Er: YAG LASER IRRADIATION ON DENTIN: FT-RAMAN AND SEM STUDIES

摘要

This study evaluated the molecular and morphological changes on dentin elements after the En: YAG laser irradiation. Six human third molars were selected and the occlusal one-third of the crown was removed. The dentin surface was schematically divided into areas corresponding to four surface treatments groups: Control (Group C): 37% phosphoric acid etching; Group Ⅰ: EnYAG laser 80mJ; Group Ⅱ: En:YAG laser 120mJ; Group Ⅲ: En:YAG laser 180mJ. The characterization was performed by Scanning Electron Microscopy (SEM) and Fourier-Transformed Raman Spectroscopy (FT-Raman) before and after the treatments. A reduction of the relative intensity for the spectra was observed in the Group Ⅱ and Ⅲ samples. The SEM photomicrographies revealed open dentin tubules in the control group specimens. The groups Ⅰ, Ⅱ and Ⅲ presented partially open dentin tubules. SEM images showed that the laser-irradiated dentin surface was not favorable to the diffusion of monomers. The chemical information obtained by Raman spectroscopy showed that higher laser energies (180 mJ) affected more the phosphate, carbonate and the organic components of dentin.