Temperature changes and hardness of resin-based composites light-cured with laser diode or light-emitting diode curing lights.

Abstract

The temperature and Vickers Hardness (VH) at the top and bottom surfaces of three resin-based composites (RBCs) were measured when light-cured using five light-curing units (LCUs). The spectrum, power, and energy delivered to the top of the RBCs and transmitted through the RBCs were measured. Starting at 32℃, the temperature rise produced by the Monet Laser (ML-1s and 3s), Valo Grand (VG-3s and 10s), DeepCure (DC-10s), PowerCure, (PC-3s and 10s) and PinkWave (PW-10s) were measured at the bottom of specimens 2mm deep × 6mm wide made of Filtek Universal A2, Tetric Evoceram A2 and an experimental RBC codenamed Transcend UB. The VH values measured at the top and bottom of these RBCs were analyzed using ANOVA and Scheffe's post hoc test (p < 0.05) to determine the effects of the LCUs on the RBCs. The transmitted power from the ML was reduced by 77.4% through 2mm of Filtek Universal, whereas light from PW decreased by only 36.8% through Transcend. The highest temperature increases from the LCU combined with the exothermic reaction occurred for Transcend, and overall, no significant differences were detected between Filtek Universal and Tetric Evoceram (p = 0.9756). Transcend achieved the highest VH values at the top and bottom surfaces. The PinkWave used for 10s produced the largest temperature increase (20.2℃) in Transcend. The Monet used for 1s produced the smallest increase (7.8℃) and the lowest bottom:top VH ratios.