Etch-mineralizing treatment to improve dentin bonding

Objectives This study aimed to investigate the effect of etch-mineralizing solution as a dentin treatment agent on dentin bonding. Methods This study designed four kinds of etch-mineralizing solutions (EMs) by adding sodium fluoride in 35% phosphoric acid aqueous solution with four different concentrations (5, 10, 20, and 30 mg/ml), and named F1, F2, F3 and F4, respectively. 35% phosphoric acid gel treatment was the control group. SEM, EDS, FTIR and microhardness tests were performed on the treated dentin. Shear bond strength was measured before and after aging. Nanoleakage was also evaluated. Fracture mode was researched after SBS testing. The antibacterial properties of treated dentin were also investigated through live/dead staining of biofilms. Results The smear layer was removed and mineralization substances were observed on the dentin surface and tubule, and no obvious collagen fibers were observed compared with the control group. FTIR spectrums showed that the ratios of phosphate/collagen on EMs treated dentin surfaces were significantly increased (P < 0.05). F2 group had the highest bonding strength (32.14 ± 7.33 MPa) and microhardness (66.08 ± 10.58), while the control group had the lowest bonding strength (21.81 ± 4.03 MPa) and microhardness (42.34 ± 7.08) (p < 0.05), and excellent bonding strength caused more cohesive fracture. Experimental groups showed less nanoleakage than group C (P < 0.05). Moreover, experimental groups had better antiaging performance and antibacterial properties than the control group (p < 0.05). Conclusion EMs treatment not only improved dentin bonding and antibacterial ability, but also remineralized dentin with autologous mineral elements. Clinical significance The treatment provides a novel therapeutic strategy for obtaining ideal dentin bonding strength and prolonging the longevity of the restoration.