The antimicrobial efficacy of 'MGP' gutta-percha in vitro

Aim: To determine whether 'MGP' gutta-percha (Westport, CT, USA), a commercially available gutta-percha containing iodoform, inhibits the growth of potential endodontic pathogens. Methodology: Inocula of Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Streptococcus sanguis, Fusobacteriurn nucleatum and Actinomyces odontolyticus were spread onto the surface of agar plates. 'MGP' gutta-percha cones presoaked in sterile water were transferred to the inoculated agar and incubated at 37°C aerobically or anaerobically as required for optimal growth. Identical studies were performed using iodoform-free gutta-percha and sterile paper disks saturated with 10% povidone-iodine. Following incubation, zones of inhibition around the 'MGP' gutta-percha, iodoform-free gutta-percha and disks were evaluated. Results: Povidone-iodine inhibited all the strains. Iodoform-free gutta-percha inhibited S. sanguis and A. odontolyticus. 'MGP' gutta-percha inhibited S. aureus, S. sanguis, A. odontolyticus and F. nucleatum. Neither iodoform-free gutta-percha nor 'MGP' gutta-percha inhibited growth of E. faecalis, E. coli or P. aeruginosa. Conclusions: Compared to iodoform-free guttapercha, iodoform-containing 'MGP' gutta-percha had an inhibitory effect in vitro on S. aureus and F. nucleatum, but not on E. faecalis, E. coli or P. aeruginosa.