Effects of Surface Treatment and Dental Preparation on the Fracture and Debonding of High-Translucency Zirconia Occlusal Veneers.

Objective: Different surface treatments and dental preparations for the fracture and debonding of high-translucency zirconia occlusal veneers were evaluated.

Methods: Occlusal veneers were divided into four groups (A1, A2, B1, and B2), which differed in surface treatments and tooth preparation designs (A1: Partially wrapped + sandblasting; A2: Partially wrapped + lithium disilicate coating; B1: Partially wrapped with box-shaped + sandblasting; B2: Partially wrapped with box-shaped + lithium disilicate coating). All veneers were uniformly bonded to the tooth resin model. The fracture strengths of the veneers and adhesive surface were examined. The data were analyzed via multifactor analysis of variance.

Results: No interaction effect was found between preparation design and surface treatment on occlusal veneers fracture load (F = 0.43, p = 0.51). Surface treatment alone significantly affected occlusal fracture load (p < 0.05), while preparation design did not (p > 0.05). However, their interaction significantly impacted bond interface fracture load (F = 9.69, p = 0.00), with both factors independently showing significant effects (p < 0.05).

Conclusion: Dental preparation did not affect the fracture load of high-translucency zirconia veneers but did affect the fracture load of the bonding surface of high-translucency zirconia veneers. Compared with the surface treatments, the surface-applied lithium disilicate coating increased the strength of the restoration itself and the bonding strength of the bonding surface.

Clinical significance: Combining the preparation with box-shaped retention and a lithium disilicate coating could be used as a beneficial repair option to improve the anticracking and disbonding ability of high-translucency zirconia occlusal veneers.