In vitro antimicrobial effect of chlorhexidine-impregnated gutta percha points on Enterococcus faecalis

Aim: To evaluate the in vitro antimicrobial effect of chlorhexidine- impregnated gutta percha points, Roeko activpoint (Roeko, Langenau, Germany) on Enterococcus faecalis. Methodology: Human maxillary premolar roots were prepared with .04 rotary ProFile instruments to a master apical file size 40, autoclave-sterilized and then infected with E. faecalis (ATCC 29212) for 3 weeks. Baseline controls were carried out verifying negligible effects of plain gutta percha cones on E. faecalis. Subsequent to intracanal placement of calcium hydroxide, 'activ points' or saline (positive control) and the 2-week incubation in 54 root specimens, dentine sampling at depths of 100 and 250 μm was carried out using .04 rotary ProFile instruments at sizes 60 and 90 to assess the quantity of bacteria present. Inactivating agents were used prior to sampling and the colony-forming units (CFU) of E. faecalis were then plate-counted after culturing. Statistical analysis was completed using the paired t-test. Results: In comparison to the positive control, treatment with calcium hydroxide (P = 0.000 and 0.000) or activ points (P = 0.000 and 0.002) produced significantly lower colony counts of E. faecalis at dentine depths of 100 and 250 μm, respectively. Calcium hydroxide (2.10 x 10² CFU mL^-1) was significantly more effective than activ points (1.58 x 10³ CFU mL^-1) at 100 μm (P = 0.013), but not at 250 μm (P = 0.353). Neither of these two medications was able to eliminate E. faecalis completely. Conclusions Chlorhexidine-impregnated activ points did not possess an in vitro inhibitory activity strong enough to eliminate E. faecalis completely from infected dentinal tubules.