Purpose: To compare two blue LED (light emitting diode) sources in terms of curing efficacy as determined by the ablation resistance of light-cured composite resins when irradiated with an Er:YAG laser. Materials and Methods: A hybrid composite resin was photocured with two blue LED light sources at 105 mW/cm2 and 1000 mW/cm2. Composite tablets were photocured for two different irradiation times: 5 s and 40 s. A focused Er:YAG laser at five energy levels per pulse (100 to 500 mJ), a fixed frequency of 10 Hz, and water flow of 0.46 ml/s, was used for 10 s to ablate the cured composite resin. Results: The obtained values were plotted to allow a comparative observation of the removed material volume as a function of fluence. The higher the energy per pulse, the higher the ablation rate; however, above 300 mJ, the photocuring time and LED intensity were important factors influencing curing efficacy. Conclusions: The lowest intensity parameter allowed the largest ablation rate on material photocured for 5 s, while the highest intensity produced the same result on material photocured for 40 s.

Keywords: photocuring, composite resins, LED, laser, Er:YAG, ablation rate