ANTIBACTERIAL ACTIVITY OF POTENTIAL RETROGRADE ROOT FILLING MATERIALS

The antibacterial activity of potential retrograde root filling materi als was assessed using the agar diffusion inhibitory test. A light-cur ed glass ionomer cement (Vitrebond and three reinforced zinc oxide-eug enol cements (Kalzinol, IRM & ethoxybenzoic acid [EBA] cement) were co mpared with amalgam, a commonly used retrograde root filling material. Forty standardized pellets of each material were produced. Fresh, and materials aged for 1 week in sterile distilled water, were placed on blood agar plates inoculated with Streptococcus anginosus (milleri) or Enterococcus faecalis. At intervals of 3, 7 and 10 days, the presence and diameter of zones of inhibition were recorded. The diameter of th e zones of inhibition increased with time for all materials, both fres h and aged. Vitrebond had the most pronounced antibacterial activity a gainst both bacteria, producing the largest zone of inhibition, follow ed by Kalzinol. Amalgam had no measurable inhibitory effect whether ag ed or fresh, regardless of the period of exposure. There was no statis tically significant difference in the response of the two bacteria. Ho wever, there were statistically significant differences between materi als, period of exposure, and between fresh and aged materials (P<0.001 ). Kalzinol, IRM and EBA cement were more antibacterial when aged than fresh, whilst Vitrebond was more active when fresh. Vitrebond was the only material for which the diameter of the zones of inhibition was r educed after ageing but it had the most pronounced antibacterial activ ity compared with the other materials. The antibacterial activity of t he materials was ranked in the following order: Vitrebond > Kalzinol > (IRM = EBA cement) > amalgam.