Effect of dentin etching and chlorhexidine application on metalloproteinase‐mediated collagen degradation

Abstract

Dentin matrix metalloproteinases (MMPs) are involved in collagen degradation of resin-dentin interfaces. This study evaluated if collagen degradation can be prevented by chlorhexidine after different dentin demineralization procedures. Human dentin demineralization was performed with phosphoric acid (PA), EDTA, or acidic monomers (ClearfilSEBond and XENOV). Specimens were stored (24 h, 1 wk or 3 wk) in the presence or absence of chlorhexidine. In half of the groups, active MMP-2 was incorporated into the storing solution. C-terminal telopeptide determination (ICTP) was performed in the supernatants. Collagen degradation was higher in PA and EDTA-demineralized dentin. Chlorhexidine reduced collagen degradation in these groups only for 24 h. When dentin was demineralized with SEBond or Xeno, collagen degradation was reduced up to 30%, but addition of exogenous MMP-2 significantly increased collagen degradation. In self-etchant treated dentin the inhibitory effect of chlorhexidine on MMPs lasted up to 3 wk. Treating dentin with EDTA, PA or self-etching agents produces enough demineralization to permit cleavage of the exposed collagen. Monomers infiltration may exert protection on demineralized collagen, probably through immobilization of MMPs. The partial inhibitory action of CHX on MMP activity produced by self-etching adhesives was prolonged compared to the short-acting in PA or EDTA-treated dentin.

Effect of Phosphoric Acid on the Degradation of Human Dentin Matrix

“…DIscussIOn Osorio et al (2011) were the first to demonstrate that MMP-2 has telopeptidase activity in dentin, although they did not use that term. Using an ICTP-specific ELISA assay, they incubated completely demineralized dentin beams in a medium for 1, 7, or 21 days.…”

“…#HU9655). The only source of ICTP telopeptide fragments in mineralized matrices is attributed to the telopeptidase activity of MMPs (Garnero et al, 1998(Garnero et al, , 2003Osorio et al, 2011). We determined matrix degradation by cysteine cathepsins by measuring the amount of solubilized C-terminal peptide, CTX, in the incubation medium using the Serum CrossLaps ELISA (Immunodiagnostic System, Scottsdale, AZ, USA).…”

“…We determined matrix degradation by MMPs by measuring the quantity of solubilized type I collagen C-terminal cross-linked telopeptides (ICTP) (Garnero et al, 2003;Osorio et al, 2011) over the 3-day incubation periods, using the ICTP ELISA kit (TSZ ELISA, Framingham, MA, USA; Cat. #HU9655).…”

“…An alternative approach is to study the functional activity of matrix-bound MMPs in situ. This approach measures the end results of protease activity by Effect of Phosphoric Acid on the Degradation of Human Dentin Matrix quantifying the rate of solubilization of hydroxyproline-containing peptide fragments (Garnero et al, 1998), or the rate of release of collagen C-terminal telopeptides by cysteine cathepsins and MMPs (CTX and ICTP, respectively), as these proteases slowly degrade the dentin matrix (Garnero et al, 2003;Fedarko et al, 2004;Osorio et al, 2011). The advantage of this indirect approach is that one may assay the total protease activities of the dentin matrix in their natural bound state, and their responses to activators and inhibitors.…”

In-vitro Comparative Study of the use of 2 % Chlorhexidine on Microtensile Bond Strength of Different Dentin Adhesives: A 6 Months Evaluation

“…MMPs can be activated by the simple step of conditioning dentin with phosphoric acid (De Munck et al, 2009). Thus, the use of etch-and-rinse adhesive systems might produce a higher activation of endogenous MMPs in dentin, while in self-etching adhesive systems it is less pronounced (De Munck et al, 2009;Osorio et al, 2011), which can be translated in decreased interface degradation. In our study, this fact was not observed, since the etch-andrinse adhesive system did not show a higher degradation compared to the self-etch adhesive system.…”