| ObjectiveThe purpose of this study was to compare the surface morphology, structure and chemical composition of enamel and dentin following the Er,Cr:YSGG laser irradiation or bur ablation.MethodsThe labial enamel or dentin surfaces of 24 recently extracted bovine incisor teeth were prepared with bur. Then 12 of them were irradiated with laser energy: enamel of 6 teeth at 2w setting (5.6J/cm2, water75% , air90% ) and dentin of 6 teeth at 2w setting (5.6J/cm2, water55% , air65% ). The morphological changes of enamel and dentin were investigated with scanning microscopy ( SEM). The structural and atomic changes were investigated with x - ray diffraction ( XRD) and electron microprobe analysis of dispersive energy ( EDX). Data were analyzed using paired - samples t test.ResultCraters having rough but clean surfaces and no melting or carbonization were observed in all the samples. Atomic analytical examination showed that the calcium ratio to phosphorus had no significantchanges between the ablated and the irradiated samples ( p > 0. 05 ). The calcium content of enamel irradiated with the laser are higher than that of the ablated ones, but the irradiated dentin had higher calcium content than the ablated dentin ( p < 0. 05 ). Compared to ablated dental surfaces by XRD investigation, the higher crystallinity was found in laser irradiated enamel and dentin.ConclusionThere existed differences in the morphology, structure and atomic composition of dental surfaces between laser irradiation and bur ablation.
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