Adhesion of conventional and self-adhesive resin cements to indirect resin composite using different surface conditioning methods

Abstract

This study evaluated the adhesion of conventional and self-adhesive resin cements to indirect resin composite (IRC) using different surface conditioning methods. Cylindrical IRC specimens (N=192) were randomly assigned to four surface conditioning methods (n=8 per group): (a) Control group, (b) Hydrofluoric acid, (c) Tribochemical silica-coating, and (d) 50m Al2O3 air-abrasion. Specimen surfaces were finished using silicon carbide papers up to 600 grit under water irrigation, rinsed and dried. Direct composite blocks were bonded to IRC specimens using three conventional resin cements (Multilink, Panavia F2.0, and Resicem) and three self-adhesive resin cements (RelyX U100, Gcem, Speed Cem). Specimens were subjected to shear bond strength test in a Universal Testing Machine (0.5mm/min). Failure types were categorized as mixed, adhesive and cohesive. Data were analyzed using 2-way ANOVA and Tukey's tests. Two-parameter Weibull modulus, scale (m) and shape (0) were calculated. The bond strength results (MPa) were significantly affected by the surface conditioning method (p<0.0001) and cement type (p<0.001). For Panavia F2.0, Resicem, air-abrasion with 50m Al2O3 significantly increased the results (22.6 +/- 6.5, 26.2 +/- 6.5, respectively) compared to other conditioning methods (13.6 +/- 1.4-21.9 +/- 3.1) but for Multilink, hydrofluoric acid etching (20.5 +/- 3.5) showed significantly higher results (p<0.01). For the self-adhesive resin cements, air-abrasion with 50m Al2O3 significantly increased the results compared to other conditioning methods, except for RelyX U100 (p<0.05). After air-abrasion with Al2O3, Gcem, (11.64), RelyX U100 (9.05), and SpeedCem (8.29) presented higher Weilbul moduli. Exclusively cohesive failure in the IRC was observed with RelyX U100 and Speedcem after Al2O3 air-abrasion.