RESUMO
OBJECTIVE: This study determined the effectiveness of five light-curing units (LCUs; four light-emitting diode [LED] and one laser) used on different settings to photo-activate four conventional resin-based composites (RBCs). MATERIALS AND METHODS: A total of 108 RBC specimens were photo-activated in a white Delrin mold representing a mesial-occlusal-distal (MOD) class II restoration in a molar tooth. The proximal boxes were 5 mm deep, and the mesial-distal length was 12 mm. Immediately after photo-curing, the RBC specimens were immersed in a solvent to remove the uncured materials, after which they were photographed and deidentified. A Research Electronic Data Capture survey was created using these images and sent to respondents who blindly assessed the ability of the various LCUs to photo-cure the MOD restorations. RESULTS: There were significant differences in how the five curing lights had cured RBCs. One-way analysis of variance (ANOVA), pairwise t-test, Welch's one-way ANOVA, and Kruskal-Wallis rank test in the blinded survey data showed significant differences between the LED curing lights used for two 10-second cures and the laser curing light used for 1 second, and LED lights at lower settings. CONCLUSION: There was a significant difference in how the curing lights could photo-cure the RBCs used in this study. The laser curing light used for 1 second produced the worst results in all four RBCs. CLINICAL SIGNIFICANCE: When used for 1 second, the laser curing device does not photo-cure conventional RBC materials as well as the LED curing lights used for 10 seconds.