A comparison of the micro-shear bond strength and failure mode of non-enclosed and mold-enclosed luting cements bonded to metal

: The objective of the study was to compare 1) the mean micro-shear bond strength and 2) failure mode of cements to metals in nonenclosed and mold-enclosed specimens. Specimens were prepared in mold-enclosed and non-enclosed formats from two RMGIC's and a self-adhesive resin-cement. 3-way ANOVA analysis and Tukey post hoc tests were used to compare mean µSBS results (α=0.05). Failure mode was analysed with Pearson's chi-square test (α=0.05). µSBS was significantly affected by the factors substrate and method (p<0.001) but not by material (p=0.077). There was an interaction between substrate, method and material F (2,144)=3.57, p=0.031, and method and material (2,144)=5.86, p=0.004. All mold-enclosed specimens for the three cements bonded to titanium and non-precious metal exhibited higher (p<0.001) mean µSBS than the non-enclosed specimens. Within this study, mold-enclosed specimens exhibited significantly higher (p<0.001) mean µSBS and adhesive failure compared to non-enclosed specimens.