Damage and Reliability of Y-TZP after Cementation Surface Treatment

TLDR

Zirconia-based restorations are widely used in prosthetic dentistry, yet their susceptibility to post‑sintering cementation surface treatments remains controversial. The study investigates how grinding and alumina abrasion affect damage modes and reliability of Y‑TZP cores, and addresses the clinical relevance of surface‑treatment protocols before cementation. Monolithic 0.5‑mm Y‑TZP plates were adhesively cemented to dentin‑like composites and subjected to uni‑axial cyclic contact with a tungsten carbide indenter. Grinding or alumina abrasion produced lower‑surface radial fractures and significantly reduced reliability compared to as‑received cores, attributable to cementation‑surface damage.

Abstract

Zirconia-based restorations are widely used in prosthetic dentistry, but their susceptibility to post-sintering cementation surface treatments remains controversial. We hypothesized that grinding (600-grit) and alumina abrasion (50 µm, 5 sec, 0.5 MPa) affect the damage modes and reliability of zirconia core material. Monolithic CAD/CAM-machined and sintered Y-TZP plates (0.5 mm thickness) were adhesively cemented to dentin-like composite substrates. Uni-axial mouth-motion cyclic contact was applied through a tungsten carbide spherical indenter (r = 3.18 mm). Results showed that zirconia core ceramic is vulnerable to lower surface radial fracture after grinding or alumina abrasion, while the as-received control chiefly fractured from load-application surface cone fracture. Significantly lower reliability of ground and alumina-abraded compared with the as-received zirconia core ceramic can be attributed to damage induced on the cementation surface. Clinical relevance concerning surface treatment protocols for zirconia framework materials prior to cementation is addressed.