Crown Retention Factors — NDEB AFK MCQ

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ModerateRestorative DentistryCrown Retention FactorsNDEB AFK

Which retentive feature is most important for the long-term success of full-coverage cast metal crowns?

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Correct answer: C — Both adequate preparation height AND controlled taper acting together

The retention of a full-coverage crown depends on the interaction of multiple factors, but the two most critical geometric features are: (1) adequate preparation height (length) — providing sufficient surface area for cement adhesion and resistance to dislodgement along the path of withdrawal; and (2) controlled taper (4-8° total occlusal convergence) — providing near-parallel walls that resist lateral displacement. A short preparation with excessive taper is the weakest combination. Longer preparations can tolerate slightly more taper while maintaining adequate retention.

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