Gold Onlay Thickness — NDEB AFK MCQ
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Correct answer: D — 1.5 mm
The minimum recommended metal thickness for a cast gold onlay is 1.5 mm on functional (supporting) cusps and 1.0 mm on non-functional cusps. This ensures adequate strength to resist functional forces without distortion or fracture. Gold alloys have excellent physical properties including high ductility, burnishability, wear compatibility with opposing enamel, and long clinical longevity. The preparation must provide adequate occlusal clearance for these thicknesses.
Reference: Shillingburg – Fundamentals of Fixed Prosthodontics, 4th ed., 2012