A mussel glue-inspired monomer-etchant cocktail for improving dentine bonding

Highlights

Objectives

The humid oral environment adversely affects the interaction between a functionalized primer and dentine collagen after acid-etching. The robust adhesion of marine mussels to their wet substrates instigates the quest for a strategy that improves the longevity of resin-dentine bonds. In the present study, an etching strategy based on the incorporation of biomimetic dopamine methacrylamide (DMA) as a functionalized primer into a phosphoric acid etchant was developed. The mechanism and effect of this DMA-containing acid-etching strategy on bond durability were examined.

Methods

Etchants with different concentrations of DMA (1, 3 or 5 mM) were formulated and tested for their demineralization efficacy. The interaction between DMA and dentine collagen, the effect of DMA on collagen stability and the collagenase inhibition capacity of the DMA-containing etchants were evaluated. The effectiveness of this new etching strategy on resin-dentine bond durability was investigated.

Results

All etchants were capable of demineralizing dentine and exposing the collagen matrix. The latter is strongly integrated with DMA via a covalent bond, hydrogen bond, and Van der Waals’ forces. These interactions significantly improve collagen stability and inhibited collagenase activity. Application of the etchant containing 5 mM DMA achieved the most durable bonding interface.

Conclusion

Dopamine methacrylamide interacts with dentine collagen in a humid environment and improves collagen stability. The monomer effectively inactivates collagenase activity. Acid-etching with 5 mM DMA-containing phosphoric acid has the potential to prolong the longevity of bonded dental restorations without compromising clinical operation time.

Clinical Significance

The use of 5 mM dopamine methacrylamide-containing phosphoric acid for etching dentine does not require an additional clinical step and has the potential to improve the adhesive performance of bonded dental restorations.