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Predentine Zone — MFDS Part 1 MCQ

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ModeratePhysiologyPredentine ZoneMFDS Part 1

In a histological section from a vital mature tooth, a narrow pale-staining band is present immediately adjacent to the odontoblast layer, between the odontoblast cell bodies and mineralised dentine. What does this band represent?

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Correct answer: E — Newly secreted dentine matrix that has not yet reached the mineralisation front

The band is predentine: newly secreted organic dentine matrix, rich in type I collagen, that has not yet mineralised. Odontoblasts deposit this matrix at the pulpal surface of dentine, after which it progressively mineralises at the predentine–dentine boundary. Fully mineralised dentine lies external to this band, so B is incorrect. Enamel matrix is produced by ameloblasts on the opposite side of the developing dentino-enamel junction, excluding C. Dead tracts are groups of dentinal tubules that have lost their odontoblastic processes, whereas sclerotic dentine contains tubules narrowed or occluded by mineral deposition; neither forms the normal band next to the odontoblast layer.

Reference: Pan H et al. The odontoblastic differentiation of dental mesenchymal stem cells: molecular regulation mechanism and related genetic syndromes, Figure 3 and accompanying text. Frontiers in Cell and Developmental Biology. 2023. https://pubmed.ncbi.nlm.nih.gov/37818127/