Method: Twenty 10x1x1mm3 specimens were prepared in an opaque Teflon split mold with one of the two resin cements (n=10). They were photo-activated through a “cervical” window with 1x1mm2 (Radii Plus; SDI) for 40 seconds. Measurements of Knoop hardness were performed at three different depths: 2.0mm-“cervical”, 5.0mm-“medium”; and 8mm-“apical” thirds The results (KHN) were statistically analyzed by repeated measures 3-way ANOVA and Tukey test considering the factors Cement, Time, Depth, and their interactions.
Result: There were no significant double and triple interactions. The core-and-post cement (22.2±20.0) showed higher microhardness than conventional cement (16.5±18.0). The microhardness at 21 days (14.5±11.9) was statistically significant lower than 24h (24.2±23.5). The cervical third showed the highest microhardness values (34.2±24.1a), followed by the medium third with intermediary values (16.7±12.7b), and apical third with the lowest values (7.1±2.6c).
Conclusion: The resin cements showed similar behavior with remarkably reduction on KHN values as depth increased.