Immediate Dentine Sealing: Towards a Surface Science Perspective on an Undercharacterised Adhesive Interface

<b>Background</b>: Immediate Dentine Sealing (IDS) is a well-established adhesive strategy that protects freshly cut dentine and enhances the clinical performance of indirect restorations. While its mechanical benefits are extensively documented, the surface morphology and chemical nature of the sealed dentine, particularly following provisionalisation and reactivation, remain under-characterised. Understanding this bonding substrate is critical for optimising adhesion and long-term outcomes. <b>Methods</b>: This narrative review synthesises the literature on the morphological and chemical features of dentine following IDS, focusing on the distinction between cross-sectional and surface-level characterisation, as well as the analytical techniques employed. <b>Results</b>: Most studies concentrate on internal bond strength and failure analysis, with only a limited subset incorporating surface-sensitive methods such as top-down SEM or optical non-contact profilometry. Quantitative and chemically resolved data on the reactivated dentine surface, the dentine surface after cleaning or abrasion, prior to cementation are scarce, and standardised analytical protocols are lacking. <b>Conclusions</b>: The bonding interface in IDS, namely the reactivated dentine surface, is underexplored. Future research should apply advanced, non-destructive techniques to characterise this clinically relevant substrate and guide the development of adhesive systems tailored to IDS-treated dentine.