An in vitro test model for investigation of disinfection of dentinal tubules infected with Enterococcus faecalis.

The aim of the present study was to develop an in vitro test model from human teeth to comparatively examine antibacterial effectiveness of calcium hydroxide, parachlorophenol (PCP) and camphorated parachlorophenol (CPCP) against Enterococcus faecalis in infected root canals. Cylindrical dentin specimens were prepared from freshly extracted human maxillary anterior teeth. The specimens were inoculated with E. faecalis and then medicated with either CPCP, PCP or Ca(OH)2. The disinfecting efficacy of these agents was tested by collecting dentin chips from the inner ("canal") walls of the specimens and counting viable E. faecalis. The dentin chips were diluted and a classical bacterial count technique was used for recovery of E. faecalis strains of 5% sheep blood agar. The effectiveness of CPCP and PCP at one day was superior to the effectiveness of Ca(OH)2. In the three-day group, CPCP was the most effective, followed by Ca(OH)2. The experimental model used in this study may be useful for investigation of the effect of intracanal medicaments on microorganisms lodged in the root dentinal tubules.