Insufficient evidence for the applicability of the neonatal line as evidence for live birth in forensic odontology: a systematic review.

BACKGROUND

Female neonaticide is a widespread issue in India, with the majority of cases going unreported due to a lack of proper evidence. The prime objective of forensic investigation in neonaticide is to provide evidence against the claim of a stillbirth. The neonatal line is an incremental line corresponding to the event of birth that separates the enamel formed before birth from the enamel layer laid after birth. It is found in all developing teeth during birth, including all deciduous teeth and permanent molars. The presence of the neonatal line distinguishes live birth from stillbirth, and it is possible to estimate the exact period of survival of the infant by measuring the amount of postnatal hard tissue.

OBJECTIVE

To assess the applicability of the neonatal line as evidence of live birth in forensic odontology.

METHODOLOGY

The systematic review was registered in PRSOPERO with registration number CRD42023439753. The sources of data included Google Scholar, Scopus, and PubMed. The studies were evaluated for quality using the QUIN tool, which was specifically designed for analytical cross-sectional studies.

RESULTS

A search across PubMed, Scopus, Google Scholar, and gray literature identified 97 articles on neonatal line. After title review, 50 articles were dismissed for not meeting the review objectives. Abstract screening excluded 26 articles that were reviews or duplicates. Of the 21 articles that proceeded to full-text review, four met the inclusion criteria and were included in the qualitative analysis. A meta-analysis was not possible because of the considerable variability between studies.

CONCLUSION

The presence of an NL signifies a live birth, and by assessing the extent of postnatal hard tissue development, one can estimate the infant's survival in days, which might indicate neonaticide. Although several skeletal indicators can determine " whether an infant was born alive," these may not always be reliable. Therefore, NL could provide an additional method and act as a supplementary tool for investigations. However, the evidence is not robust enough to support its use in practical forensic odontology applications.

PROTOCOL REGISTRATION

The study protocol can be accessed in the PROSPERO database, which is the International Prospective Register of Systematic Reviews, with the registration number CRD42023439753.