Morphological surface analysis and tensile bond strength of the immediate dentin sealing submitted to different temporary cement removal treatments

The aim of this study was to evaluate the morphological surface and the microtensile bond strength (μTBS) of the immediate dentin sealing (IDS) submitted to four different methods for removing temporary cement. Molar teeth received IDS with adhesive system (Adper Scotchbond Multipurpose, 3 M ESPE). Temporary restorations were made with eugenol-free temporary cement (RelyX Temp NE, 3 M ESPE). After the storage (7 days; 37 °C), the samples were submitted to four methods for removing temporary cement: periodontal curette (PC); sodium bicarbonate sandblasting (SB); aluminum oxide sandblasting (AO); and abrasion with diamond bur (DB). The control group (C) received no treatment. The morphological surface analysis (n = 2) and IDS thickness (n = 3) were analyzed using scanning electron microscopy (SEM). Resin composite blocks (Filtek Z250, 3 M ESPE) were produced and cut into sticks (~1 mm²) for μTBS (n = 9). Fracture patterns were analyzed on stereomicroscope and classified as adhesive, mixed, cohesive-dentin or cohesive-resin. Data were submitted to Shapiro-Wilk test and one-way ANOVA followed by Tukey's post hoc test (α = 0.05). PC and SB groups showed the lowest and the highest μTBS values, respectively (ρ < 0.05). The adhesive failure pattern was more frequently observed in all groups. All methods for removing temporary cement promoted morphological surface changes. SB had the best surface morphology and temporary cement removal. IDS thickness showed no significant difference for all groups. The SB method promoted the highest μTBS, removing the temporary cement without jeopardizing the IDS thickness.