Effectiveness in root canal disinfection and biocompatibility of a final in vitro irrigation protocol based on...

To evaluate the antimicrobial capacity and cell viability of a final irrigation protocol based on the use of a hydrolases enzymes mixture (HEM) and a hyperosmotic solution (HS) as an alternative to conventional protocols.

Root canals from 28 human first molars were used to develop multispecies anaerobic biofilms in standard reactors and irrigated with various protocols according to the following groups. Group A: control (sterile saline), group B: 2.25 % NaOCl, group C: 1 % NaOCl, group D: HS, group E: 100 U/mL HEM + 1 % NaOCl, group F: 100 U/mL HEM + HS, or group G: 100 U/mL HEM. The disinfection evaluation per group was carried out by CFU counting and Scanning Electron Microscopy (SEM). The viability was determined on fibroblasts.

The F group, which consisted in irrigating with HEM + HS, had a biofilm elimination of over 5.33 (Log reduction), as well as the groups treated with NaOCl with eliminations of up to 5.34 (Log reduction). In addition, the evaluation of viability reflects a biocompatibility of the F group treatment, as opposed to the groups treated with NaOCl.

The irrigation protocols with HEM+HS and HEM+NaOCl turned out to be as efficient as the conventional protocol using NaOCl; moreover, the irrigation protocol with HEM+HS had low cell cytotoxicity in the viability assay when compared to cell cultures exposed to NaOCl.