In vivo fracture resistance of implant-supported all-ceramic restorations

Abstract

Statement of problem Because of their specific mechanical properties, all-ceramic restorations demonstrate a lower fracture resistance than ceramic restorations supported by metal substructures. However, advances have been made in the fabrication of high-strength all-ceramic abutments for anterior implants. No previous study has compared the fracture loads between 2 different all-ceramic abutments restored by glass-ceramic crowns. Purpose The purpose of this in vitro investigation was to quantify the fracture load of implanted-supported Al 2O 3 and ZrO 2 abutments restored with glass-ceramic crowns. Material and methods Two ceramic abutments were tested: an Al 2O 3 abutment (CerAdapt) and a ZrO 2 abutment (Wohlwend Innovative). The abutments (n = 10) were placed on Brånemark dental implants and prepared for restoration with glass-ceramic crowns (IPS Empress). After fabrication, in accordance with the manufacturer's guidelines, the crowns were bonded to the all-ceramic abutments with a dual-polymerizing resin luting agent. The fracture loads (N) were determined by force application at an angle of 30 degrees by use of a computer-controlled universal testing device. The data were analyzed with the unpaired t test (α=.05). Results Statistical analysis showed significant differences between both groups ( P=.001) of all-ceramic abutments, with mean fracture load values of 280.1 N (± 103.1) for the Al 2O 3 abutments and 737.6 N (± 245.0) for the ZrO 2 abutments. Conclusion Within the limitations of this study, both all-ceramic abutments exceeded the established values for maximum incisal forces reported in the literature (90 to 370 N). The ZrO 2 abutments were more than twice as resistant to fracture as the Al 2O 3-abutments.