IADR Abstract Archives
Shear Bond Strength of Layered, Aged Composite Resins
Objectives: The aim of the study is to investigate the interfacial shear bond force between layered composite resins. Composites are often layered clinically, and this study will evaluate the interfacial strength as a function of composition and aging. The null hypothesis is that there are no differences in shear strength between the composite layers.
Methods: Composite were layered to form a single interface that could be evaluated by a shear test on a universal testing machine with a crosshead speed of 1 mm/min. Composites of filler to monomer ratios of 80/20, 70/30, 60/40, and 50/50 were utilized and each ratio was thermocycled for 0, 200 and 2000 cycles. The data were submitted to an analysis of variance (Type-3 testing of two-way ANOVA) and pairs were subjected step-down Bonferroni t- tests.
Results: Statistical analysis revealed that there was a significant effect of ratio and cycles on shear break load (p<.0001). Thus, the null hypothesis is rejected. Specific pairwise differences are shown below. For the first three rows significant differences between ratios were observed. For the last three rows differences in the number of cycles during the thermocyling were observed.
Conclusions: Significant differences were detected as a function of filler to monomer ratio and thermocycling. This could have implications on the clinical stability of these interfaces.
Methods: Composite were layered to form a single interface that could be evaluated by a shear test on a universal testing machine with a crosshead speed of 1 mm/min. Composites of filler to monomer ratios of 80/20, 70/30, 60/40, and 50/50 were utilized and each ratio was thermocycled for 0, 200 and 2000 cycles. The data were submitted to an analysis of variance (Type-3 testing of two-way ANOVA) and pairs were subjected step-down Bonferroni t- tests.
Results: Statistical analysis revealed that there was a significant effect of ratio and cycles on shear break load (p<.0001). Thus, the null hypothesis is rejected. Specific pairwise differences are shown below. For the first three rows significant differences between ratios were observed. For the last three rows differences in the number of cycles during the thermocyling were observed.
Conclusions: Significant differences were detected as a function of filler to monomer ratio and thermocycling. This could have implications on the clinical stability of these interfaces.