Introduction Endogenous dentin matrix metalloproteinases (MMPs) contribute to extracellular collagen matrix degradation in hybrid layers following adhesive dentin bonding procedures. Endodontic irrigants, including chlorhexidine (CHX) and ethylenediaminetetraacetic acid (EDTA) may help protect the hybrid layer from this process. The objective of the present study was to determine the exposure time necessary for EDTA to inactivate endogenous MMP activity in human dentin. Methods Dentin beams (2×1×3 mm) were prepared from mid-coronal dentin of extracted third molars. The beams were demineralized in 10 wt% phosphoric acid which also activated endogenous MMPs, and were divided into four experimental groups based on exposure time to 17% EDTA (0, 1, 2 or 5 min). A generic colorimetric MMP assay measured MMP activity via absorbance at 412 nm. Data were evaluated by Kruskal Wallis ANOVA, followed by Dunn’s pair-wise comparisons at α = 0.05. Results All exposure times resulted in significant inhibition (P<0.001) compared to unexposed controls. Specifically, percent inhibition for 1-, 2-, and 5-minute exposure times were 55.1±21.5%, 72.8±11.7%, and 74.7±19.7%, respectively. Conclusions 17% EDTA significantly inhibits endogenous MMP activity of human dentin within 1–2 min. This may minimize hybrid layer degradation following resin bonding procedures in the root canal space.

No abstract

No abstract

No abstract

The addition of BAK to NaOCl significantly reduced the number of remaining bacteria within the canal after irrigation compared with NaOCl alone.