Microshear bond strength according to dentin cleansing methods before recementation

ABSTRACT

PURPOSE: The aim of this study was to determine the efficiency of Erbium, Chromium Yttrium-Scandium-Gallium-Garnet laser in different output powers for removing permanent resin cement residues and therefore its influence on microshear bond strength compared to other cleaning methods. MATERIALS AND METHODS: 90 extracted human molars were sectioned in 1 mm thickness. Resin cement was applied to surface of sliced teeth. After the removal of initial cement, 6 test groups were prepared by various dentin surface treatment methods as follows no treatment (Group 1), ethylene diamine tetra acetic acid application (Group 2), Endosolv R application (Group 3), 1.25 W Erbium, ChromiumYttrium-Scandium-Gallium-Garnet laser irradiation (Group 4), 2 W Erbium, ChromiumYttrium-Scandium-Gallium-Garnet laser irradiation (Group 5) and 3.5 W Erbium, ChromiumYttrium-Scandium-Gallium-Garnet laser irradiation (Group 6). The topography and morphology of the treated dentin surfaces were investigated by scanning electron microscopy (n=2 for each group). Following the repetitive cementation, microshear bond strength between dentin and cement (n=26 in per group) were measured with universal testing machine and the data were analyzed by Kruskal Wallis H Test with Bonferroni correction (P<.05). Fracture patterns were investigated by light microscope. RESULTS: Mean microshear bond strength +/- SD (MPa) for each group was 34.9 +/- 17.7, 32.1 +/- 15.8, 37.8 +/- 19.3, 31.3 +/- 12.7, 44.4 +/- 13.6, 40.2 +/- 13.2 respectively. Group 5 showed significantly difference from Group 1, Group 2 and Group 4. Also, Group 6 was found statistically different from Group 4. CONCLUSION: 2 W and 3.5 W Erbium, Chromium Yttrium-Scandium-Gallium-Garnet laser application were found efficient in removing resin residues.