Effect of Light-Curing Method and Cement Activation Mode on Resin Cement Knoop Hardness

Purpose: To evaluate the Knoop hardness (KHN) of the resin cement Enforce activated by chemical/physical mode or physical mode solely; light‐cured directly or through a 1.5 mm thick ceramic disc (HeraCeram) on shade DD2. Materials and Methods: Light‐curing was carried out using a conventional quartz tungsten halogen light (QTH) (XL2500) for 40 seconds at 700 mW/cm2; light‐emitting diodes (LED) (Ultrablue Is) for 40 seconds at 440 mW/cm2; and Xenon plasma arc (PAC) (Apollo 95E) for 3 seconds at 1600 mW/cm2. Bovine incisors had their buccal faces flattened and hybridized. A mold was seated on these surfaces and filled with cement. A disc of the acid‐etched and silanized veneering material was seated over this set for light‐curing. After dry storage (24 hours at 37°C), specimens (n= 10) were sectioned for KHN measurements performed in a microhardness tester (50 gf load for 15 seconds). Data were submitted to ANOVA and Tukey's test (α= 0.05). Results: The highest KHN values were obtained with LED, for both dual‐cured and light‐cured cement. The lowest KHN value was obtained with light‐cured PAC. Light‐curing with QTH resulted in hardness values similar to PAC in dual‐cured groups. Conclusions: Light‐curing through HeraCeram can influence resin cement hardness.