V. Angeloni's research while affiliated with University of Bologna and other places

... Resin monomers in adhesives can create microporosities below and inside the hybrid layer, as a result of limited diffusion, incomplete displacement of water and infiltration of the interfibrillar spaces, thus resulting in water-filled gaps within the unprotected collagen fibrils that cause hydrolytic degradation over time [1,4]. Furthermore, host-derived matrix metalloproteinases (MMPs) and cysteine cathepsins (CTs) that are activated by the acid etching process and/or by the acidic pH produced by cariogenic bacteria, also play a relevant role on degradation of the hybrid layer [3,4,[6][7][8][9]. Thus, in order to increase the durability of the adhesive/dentin interface without compromising the mechanical properties of the adhesive layer, bioactive nanoparticles have been considered a promising approach due to their small size, which can combine better infiltration and high surface area to interact with or release ions [10]. ...

... Cross-linking agents have gained significant attention as an innovative approach to inhibiting MMPs and enhancing the longevity of resin-dentin bonds. These agents work by promoting the formation of additional chemical bonds within the dentin matrix [55]. The process involves creating covalent links between collagen molecules, effectively reinforcing the collagen network. ...

... Subsequently, a dental bonding strategy was proposed to physically separate dental collagen from exogenous infectious agents and to fix dental prostheses made of composite resin, metal, or zirconia. During this process, the adhesive resin can penetrate the dentin collagen network and wrap it with collagen fibrils through micromechanical interlocking, ensuring a strong connection between the restoration and the dental tissues (Breschi et al., 2018). ...

... This is recommended to inhibit matrix metalloproteinases, as the durability of the bond can be further compromised by the proteolytic action of these enzymes [33]. The reported effects of chlorhexidine (CHX) pretreatment of dentin on the longevity of the bond between a fiber post and dentin are controversial, ranging from positive and non-significant to detrimental [21,33,34]. In the present study, the application of chlorhexidine (CHX) after EDTA did not significantly improve bond strength. ...

... For this purpose, the application of a cross-linking agent, 1-ethyl-3-(3-dimethylamino-propyl) carbodiimide (EDC), on demineralized dentin was proposed [15]. Indeed, promising results in preserving bond-strength values and inhibiting MMP activity were reported when EDC was applied on coronal dentin during adhesive procedures [17][18][19][20]. EDC was shown to preserve the bond-strength values, cross-link the collagen and silence MMP activity within coronal dentin, even after 5 years of artificial aging, when EAR or SE adhesives were used during adhesive protocols [21]. ...

... These endogenous enzymes can be activated by low-pH acids such as phosphoric acid, which is often used during the etching process of teeth, or by low-pH acids included in self-etch adhesive systems. Moreover, other intrinsic enzymes are involved in addition to MMPs [35]. Active MMPs support the breakdown of unprotected collagen fibrillar structures and are instrumental in the degradation of the hybrid layer that develops over time [36]. ...

... In this study, EDC when used as dentin biomodifier preserved the bond strength even after 6 months storage in artificial saliva. Our results are supported by various studies which reported improvement in resin-dentin bond durability with EDC pre-treatment [17,24,25]. EDC causes stiffening of collagen making it more difficult for MMPs to unwind the collagen triple-helix structure. ...

... Specifically, amide bonds, facilitated by EDC/NHS, are formed between carboxylic acids and amine groups locally available from side chains of collagen polypeptides. This crosslinker was able to produce an inhibition of endogenous enzymes as well as an improvement in the mechanical properties of dentin when used for longer treatment time [12,13]. A recent study further has shown high interfacial bond strengths between two materials (dentin and adhesive) and low activity of endogenous enzyme following storage of samples treated with EDC primer for 5 years [14]. ...

... The restorations were then polished with an abrasive disc using a slow-speed micromotor straight handpiece right after the final curing. Group II and Group III followed the same restorative procedure, except for the change in the primer used 17 . ...