Crown Preparation Taper — NDEB AFK MCQ

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ModerateRestorative DentistryCrown Preparation TaperNDEB AFK

What is the taper angle recommended for the axial walls of a full crown preparation to optimise both retention and cementation?

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

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Correct answer: E — 4-8 degrees total convergence

The recommended total occlusal convergence (TOC) for a full crown preparation is 4-8 degrees (approximately 2-4 degrees per wall). Greater taper reduces retention due to decreased resistance to dislodgement. Less taper makes seating the crown difficult and traps cement. Clinical studies show that most clinicians produce preparations with 12-27 degrees TOC, exceeding the ideal range.

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