collection in Spain. Thin sections were examined under transmitted light and confocal microscopy to identify the NNL, cross-striations, and von Ebner's lines. Daily secretion rates (DSR) were measured across crown and root to calculate crown formation time (CFT) and root formation time (RFT), which were compared with the documented ages at death.

Mean enamel DSR was 3.38 μm/day, and mean root dentin DSR was 3.24 μm/day. Enamel DSRs varied between tooth types and crown regions. The NNL was identified in all individuals who survived birth and was absent in one stillbirth, confirming its reliability as an indicator of live birth. Prenatal CFTs fell within ranges reported for full-term gestation, supporting the interpretation that all individuals were born at term. Histologically derived ages differed from recorded ages by an underestimation of 8 to an overestimation of 1 day, with a mean difference of 1 day.

Deciduous dental histology provides an accurate estimate of chronological age for human juveniles in the year after birth. These findings suggest that perinatal age estimates derived from dental histology can be applied in bioarchaeological and forensic contexts.