Echoes from birth--mutual benefits for physical and forensic anthropology by applying increment counts in enamel of deciduous teeth for aging.

The present study aims to compare metrical and morphological features of skeletal and dental development in two skeletons of very young infants from different archeological sites in Syria with the results of the microscopic approach of age-at-death estimation based on the neonatal line (NNL). Here, the presence ofa NNL is used as an indicator of birth survival and the duration of the lifespan post partum is assessed by counting prism cross-striations (PCS) external to the NNL. In the literature, PCS have been determined to represent a circadian rhythm in human enamel formation. For both individuals, consistent results in terms of the presence of a NNL and the counts of prism cross-striations could have been obtained. In the younger individual evidence of a postnatal age at death of less than two weeks was documented. This study demonstrates that the use of the NNL as an individual landmark without the need for the reference to growth standards enables an estimation of age at death on skeletal remains of infants within much narrower ranges compared with metrical and morphological analyses. To date, presence of a NNL is the only way of documenting birth survival in skeletons of perinatal individuals. This method can be applied to forensic and bioarcheological skeletal material.