Evaluation of the risk of Enterococcus faecalis cross-contamination of gutta-percha cartridges

Background: Gutta-percha (GP) cartridges are intended for a single patient and are not considered sterile. Providers may use these cartridges in multiple canals of a single tooth or multiple teeth on the same patient without disinfection between uses, creating the potential for bacteria to be transferred between canal systems. Enterococcus faecalis is a hardy bacterial species often isolated from failed root canal treatments. This study tested if GP cartridges have the potential to cross-contaminate root canals with E. faecalis. Methods for GP cartridge disinfection were also evaluated. Methods: Twenty-three–gauge medium-body GP cartridges placed in an obturation unit were purposefully contaminated with 1 of 3 concentrations of E. faecalis strain OG1RF. Contaminated cartridges were either (1) wiped with an alcohol swab, (2) heated with GP extrusion while in the bacterial culture, (3) heated with GP extrusion while in the bacterial culture and then wiped with an alcohol swab, or (4) not disinfected after removal from the bacterial culture (control). Bacteria were dislodged into a fresh medium by sonication, and the number of viable bacteria recovered from the tips was measured. Results: Viable cultures of E. faecalis could not be recovered consistently from tips in the control and disinfection treatment conditions. Conclusions: Cross-contamination of root canals with E. faecalis with the GP cartridge is unlikely.