What is the recommended occlusal reduction over the FUNCTIONAL cusps for a monolithic zirconia crown?

Correct answer: D. 1.5 – 2.0 mm

• A. 2.5–3.0 mm is the reduction range for a metal-ceramic or layered restoration, where you must accommodate a coping plus veneering porcelain. Removing this much for monolithic zirconia sacrifices sound tooth structure unnecessarily.
• B. 0.5–1.0 mm is below the manufacturer minimum even for non-functional cusps of monolithic zirconia, and far too thin for the functional cusp.
• C. 3.0–4.0 mm exceeds any full-coverage requirement and would compromise the pulp.
• D. CORRECT. Monolithic zirconia is the most conservative full-coverage ceramic, needing roughly 1.0–1.5 mm over NON-functional cusps and about 1.5–2.0 mm over FUNCTIONAL cusps, where occlusal load is greatest. The functional cusp bevel is what gives the restoration bulk exactly where the stress concentrates.

Note: Manufacturer guidance varies slightly; the widely taught figures are 1.0–1.5 mm non-functional and 1.5–2.0 mm functional. Confirm against your prosthodontics course notes.