The Effects of Different Surface Preparation Techniques on Enamel Surface Properties and Bond Strength

The purpose of this study was to investigate the morphological and chemical changes and bond strength on enamel surfaces subjected to different surface preparation techniques. Two different settings of Er:YAG laser and air-polishing systems were used to prepare the enamel surfaces besides the conventional acid application. The samples were evaluated in in vitro tests with 7 different groups (acid etching, Er:YAG laser quantum square pulse(QSP) mode, and Er:YAG laser medium-short pulse(MSP) mode at 10Hz,1.2W,120mJ, Air-Flow, and its combination with acid). Surface profilometer and AFM were used to evaluate the surface roughness of the specimens. After the surface treatment, the chemical changes that occured on enamel were analyzed using SEM-EDS. The effects of preparation technique on the bond strength to the enamel surface were evaluated by using micro tensile and shear bond strength tests. The values obtained the surface roughness evaluation of surface profilometer and AFM were compatible with each other. The highest roughness value was found in QSP when all groups were compared. Ca/P ratios of the surfaces were evaluated as a result of SEM-EDS analysis and it was observed that Ca/P ratio increased in all groups except Acid. It was seen that the results obtained for all groups of micro tensile and shear bond strength tests were consistent with each other. The highest values were observed in QSP+Acid, while the lowest values were observed in Air-Flow. In conclusion, it is considered the use of Er:YAG laser QSP settings with acid can effect the long-term success of restorations clinically.