Chlorhexidine Inhibits the Proteolytic Activity of Root and Coronal Carious Dentin in vitro

Abstract

The purpose of this study was to evaluate the effect of chlorhexidine on the proteolytic activity of carious coronal and root dentin collected from patients. Sound dentin from freshly extracted human teeth was used as a control. Dentin fragments were mixed with a synthetic substrate for proteolytic enzymes (N-benzoyl-DL-arginine-naphthylamide – BANA) and the suspensions mixed with either 0.12% chlorhexidine digluconate or distilled water. These mixtures were incubated for 18 h at 37°C, color was developed by the addition of 0.1% Fast Garnet and their optical density was recorded spectrophotometrically. BANA hydrolysis measured by the optical density of incubated specimens was detected in all tested groups, but was significantly higher for carious than for sound dentin (p < 0.05). The proteolytic activity was reduced for carious coronal and root dentin by chlorhexidine (p < 0.05; 50 and 30%, respectively). Chlorhexidine also reduced the proteolytic activity in sound root dentin (p < 0.05; 20%). Conversely, changes in the proteolytic activity of sound coronal dentin were not observed in the presence of chlorhexidine. The reduction in proteolytic activity by chlorhexidine was significantly higher in carious coronal dentin than in carious root dentin (p < 0.05). In conclusion, part of the effect of chlorhexidine in controlling caries progression in humans may be due to a decrease in the proteolytic activity of carious coronal and root dentin. Because of the prolonged incubation time in the present study, similar results may be obtained clinically with prolonged dentin exposure to chlorhexidine, e.g. chlorhexidine-containing varnishes.

<I>In vitro</I> effect of hesperidin on root dentin collagen and de/re-mineralization

“…In previous studies using collagenase, the proteolytic degradation of demineralized matrix was said to enhance the susceptibility of dentin lesions to acid-dependent demineralization 32,33) . Recent studies have demonstrated that CHX possesses a potent anti-proteolytic effect due to its ability to inhibit activity of MMPs in carious dentin 16) . The present study demonstrated a positive effect of CHX in preserving dentin collagen against bacterial proteolysis, which contributed to the low value of organic matrix degradation.…”

“…Pharmacological studies have reported that MMPs activity was reduced by the application of chlorhexidine (CHX) which in turn leads to the arrest of carious lesion 16,17) . Natural products have been used as folk medicine for thousands of years and are promising sources for novel therapeutic agents 18) .…”

Ecological Hypothesis of Dentin and Root Caries

“…MMP inhibitors, such as nonantimicrobial chemically modified tetracyclines and 2-(imidazole-1-yl)-1-hydroxyethane-1,1-bisphosphonic acid (zoledronate), inhibited caries progression in rats [Tjäderhane et al, 1999;Sulkala et al, 2001]. Other reagents, including chlorhexidine [Pashley et al, 2004;Garcia et al, 2009], fluoride [Kato et al, 2014], silver diamine fluoride [Mei et al, 2012], doxycycline [Osorio et al, 2011], ethylene diamine tetraacetic acid [Thompson et al, 2012], benzalkonium chloride [Tezvergil-Mutluay et al, 2011b], quaternary ammonium compounds [Tezvergil-Mutluay et al, 2011a], various metal ions such as zinc [Toledano et al, 2012] and iron [Kato et al, 2010], and natural substances [Chaussain-Miller et al, 2006] have been reported to inhibit host proteases such as MMPs and cathepsins in vitro. Recently, hesperidin was reported to reduce the degradation of human dentin matrix (acid-demineralized dentin) in situ [van Strijp et al, 2015].…”

Dentin Bonding: Can We Make it Last?

“…[70][71][72][73] Several in vitro [74][75][76][77][78][79][80][81][82][83] and in vivo [84][85][86][87] studies have demonstrated that chlorhexidine preserves resin-dentin bonds by eliminating or at least delaying collagen degradation in the hybrid layer ( Figure 3). …”