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Contraction Lines of Owen — MFDS Part 1 MCQ

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HardPhysiologyContraction Lines of OwenMFDS Part 1

Histological examination of a ground tooth section shows broad, dark, arcuate incremental markings within primary dentine. They run approximately parallel to the dentino-enamel junction and are more pronounced than the regular fine incremental lines of von Ebner. Which process most likely produced these contour lines of Owen?

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Reveal the answer and explanation

Correct answer: B — Systemic physiological stress disrupting dentine formation during dentinogenesis

Explanation lettering: E = shown as A · A = shown as B · B = shown as C · C = shown as D · D = shown as E

The correct answer is A. Contour lines of Owen are accentuated incremental lines in primary dentine caused by a transient disturbance of dentine matrix deposition or mineralisation during dentinogenesis. They may record systemic physiological stress such as significant illness or metabolic disturbance. Normal daily rhythmic dentine deposition produces the much finer incremental lines of von Ebner, so B is incorrect. Trauma or pulpal infection after eruption may stimulate tertiary dentine, including reactionary or reparative dentine, rather than create contour lines throughout previously forming primary dentine; therefore C and E are incorrect. Fluoride exposure is principally associated with developmental enamel changes and is not the defining cause of contour lines of Owen, excluding D.

Reference: Austin C et al. Stress exposure histories revealed by biochemical changes along accentuated lines in teeth. Journal of Archaeological Science: Reports. 2023. https://pubmed.ncbi.nlm.nih.gov/37054846/