Method: Thirty human teeth with pulp necrosis and periapical lesion were divided into 3 groups (n=10) according to the auxiliary chemical solution used for biomechanical preparation: G1) 1% sodium hypochlorite; G2) 2% chlorhexidine gel; G3) 12% propolis glycolic extract. Collections were performed in three times: immediately after coronary open (1st), after instrumentation (2nd) and after 14 days with intracanal medication (3rd). For all collections were performed the following tests: microorganisms detection by PCR; assessment of microbiological growth and quantification of endotoxin (Limulus amoebocyte lysate assay). The results were submitted to Kruskal Wallis and Dunn’s test (5%).
Result: The results showed decrease in the amount of microorganisms and endotoxins after the 2nd and 3rd collections compared to the 1st for all irrigation solutions (p>0.05). Root canals showed microbial diversity, but Parvimonas micra was predominant among the other microorganisms studied.
Conclusion: It was concluded that 12% propolis extract showed activity against microrganisms and endotoxins similar to the others auxiliary chemical solutions. Parvimonas micra was the most frequently microorganism detected in root canals of teeth with pulp necrosis and periapical lesion.
Keywords: Antimicrobials, Endodontics, Microbiology, Molecular biology and Teeth