Chlorhexidine application to stabilize the adhesive interface: why and how?

Abstract

Chlorhexidine Application to Stabilize the Adhesive Interface: Why and How ? The stability of the bonded interface relies on the creation of a compact hybrid layer through optimal impregnation of the dentin collagen by resin monomers.3,10,17,18 Unprotected collagen fibrils vulnerable to hydrolytic degradation may be present within the hybrid layer due to incomplete resin impregnation.15 Dentinal endogenous enzymes, named MMPs and cysteine cathepsins, can degrade the exposed collagen fibrils and contribute to aging of the adhesive interface over time.3,10-14,16-18 The application of chlorhexidine has been shown to effectively inhibit these enzymes (particularly MMP-2, -9, and -8, and cysteine cathepsins) and its protective role seems to continue over time.1,2,4-7,9-11 Chlorhexidine application should be performed on etched dentin, in association with etch-and-rinse adhesives, before primer and bonding application.1,2,4-7,9-11 Controversial findings were reported on self-etching adhesives and self-adhesive cements.8,19-21 Despite the fact that self-etching material activates MMPs,14 the role of chlorhexidine in stabilizing the bond in the absence of phosphoric-acid etching should be further investigated. CAUTION: After chlorhexidine application (in water solutions from 0.2% to 2% for at least 30 s), rinsing should be avoided, while dentin must be carefully air dried in accordance with the wet-bonding technique, followed by primer/bonding agent application.