RESUMO
The aim of this study was to determine the in vitro antimicrobial effect of six endodontic sealers after 2, 20 and 40 days. The sealers studied were Apexit, Endion, AH26, AH-Plus. Procosol and Ketac Endo. The microorganisms used were Candida albicans, Staphylococcus aureus, Streptococcus mutans and Actinomyces israelii. Petri dishes were filled with sterile agar and 0.1-ml wells were prepared and filled with the sealers. The agar plates were stored for 24 h at 37 degrees C. The samples were then removed, immersed in 4.5 ml of culture medium and divided into three groups. The samples in group 1 were stored for 2 days at 37 degrees C whereas the samples of groups 2 and 3 were stored at 4 degrees C for 20 and 40 days respectively. The samples were then removed and discarded, and 0.1 ml of the culture medium was seeded on the agar plates in order to perform colony forming unit counts. Apexit, Endion and AH-Plus produced slight inhibition on Streptococcus mutans at 20 days and on Actinomyces israelii at every time interval. No effect was found on Candida albicans and Staphylococcus aureus. Ketac Endo only produced an antimicrobial effect on Actinomyces israelii at 2 and 40 days. AH26 and Procosol showed antimicrobial effect at 40 days on Candida albicans, at 20 and 40 days on Streptococcus mutans and Staphylococcus aureus, and an effective inhibition on Actinomyces israelii at every time interval. Statistical analysis revealed both sealers and microorganisms to be significant factors affecting results in groups 2 and 3. In conclusion, the sealers evaluated in this study showed different inhibitory effects depending on time span. Overall, sealers containing cugenol and formaldehyde proved to be most effective against the microorganisms at the time intervals studied.