Secondary Dentine — MFDS Part 1 MCQ

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ModeratePhysiologySecondary DentineMFDS Part 1

Histological examination of a vital mature permanent tooth shows a slowly increasing layer of dentine along the pulpal surface. It has formed after completion of root development, in the absence of caries, restoration, trauma or other local injury. Which type of dentine is this?

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Correct answer: A — Secondary dentine

Secondary dentine is the correct answer. It is deposited slowly by surviving odontoblasts after primary dentinogenesis and root development are complete. This physiological deposition continues throughout life and progressively reduces the dimensions of the pulp chamber and root canals. Primary dentine forms during development of the crown and root. Reactionary tertiary dentine is produced by surviving odontoblasts in response to a mild local insult, whereas reparative tertiary dentine is produced by newly differentiated odontoblast-like cells after more severe injury and odontoblast death. Sclerotic dentine results from mineral deposition within existing dentinal tubules, commonly with ageing or chronic irritation; it is not a newly deposited layer along the pulpal surface.

Reference: Nudel I et al. Secondary Dentin Formation Mechanism: The Effect of Attrition. International Journal of Environmental Research and Public Health. 2021;18(19):9961. https://pubmed.ncbi.nlm.nih.gov/34639261/