A novel dentin bonding scheme based on extrafibrillar demineralization combined with covalent adhesion using a dry-bonding technique

• Published in: Bioactive materials 2021-10, Vol.6 (10), p.3557-3567
• Main Authors: Yu, F., Luo, M.L., Xu, R.C., Huang, L., Yu, H.H., Meng, M., Jia, J.Q., Hu, Z.H., Wu, W.Z., Tay, F.R., Xiao, Y.H., Niu, L.N., Chen, J.H.
• Format: Article
• Language: English
• Subjects: Adhesive; Carboxymethyl chitosan; Collagen; Dentin; Extrafibrillar
• ISSN: 2452-199X; 2452-199X
• DOI: 10.1016/j.bioactmat.2021.03.024

Dentin bonding is a dynamic process that involves the penetration of adhesive resin monomers into the extrafibrillar and intrafibrillar demineralized collagen matrix using a wet-bonding technique. However, adhesive resin monomers lack the capacity to infiltrate the intrafibrillar space, and the excess water that is introduced by the wet-bonding technique remains at the bonding interface. This imperfectly bonded interface is inclined to hydrolytic degradation, severely jeopardizing the longevity of bonded clinical restorations. The present study introduces a dentin bonding scheme based on a dry-bonding technique, combined with the use of extrafibrillar demineralization and a collagen-reactive monomer (CRM)-based adhesive (CBA). Selective extrafibrillar demineralization was achieved using 1-wt% high-molecular weight (MW) carboxymethyl chitosan (CMCS) within a clinically acceptable timeframe to create a less aggressive bonding substance for dentin bonding due to its selectively extrafibrillar demineralization capacity. CMCS demineralization decreased the activation of in situ collagenase, improved the shrinking resistance of demineralized collagen, and thus provided stronger and more durable bonding than traditional phosphoric acid etching. The new dentin bonding scheme that contained CMCS and CBA and used a dry-bonding technique achieved an encouraging dentin bonding strength and durability with low technical sensitivity. This bonding scheme can be used to improve the stability of the resin-dentin interface and foster the longevity of bonded clinical restorations. [Display omitted] •1-wt% CMCS adjusting could form a 1μm partly demineralized zone with interfibrillar minerals in a clinically viable time.•The stability of dentin collagen and bonding could be enhanced by “selective demineralization” with 1-wt% CMCS in 30 s.•A user-friendly adhesion scheme achieved strong dentin bonding strength and durability with a strengthened interface.•A new bonding scheme can be used to improve the bonding interface stability and foster the longevity of restorations.