Morphologic assessment of dental surface/ glass ionomer cement interface: influence of Er:YAG laser pretreatment

Introduction and objective: The aim of this study was to assess the surface and the substrate/glass ionomer cement (GIC) interface after Er:YAG laser irradiation by means of scanning electron microcopy. Material and methods: Thirty human third molars were selected and had their roots removed. Crowns were sectioned to obtain discs that were randomly assigned to three groups according to the surface pretreatment: 40% polyacrylic acid (control); Er:YAG laser irradiation (80mJ/2Hz) or Er:YAG laser followed by 40% polyacrylic acid. Two discs of each group were put aside to the surface analysis and the others were bisected. One half received Ketac-Fil and the other received Fuji II LC. Specimens were prepared for SEM and were analyzed under different magnifications. Results: Er:YAG laser group showed no adhesive interface for both enamel and dentin, but strongly damaged the interface build-up for dentin/Fuji II LC. The application of laser irradiation followed by the polyacrylic acid exhibited gaps and irregularities for both substrates. Conclusion: Er:YAG laser irradiation combined or not with 40% polyacrylic acid produced a surface unfavorable for GIC interaction, especially for the resin-modified ones.