Dentinogenesis — MFDS Part 1 MCQ

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EasyPhysiologyDentinogenesisMFDS Part 1

Following an injury severe enough to destroy the primary odontoblasts, which cells in the dental pulp provide progenitors that differentiate into odontoblast-like cells and form reparative dentine?

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Correct answer: B — Undifferentiated mesenchymal cells

The correct answer is B. When a severe stimulus destroys the original odontoblasts, undifferentiated mesenchymal stem or progenitor cells within the pulp proliferate and differentiate into odontoblast-like cells. These replacement cells then secrete the matrix of reparative tertiary dentine. By contrast, surviving mature odontoblasts respond to milder injury by producing reactionary dentine, so option A does not describe the progenitor source in this scenario. Fibroblasts maintain the connective-tissue matrix of the pulp, while macrophages have immune and phagocytic functions. Endothelial cells form the lining of pulpal blood vessels and do not normally generate reparative dentine.

Reference: Babb R, Chandrasekaran D, Neves VCM, Sharpe PT. Axin2-expressing cells differentiate into reparative odontoblasts via autocrine Wnt/β-catenin signaling in response to tooth damage. Scientific Reports. 2017;7:3102. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5465208/