temperature rise induced by light curing unit can shorten enamel acid-etching time

objectives: the aim of this in-vitro study was to assess the thermal effect of light emitting diode (led) light curing unit on the enamel etching time. materials and methods: three treatment groups with 15 enamel specimens each were used in this study: g1: fifteen seconds of etching, g2: five seconds of etching, g3: five seconds of etching plus led light irradiation (simultaneously). the micro shear bond strength (µsbs) of composite resin to enamel was measured. results: the mean µsbs values ± standard deviation were 51.28±2.35, 40.47±2.75 and 50.00±2.59 mpa in groups 1, 2 and 3, respectively. there was a significant difference between groups 1 and 2 (p=0.013) and between groups 2 and 3 (p=0.032) in this respect, while there was no difference between groups 1 and 3 (p=0.932). conclusion: simultaneous application of phosphoric acid gel over enamel surface and light irradiation using a led light curing unit decreased enamel etching time to five seconds without compromising the µsbs.