Antimicrobial effect of a modified vanadium chloroperoxidase on Enterococcus faecalis biofilms at root canal pH.

INTRODUCTION: Previous research showed an antimicrobial effect of vanadium chloroperoxidase (VCPO) on in vitro Enterococcus faecalis biofilms. The current study aimed to optimize the use of this enzyme at the root canal pH using a modified VCPO (mVCPO) that was adapted to function at a higher pH and to explore the biocompatibility of mVCPO. METHODS: The activity of the original and modified VCPO was assessed using the monochlorodimedone assay. For antimicrobial assessment, 48-hour biofilms of E. faecalis OS-16 were incubated 5 or 30 minutes with mVCPO, bromide, and hydrogen peroxide, and colony-forming units were determined. A metabolic activity assay was used to evaluate the cytotoxic effect of mVCPO on oral fibroblasts. RESULTS: Reaction products generated by mVCPO at a root canal pH of 7.7 significantly inactivated the biofilm after 5 minutes and even more after 30 minutes (Mann-Whitney U test, P < .05). The mVCPO reaction products showed less cytotoxic effects than control solutions and 0.5% sodium hypochlorite (Kruskal-Wallis test, P < .05). CONCLUSIONS: The incubation of mVCPO in the presence of its substrates with in vitro E. faecalis biofilms showed a significant antimicrobial effect at the root canal pH. Also, cytotoxicity tests showed preliminary biocompatibility. Therefore, an interappointment dressing containing mVCPO could aid in improving current endodontic treatment through continuous and local generation of antimicrobials.

Effect of vanadium chloroperoxidase on Enterococcus faecalis biofilms.

INTRODUCTION: The aim of this study was to explore the antimicrobial effect of vanadium chloroperoxidase (VCPO) reaction products on Enterococcus faecalis biofilms of 4 different strains. METHODS: Twenty-four-hour biofilms of E. faecalis strains V583, ER5/1, E2, and OS-16 were incubated in mixtures with VCPO, halide (either bromide or chloride), and hydrogen peroxide. The antibacterial efficacy was assessed by colony-forming unit counts. RESULTS: The VCPO reaction products had a similar efficacy in reducing the viability of the 4 strains of E. faecalis (94%; range, 87%-100%). Bromide as the halogen of choice was more effective on E. faecalis strains E2 and OS-16, as compared with chloride (Mann-Whitney U test; P < .05). Despite different quantities of produced biofilms by the 4 strains, VCPO treatment was similarly effective toward all strains (Kruskal-Wallis test; P < .05). CONCLUSIONS: VCPO treatment results in an antimicrobial effect toward in vitro E. faecalis biofilms and might provide an addition to current endodontic treatment, possibly as an antimicrobial dressing.