Gestation Length, Mode of Delivery, and Neonatal Line-Thickness Variation

The transition from an intra- to extra-uterine environment leaves its mark in deciduous teeth (and first permanent molars) as an accentuated enamel incremental ring called the neonatal line (NL). This prominent microfeature separates the enamel formed during intrauterine life from that formed after leaving the womb. However, while the physical structure of this scar is well known, the bases of its formation are still a matter of investigation. In particular, besides the influence of the birth-related abrupt environmental and dietary changes and the role played by physiological factors such as hypocalcaemia, a direct relationship between NL thickness variation and the physical was trauma implied by the birth dynamics, the Caesarean, and the operative modes are apparently associated with the thinnest and the thickest lines, respectively.