PATHOGENICITY OF BACTERIA USING A SIMULATED ROOT-CANAL SYSTEM

The purpose of this study was to investigate the reliability of an imp lantation test using Teflon-simulated root canals for evaluating the p athogenicity of root canal bacteria. Models including suspensions of l yophilized strains (Actinomyces israelii, Streptococcus faecalis, and Porphyromonas asacharolyticus) were implanted in rat subcutaneous tiss ue for 1 wk, and histological changes were observed. Severe inflammati on occurred around the models. Among them, P. asaccharolyticus induced the severest inflammatory response. Further study using P. asaccharol yticus was conducted to compare the implantation test's ability to eva luate pathogenicity with that of an injection test at 1, 2, or 4 wk. T issue injected with a bacterial suspension showed no clear response th rough the experimental periods, whereas tissue around implantation sit es showed a severe response at I wk. However, the inflammatory respons e subsided at later stages. Consequently, further improvement is neede d to investigate pathogenicity for long periods.