Antimicrobial activity of calcium hydroxide pastes on Enterococcus faecalis cultivated in root canal systems.

The effectiveness of calcium hydroxide pastes: Calen and PMCC-Calen associated to chemo-mechanical preparation was assessed on Enterococcus faecalis grown within root canals. Seventy incisors were inserted into TSB medium, sterilized and contaminated with E. faecalis. Culture medium was replaced each 24 h and incubated at 37 degrees C for 72 h. After chemo-mechanical preparation, root canals were filled with Calen or PMCC-Calen (7 or 14 days). Pastes were removed and teeth were inserted into test tubes containing Enterococcosel broth. Calen paste (maintained for 7 and 14 days) induced 70% elimination of enterococci and PMCC-Calen 100% elimination only after maintenance for 14 days. These medications were significantly more effective (p<0.001) than chemo-mechanical protocol alone and PMCC-Calen maintained for 7 days, both incapable to eliminate the viability of enterococci. Calcium hydroxide pastes demonstrated important adjuvant effects in the elimination of enterococci during chemo-mechanical preparation of root canal systems. When associated with PMCC, calcium hydroxide pastes should be maintained for at least 14 days.