Abstract
Aim: The purpose of this study was to analyze and compare the micromorphology of the hybrid layer and the dentinal surface when the dentin was prepared with an Er:YAG laser or burs, and to find if there was any difference if the time of application of the self-etching primer on the dentin prepared with an Er:YAG laser was doubled.
Materials and methods: Fifteen freshly extracted human teeth with preserved crowns were selected. Three cavities were prepared on each extracted tooth. Two of the cavities were prepared with an Er:YAG dental laser, and the third with burs. A self-etching adhesive system was applied. The primer of the adhesive was labeled with Rhodamine B, and the bond was labeled with fluorescein prior to application. The teeth were sectioned mesiodistally through the cavities and the cavity of each sample was examined using a confocal laser scanning microscope. The infiltration and micromorphology were determined qualitatively on ninety samples.
Results: The dentinal surface in the samples prepared with burs was smoother and with shorter resin tags than the surface prepared with an Er:YAG laser. When using an Er:YAG laser for preparation, crater-like irregularities of the surface were observed. In five of the samples prepared with burs, no resin tags were found. We could not detect any difference in the hybrid layer when the time of application of the adhesive system was increased.
Conclusions: The clinical significance of the tag length and quality, as well as the infiltration ratio, needs to be further studied.