Chlorhexidine Preserves Dentin Bond in vitro

Abstract

Loss of hybrid layer integrity compromises resin-dentin bond stability. Matrix metalloproteinases (MMPs) may be partially responsible for hybrid layer degradation. Since chlorhexidine inhibits MMPs, we hypothesized that chlorhexidine would decelerate the loss of resin-dentin bonds. Class I preparations in extracted third molars were sectioned into two halves. One half was customarily restored (etch-and-rinse adhesive/resin composite), and the other was treated with 2% chlorhexidine after being acid-etched before restoration. Specimens were stored in artificial saliva with/without protease inhibitors. Microtensile bond strengths and failure mode distribution under SEM were analyzed immediately after specimens' preparation and 6 months later. With chlorhexidine, significantly better preservation of bond strength was observed after 6 months; protease inhibitors in the storage medium had no effect. Failure analysis showed significantly less failure in the hybrid layer with chlorhexidine, compared with controls after 6 months. In conclusion, this in vitro study suggests that chlorhexidine might be useful for the preservation of dentin bond strength.

Chlorhexidine does not increase immediate bond strength of etch-and-rinse adhesive to caries-affected dentin of primary and permanent teeth

“…Previous studies (13,24) have shown that caries-affected dentin applying the 2% CHX after acid etching, in order to minimize the degradation of resin-dentin bonds, does not negatively influence the immediate bond strength to sound permanent dentin. Similar results were observed in the present study in primary teeth, corroborating the findings of Ricci et al (17).…”

“…Despite the adequate immediate bond strength, in vivo (12) and in vitro (13) studies have revealed that resindentin bonds deteriorate over time. It has been speculated that a decreasing concentration gradient of resin monomer diffusion within the acid-etched dentin, and a subsequent resin elution from hydrolytically unstable polymeric hydrogels within the hybrid layers (14) leave the exposed collagen fibrils susceptible to hydrolytic and enzymatic degradation, mediated by endogenous metalloproteinases (MMPs) (15).…”

“…It has been speculated that a decreasing concentration gradient of resin monomer diffusion within the acid-etched dentin, and a subsequent resin elution from hydrolytically unstable polymeric hydrogels within the hybrid layers (14) leave the exposed collagen fibrils susceptible to hydrolytic and enzymatic degradation, mediated by endogenous metalloproteinases (MMPs) (15). Researchers have demonstrated that chlorhexidine digluconate (CHX) acts as a potent inhibitor of these enzymes (13,16). In addition to minimizing the degradation of resin-dentin bonds, CHX application should not negatively influence the immediate bond strength, which has already been pointed out in literature (13,17).…”

“…Researchers have demonstrated that chlorhexidine digluconate (CHX) acts as a potent inhibitor of these enzymes (13,16). In addition to minimizing the degradation of resin-dentin bonds, CHX application should not negatively influence the immediate bond strength, which has already been pointed out in literature (13,17). However, it is unclear in the literature the effect of CHX in caries-affected dentin (18)(19)(20), especially in primary teeth.…”

Effect of Metalloproteinase Inhibitors on the Microtensile Bond Strength of Composite Resin to Er:YAG Laser-Irradiated Dentin

“…Studies have shown that matrix metalloproteinase (MMP) inhibitors, such as chlorhexidine (CHX) and more recently sodium fluoride (NaF), are able to preserve the structural integrity of the hybrid layer and consequently improve the longevity of restorations (11)(12)(13)(14).…”