Fatigue resistance and failure mode of adhesively restored custom implant zirconia abutments.Clin Oral Implants Res. 2012 Dec; 23(12):1360-8.CO
This study assessed the fatigue resistance and failure mode of porcelain and composite resin crowns and onlays bonded to premolar custom zirconia implant abutments.
MATERIALS AND METHODS
Sixty standardized zirconia implant abutments were milled (NeoShape) according to two different restoration designs (onlay or crown). Using Cerec 3, the corresponding onlays and crowns were fabricated either in ceramic (Paradigm C) or composite resin (Paradigm MZ100), resulting in four experimental groups (n = 15). The fitting surfaces of the abutments were airborne-particle abraded and cleaned. The intaglio surfaces of the restorations were HF-etched and silanated (Paradigm C) or airborne-particle abraded and silanated (Paradigm MZ100). Following insertion of the abutments into a Morse taper implant (Titamax CM), all restorations were bonded with a zirconia primer (Z-Prime Plus), adhesive resin (Optibond FL), and a preheated light curing composite resin (Filtek Z100). Cyclic isometric chewing (5 Hz) was simulated, starting with a load of 50N (5000×), followed by stages of 200N, 400N, 600N, 800N, 1000N, 1200N, and 1400N (25,000× each). Samples were loaded until fracture or to a maximum of 180,000 cycles. The four groups were compared using the life table survival analysis (Logrank test at P = 0.05).
All composite resin onlays and crowns survived (100% survival rate), while ceramic ones fractured at an average load of 1347N and 1280N, respectively, (survival rate of 46.7% and 20%) with a significant difference in survival probability (P < 0.0001). Fractures consisted in partial or total failure of the restoration only (no abutment failure, no screw loosening).
Composite resin onlays and crowns bonded to custom zirconia implant abutments presented a significant higher survival rate when compared to ceramic onlays and crowns.