Effect of flame cleaning of ceramic surface on the bond strength of composite to ceramic

This study tested the hypothesis that flame cleaning of ceramic surface would increase the bond strength of composite to ceramic than pressure-vaporized steam cleaning. Eris and IPS-Empress ceramic blocks were fabricated, polished (control), airborne-particle abraded with 50-microm alumina particle (A), etched with 5% hydrofluoric acid gel for 2 min (E), or treated with a combination of A and E (AE). They were subjected to either steam cleaning for 20 s or flame cleaning over a gas burner for 2 s. Followed by an application of an adhesive resin, a composite was built-up. Twenty micro-tensile test specimens (approximately 0.9 x 0.9 x 16 mm) were obtained from each group and loaded to failure under tensile force using a universal testing machine at a crosshead speed of 0.5 mm min(-1). anova showed statistically significant differences in the mean bond strength by ceramic, surface roughness, and cleaning method (P < 0.0001). The groupings of the mean bond strength were as follows: flame-cleaned > steam-cleaned; IPS-Empress > Eris; and AE > E > A for IPS-Empress and AE > E approximately A for Eris (Duncan's multiple analysis; alpha = 0.05). This in vitro study suggests that mechanical bond of composite to ceramic can be improved with flame cleaning of ceramic surface.