A Comparison Between the Durability of Glass-Ceramic and Translucent Zirconia Veneers: A Randomized, Split-Mouth, Controlled Trial with 5 Years Follow-up

This clinical study aimed to evaluate the bonding strength of multi-shaded zirconia veneers to resin cement compared to glass-ceramic veneers over a five-year observation period. The study sample consisted of 15 cases (30 veneers), with each case including one glass-ceramic veneer and one multi-shaded zirconia veneer. The veneers were applied to five patients (four females and one male) on the maxillary anterior teeth, with both types of veneers applied sequentially. The teeth were prepared using an overlapped incisal preparation technique for both types. Zirconia veneers were subjected to air abrasion (sandblasting) followed by the application of a zirconia primer (Z-Prime Plus), whereas glass-ceramic veneers were treated with hydrofluoric acid and a dual silane coupling agent. All veneers were bonded using a light-cured resin cement. The clinical monitoring revealed a survival rate of 93.3% for zirconia veneers compared to a 100% survival rate for glass-ceramic veneers over the five-year observation period. Air abrasion of the internal surface of zirconia veneers using aluminum oxide particles, followed by the application of a zirconia-specific primer containing 10-MDP, significantly enhanced the bond strength of resin cement to zirconia. This bonding strength was comparable to that achieved with glass-ceramic veneers, using the overlapped incisal preparation technique for both veneer types.