Structural reliability and bonding performance of resin luting agents to dentin and enamel

Abstract This study evaluated the bonding performance and structural reliability of indirect resin composite restorations luted to dentin and enamel. Four resin luting agents were tested in the study, namely three total-etch materials (Allcem; Allcem Core; and RelyX ARC) and one self-adhesive material (RelyX U200). The materials were characterized with degree of conversion (DC) and pH analyses, and used to lute resin composite restorations to dentin or enamel (n = 6). The restorations were prepared for microtensile bond strength (μTBS) testing (DL500). Data were analyzed with ANOVA or Kruskal-Wallis and Tukey/SNK (α = 0.05). Weibull analysis was used to verify the structural reliability and characteristic strength of dental bonds. While RelyX ARC exhibited greater DC, RelyX U200 was the most acidic material of the study. Allcem and RelyX U200 demonstrated greater and lower μTBS, respectively, at both dentin and enamel. Comparing μTBS of dentin and enamel, RelyX ARC and RelyX U200 produced higher bonds in dentin. RelyX U200 showed ~100% of adhesive failures, differing from other groups. Structural reliability was higher for Allcem Core in dentin and for RelyX U200 in enamel; the characteristic strength was higher for Allcem and lower for RelyX U200. Conventional resin luting agents performed better than the self-adhesive material, at both dentin and enamel. Among the conventional materials, Allcem demonstrated an overall greater bonding ability and lower probability to failure. DC and pH of resin luting agents did not influence on their bonding performance.