Prosthodontics & Occlusion · patient case question
Which crown material is most appropriate for this patient?
Patient case: Bruxist requiring a posterior crown and a splint
Patient: Adult with established parafunction
Chief complaint: Requires a crown; already wears a hard occlusal splint.
Background: Long-standing bruxism. Wears a hard acrylic splint nightly.
Current findings: Generalised occlusal wear. The splint is presented for review.
Show answer and explanation
Correct answer: D. Monolithic zirconia
- A. Feldspathic porcelain is the weakest option (roughly 60–100 MPa) and is contraindicated in parafunction.
- B. Layered lithium disilicate has the same weakness — the veneer chips. Monolithic lithium disilicate (around 400 MPa) is reasonable but still weaker than zirconia.
- C. PFM with a porcelain occlusal surface leaves the vulnerable veneer bearing the load. PFM with a METAL occlusal surface would be a strong alternative, but the porcelain-occluding version is not.
- D. MONOLITHIC ZIRCONIA offers the highest flexural strength (roughly 900–1200 MPa) with no weak veneering layer to chip. In a heavy bruxist, the failure mode that matters is cohesive fracture of veneering porcelain, and a monolithic restoration eliminates it entirely.
Note: Note the trade-off: monolithic zirconia is strong but abrasive to opposing enamel, and must be well polished after any adjustment.
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