Resin bonding to Er : YAG laser-irradiated dentin: combined effects of pre-treatments with citric acid and glutaraldehyde

The purpose of this study was to evaluate the combined effects or citric ac id and glutaraldehyde (GA) on the resin bonding to Er: YAG laser-irradiated dentin. Bovine dentin was prepared with 180- to 600-grit SiC paper and the n uniformly irradiated with an Er: YAG laser (laser-irradiated group) or im mersed in water at 60 degreesC for 15 min (heated group). The samples were then acid-conditioned with 10% citric acid (10-0) or 10% citric acid/3% fer ric chloride (10-3) for 15 s and treated with GA for 10 min before bonding to an acrylic rod with 4-META/MMA-TBB resin. These samples were trimmed to prepare miniaturized dumbbell-shaped specimens. After storage in water at 3 7 degreesC for I d, the tensile bond strength was measured, and the fractur ed surface was evaluated using a scanning electron microscope (SEM). In the laser-irradiated and heated groups, the 10-3+GA-treated specimen had highe r bond strength than that of 10-0+GA. On the other hand, the tensile bond s trength of 10-3+GA in the non-irradiated group was lower that that of 10-0GA. In conclusion, the combination of 10-3 and GA for bonding with 4-META/M MA-TBB resin was the most effective for Er: YAG laser-irradiated dentin and heated dentin, but it was not effective for tile non-irradiated dentin.