Ação antimicrobiana de solução à base de polihexametileno biguanida no tratamento endodôntico.

Abstract

The purpose of this study was to compare the antibacterial efficacy of 0,2% polyhexamethylene biguanide solution (PHMB) and 2% chlorhexidine (CHX) as irrigants against Enterococcus faecalis (E.F) infecting root canals. Fifty distal roots of mandibular human molars were selected and randomly placed in the following groups: PHMB (N=20), CHX (N=20), positive control (N=5) and negative control (N=5). With the exception of negative control, the roots were inoculated with E. faecalis (ATCC 29212) in BHI broth. The teeth were incubated under 370C for 4 weeks and fresh BHI broth was replaced every week to ensure bacterial viability. Canals were rinsed with 1mL sterile 0.9% saline solution to remove unattached cells, and samples were collected by using paper points sequentially at the working length, before (S1) and after (S2) chemomechanical preparation. All bacteriological sample collection were submitted to quantification by culture. The instrument WaveOne Gold Large (45/.05) (Dentsply Maillefer, Ballaigues, Switzerland) was used to instrumentation. The irrigants solutions were delivered by using a 30-gauge needle between each instrument change, with a total of 3mL used per canal. After preparation, S2 followed the same pattern as in S1. Qualitatively, PHMB resulted in all cases with negative culture in S2 (100%). The CHlx group also succeded in significantly reducing E. faecalis levels, however only one tooth still had detectable bacteria in S2. It could be observed that 0.2% PHMB solution was highly effective in reducing E. faecalis. PHMB was able to reduce to zero the bacterial counts, even having a 0.2% concentration, with results as 2% chlorhexidine.