Methods: Three self-adhesive resin cements, Clearfil SA Cement (Kuraray), Maxcem Elite (Kerr) and experimental cement GAM-200 (GC) were used in this study. Ten specimens of each material were prepared in a custom fixture and polished, then the specimens were subjected to 400,000 wear machine cycles to simulate localized wear equipped with a conical stylus tip to simulate localized wear. After the wear challenge, the maximum depth and volume loss were determined using a profilometer. Flexural properties were determined with three-point bending test. Statistical analysis was accomplished (ANOVA and Tukey's test). The surfaces of the worn specimens were observed by laser scanning electron microscopy.
Results: The wear depth ranged from 62.1 to 97.1 μm, and the volumetric loss ranged from 0.032 to 0.077 mm3, with significant differences observed between resin cements. The wear depth and volume of GAM-200 was the smaller than those of the Maxcem. The flexural strengths and elastic modulus ranged from 68.4 to 121.4 MPa and from 4.4 to 6.9 GPa, respectively. A significantly greater flexural strength and higher elastic modulus was found for GAM-200 than the other cements. Morphological differences observed by SEM were dependent on the filler composition and the bonding of filler to the matrix resin.
Conclusions: Based on the results of this study, while there were significant differences in in vitro localized wear rates of the self-adhesive cements tested, it appears that the GAM-200 generated lower localized wear values.