Abstract
This study evaluated the immediate effects of halogen, LED (light-emitting diode), and plasma arc curing units on microleakage of bleached enamel. The buccal and lingual enamel surfaces of experimental groups (n=30) were bleached with 16% carbamide peroxide for a period of 10 days, with a daily contact time of 90 minutes. Box-shaped Class V cavities were also prepared on 60 extracted molar teeth (n=30, control group). For all groups, a composite resin (Grandio) was bonded with one of the two employed adhesive systems, Single Bond 2 or Prime & Bond NT. After restoration, all specimens were thermocycled for 200 cycles between 5°C and 55°C with a dwell time of 60 seconds in each bath, and then exposed to a dye. In the control groups, microleakage was statistically lower than the bleached groups (p<0.01). Groups cured with QTH and PAC showed no statistical differences (p>0.05). However, groups cured with LED system showed statistically significant differences (p<0.01) in microleakage
