Scaling Relationships between the Neonatal Line and Tooth Enamel Morphology

Abstract

Context: The neonatal line (NNL) forms shortly after birth in the enamel of human children’s deciduous teeth. There is evidence that the dimensions of the line may be indicative of infants pre- and early postnatal health. Thus, there is potential for the NNL to be measured and used as a biophysical marker of early developmental stress in children. It is for this reason that researchers studying the Developmental Origins of Health and Disease (DOHaD) are interested in the NNL, and whether it can be used to help diagnose future risks of ill-health. However, to date research has yielded inconsistent results, and thus a deeper understanding of NNL formation could bring about more consistency in future research linking NNLs and infant health. Design: Using teeth collected from a contemporary population in Australia (n = 45), this study investigated scaling relationships between NNL thickness and enamel morphology. Results: Statistically significant differences were found in enamel thickness between tooth types, but not in NNL width. Across all tooth types, relative enamel thickness (RET) was found to have a statistically significant correlation with NNL width. In only incisors, all measurements of enamel thickness (RET, average enamel thickness, linear enamel thickness, and prism path enamel thickness) had a statistically significant correlation with NNL width. Conclusions: Results from this investigation provide evidence that a scaling relationship exists between enamel thickness and NNL width. No previously published paper has reported such results. The scaling relationship between enamel thickness and NNL width identified in this thesis may have been an unknown confounding factor in past research. Future research interpreting NNLs may be improved by accounting for this factor. Show more