Protecting resin-dentin interfaces from hydrolytic and enzymatic degradation is critical for the longevity of adhesive restorations. In recent years, several strategies have been tested in vitro to induce apatite precipitation within interfibrillar and intrafibrillar collagen spaces, as well as in resin-sparse regions where the adhesive infiltration was incomplete. Also, the presence of calcium ions and other metallic ions has shown an inhibitory effect on enzymatic activity. Ion-releasing particles and biomimetic analogs have been studied for hybrid layer remineralization. Overall, remineralization strategy is dependent on the remaining mineral content. In partially demineralized dentin, residual apatite crystallites serve as nucleation sites for calcium and phosphate ions precipitation and crystal growth ("top-down" remineralization). In completely demineralized dentin where crystallites are absent (e.g., acid etched dentin) the use of mineral nano-precursors assisted by non-collagenous proteins analogs are necessary ("bottom-up" remineralization). This article reviews the approaches for hybrid layer remineralization and resin-dentin interface preservation.
Keywords: Adhesion; Collagen; Degradation; Dentin; Remineralization.