Maximum Load to Fracture of Various Resin Cements to Densely Sintered Aluminum Oxide

Abstract Objective: Aluminum oxide cannot be altered by acid etching, yet it is claimed that resin cements may be bonded to the surface. The purpose of this in vitro study was to evaluate the maximum load to fracture of several commonly used resin cements to densely sintered aluminum oxide. Methods: Sixty specimens of densely sintered aluminum oxide (Procera®) 10x10x4mm were fabricated so that one side of the sample replicated the pressed portion of the coping. The samples were etched and bonding agent applied according to the manufacturer’s specification. Rely X-arc (3M), VariolinkII(Vivadent), Nexus(Kerr), PermaFlo(Ultradent), Choice(Bisco), LinkMax(GC America) were dispensed using a standard mold to develop a consistent bonding area of 2.379mm for testing. The cements were light cured and stored for 24 hours. A shear load was applied at the junction of the ceramic samples and the cement with a knife-edge rod at a crosshead speed of 0.5mm/min in a Universal testing machine. The maximum load to fracture data from all samples was then analyzed using 2-way Anova. Results: The highest maximum load to fracture was obtained with VariolinkII. There was no statistically significant difference between VariolinkII and Choice (P=0.05). The mean maximum load to fracture of each cement was as follows: PermaFlo 24.623 MPa, LinkMax 26.372 MPa, Rely-X arc 29.438 MPa, Nexus 29.526 MPa, Choice 31.83 MPa, Variolink 43.601MPa. Conclusion: Variolink II exhibited the highest maximum load to fracture when used with densely sintered aluminum oxide. Supported by Nobel Biocare /University of Michigan Center for Excellence.