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Neonatal Line — MFDS Part 1 MCQ

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ModeratePhysiologyNeonatal LineMFDS Part 1

A ground section of a primary tooth shows a prominent accentuated incremental line extending through both enamel and dentine and separating tissue formed prenatally from tissue formed postnatally. Which event does this line represent?

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Correct answer: B — Physiological stress associated with the transition at birth

The line described is the neonatal line, so B is correct. It is an accentuated incremental line produced by the physiological stress and major environmental transition associated with birth. It occurs in enamel and dentine that are forming at that time and marks the boundary between prenatal and postnatal tissue. An inherited matrix defect would produce a more generalised developmental abnormality rather than a discrete birth marker. Local trauma usually causes a localised defect, while excessive fluoride exposure principally alters enamel and does not create a corresponding birth line in dentine. Maternal vitamin D deficiency may disturb mineralisation but is not the specific event represented by the neonatal line.

Reference: Estivals J, et al. Insight into perinatal health by investigating the neonatal line: A systematic review. Archives of Oral Biology. 2025;177:106335. https://pubmed.ncbi.nlm.nih.gov/40543249/