RESUMO
INTRODUCTION: The aim of this study is to evaluate the antimicrobial activity of hypochlorite solutions and reciprocating instrumentation associated with photodynamic therapy (PDT). METHODS: One hundred and thirty two root canals were enlarged up to #35 K-file and inoculated with E.faecalis for 14 days. The 132 samples were randomly divided into eleven groups (n = 12) and subjected to the following protocols: G1-distilled water + Reciproc R40 (control), G2-1% sodium hypochlorite (NaOCl) + Reciproc R40, G3-2.5% NaOCl + Reciproc R40; G4-1% calcium hypochlorite (Ca[OCl]2) + Reciproc R40, G5-2.5% Ca(OCl)2 + Reciproc R40; G6-PDT; G7-distilled water + Reciproc R40 + PDT, G8-1% NaOCl + Reciproc R40 + PDT, G9-2.5% NaOCl + Reciproc R40 + PDT; G10-1% Ca(OCl)2 + Reciproc R40 + PDT, G11-2.5% Ca(OCl)2 + Reciproc R40 + PDT. The percentage bacterial reduction was checked by counting the colony-forming units (CFUs) in 10 samples of each group. The remaining 2 samples of each group were submitted to scanning electronic microscopy (SEM) to illustrate the effectiveness of the proposed treatments. Data were subjected to one-way ANOVA followed by Tukey's post hoc test (α = 0.05). RESULTS: The greatest ability to promote bacterial reduction was observed in groups 8 (1% NaOCl + R40 + PDT), 9 (2.5% NaOCl + R40 + PDT), 10 (1% Ca[OCl]2 + R40 + PDT), and 11 (2.5% Ca[OCl]2 + R40 + PDT), with no significant difference between them (p < 0.05). CONCLUSIONS: The association of PDT with hypochlorite solutions and reciprocating instrumentation provides effective elimination of E.faecalis.
