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Post Preparation Shape — NDEB AFK MCQ

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ModerateEndodonticsPost Preparation ShapeNDEB AFK

Which of the following is the ideal cross-sectional shape of a post-preparation in the root canal?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: EAnti-rotational (matching the canal shape — often oval or irregular)

The ideal post-preparation shape should match the natural root canal anatomy to maximise adaptation while conserving dentin. Since most canals are oval or irregular in cross-section (not round), an anti-rotational shape that conforms to the canal provides better retention (resistance to rotation) than a round post in an oval canal. Custom cast posts are adapted to the canal shape perfectly. Prefabricated posts are usually round and may require modification or may not provide anti-rotation in oval canals without additional retention features.

Reference: Shillingburg – Fundamentals of Fixed Prosthodontics, 4th ed., 2012