Studies of deciduous enamel have concluded that the birth process and perinatal disorders result in the formation of a widened neonatal line and/or neonatal enamel hypoplasia. A widened neonatal line has been associated with a complicated delivery, neonatal difficulties at birth, maternal complications at birth, infant birthweight and short gestation length. The present study measured the width of the neonatal line in a sample of forty-five primary teeth collected from Canadian children. Birth history information was gathered through in depth interviews with the mothers of children donating teeth. Statistical testing was carried out to determine if significant differences exist in neonatal line width between groups of children with respect to birth trauma, neonatal health, maternal health and term at birth. A preliminary investigation of the effect of birth duration on the width of the neonatal line was undertaken. Line width differences between tooth classes were also considered. The results of the current study were compared to those of earlier clinical studies of the neonatal line and enamel hypoplasia. The present data demonstrates that neonatal line width varies within the tooth crown and between tooth classes; a range of widths also exists within individual specimens. The observed relationships between neonatal line width and birth trauma, neonatal health, maternal health, and term at birth were not consistent with those of earlier dental studies. These associations were dependent on the tooth class examined and the location of the width measurements within the tooth crown. No correlation was found between birth duration and the width of the neonatal line. The most troubling issue to emerge during the present study is the lack of a rigorous methodology in previous investigations of the neonatal line. This lack of procedural rigor may account for the discrepancies between the findings of the present study and those of earlier investigations. At present, the width of the neonatal line does not reflect the severity or the duration of the disturbance that caused it. Its use as a diagnostic tool in physical anthropology and during forensic investigations is not justified.

Master of Arts (MA)