Suppression of bacterial adherence by experimental root canal sealers

To prevent reinfection after root canal treatment, root filling materials should be antimicrobial. This study assessed the antimicrobial efficacy of KT-308, a modified glass ionomer cement sealer, and three formulations of ZUT, a combination of KT-308 and three different concentrations of a silver-containing zeolite. Discs prepared from the test materials and paper controls were incubated in Brain Heart Infusion broth for 12 wk. At 2-wk intervals, 18 discs from each group were inoculated with Enterococcus faecalis and incubated for periods of 1 to 30 h. After further processing, a 200 microliters aliquot of the broth immersing each disc was plated on agar and assessed for bacterial growth. The remaining broth was measured for optical density. All ZUT discs demonstrated no bacterial growth after 15 h of interaction, in contrast to abundant growth with the KT-308 and paper discs. Thus ZUT effectively suppressed adherent E. faecalis after 15 h, irrespective of its concentration and age.