Effect of Ceramic Surface Treatment on Bonding to Inceram Alumina

Statement of problem: The enhancements of restorative materials combined with the search for esthetics has increased the applications of ceramic restorations. However, the effects of different cement and surface treatment combinations are still unknown.

Purpose: This study evaluated, through in vitro shear strength tests, the bond between different cements and a densely sintered aluminum oxide ceramic, with and without airborne-particle abrasion.

Material and methods: 50 squares (5x5x1mm) of InCeram Alumina (Vita InCeram 2000 AL CUBES) were made. Half of them were abraded with 50µm Al2O3 (type A), and the other half remained untreated (type B). The complete sample was then divided into 5 subgroups, according to the type of cement that was dispensed over its surfaces through a cylinder with 2mm. G1: MaxCem (Kerr), G2: Multi Link (Ivoclar Vivadent), G3: RelyX Luting 2 (3M), G4: RelyX Unicem (3M), G5: RelyX Arc (3M). Each subgroup had 5 type-A and 5 type-B specimens. All specimens were tested under shear loading until fracture on a universal testing machine. The data was statistically analyzed by an ANOVA F-test of equality of means.

Results: The mean and standard deviations (SD) in megaPascal were: Group1A=4.6(±3); Group1B=1.1(±2.4); Group2A=3.4(±1.7); Group2B=1.5(±1.1); Group3A=1.2(±0.8); Group3B=1.1(±1.5); Group4A=7.6(±4.4); Group4B=2.2(±0.5); Group5A=2,1(±0.8); Group5B=1.2(±0.5). The mean of TypeA was 3.8(±3.3) significantly greater than that of TypeB 1.4(±1.4) (p=0.0023). Statistical evidence suggests that the type of cement has a clear effect on the results within the TypeA specimens (p = 0.008), but is inconclusive when applied on TypeB.

Conclusions: Within the scope of this study, we conclude that air-particle abrasion is efficient in enhancing the resistance of all ceramic restorations to shear force. The cement which presented the best results was the RelyX Unicem (3M).