The application of mussel-inspired molecule in dentin bonding

To evaluate the effect of dopamine methacrylamide (DMA) pretreatment on resin-dentin bond durability.

Forty acid-etched dentin surfaces were randomly allocated into five groups, and pretreated with one of the primers: 0.1, 1.0, and 10 mmol/L DMA/ dimethyl sulfoxide (DMSO) solutions, pure DMSO, and deionized water (control) before bonding. The bonded teeth of each group were randomly distributed into an immediate subgroup (water storage at 37 °C for 24 h) and an aged subgroup (thermocycling, 5-55 °C, 10,000 times). The teeth were sectioned into 0.9 mm slabs; two middle slabs were used for nanoleakage evaluation, while the remaining slabs were sectioned into beams for micro-tensile bond strength (MTBS) test. Fractured mode and nanoleakage were observed under SEM. FTIR was used to assess the effect of primers on the degree of conversion (DC) of adhesive.

The MTBS was significantly affected by primers (p <  0.001), aging conditions (p <  0.001) and their interactions (p <  0.001) as revealed by two-way ANOVA. Significant increase in nanoleakage was observed in both the aged control and DMSO groups when compared to their immediate values (p <  0.05); while no differences were observed in the aged DMA-treated groups (p >  0.05). Among the three DMA-treated groups, 1.0 mM DMA/DMSO primer manifested the highest MTBS with the lowest nanoleakage after thermocycling aging. Application of 10 mM DMA/DMSO significantly decreased the DC of adhesive (p <  0.05).

The 1.0 mM DMA/DMSO solution is a potential functional primer to enhance the durability of resin-dentin bond.

Sixty seconds pretreatment of 1.0 mM DMA/DMSO solution on dentin surfaces provides dentists an alternative choice to preserve dentin bond strength. Dopamine methacrylamide might strengthen the integrity of hybrid layer by serving as a bridge connecting the demineralized collagen fibrils and adhesive polymer network.