Influence of surface modification protocols on the bond strength of universal adhesives to amalgam-affected dentin

The aim of this study was to investigate the bond strength of resin composites to the dentin surface after the removal of amalgam restorations. The dentin surfaces of amalgam-removed molars were subjected to different surface treatments (n=45). Following ortho-phosphoric acid, sandblasting, and Er:YAG laser the samples were divided into 3 subgroups, and samples were formed using different universal adhesives (Solare Universal Bond, Gluma Bond Universal, Scotchbond Universal Plus) and nanohybrid composites (G-aenial A'CHORD, Charisma Topaz, Filtek Z550). The microshear bond strength (µSBS) was measured in each group, and the data were statistically analysed via one-way analysis of variance (ANOVA) and Tukey's post-hoc test. The 3M subgroup (39.91 MPa) had the highest bond strength on the laser-treated dentin surfaces, whereas the lowest value was measured in the Kulzer subgroup (3.61 MPa) on the sandblasted dentin surfaces. Composite resin adhesion to amalgam-contaminated dentin surfaces with surface modifications, especially laser treatment, yielded successful results.