Observation On The Dentinal Tubular Invasion Of Enterococcus Faecalis By Confocal Laser Scanning Microscope

Objective:Establish an in vitro root canal model infected by Enterococcus faecalis, observing on the dentine tubular invasion and the effect of calcium hydroxide by CLSM. To discover the regularities of distribution of Enterococcus faecalis in dentine tubular and initially value the efficacy of calcium hydroxide through the viability state of bacterium.Method:(1) Established an in vitro infected root canal model for 28days, and identified with fluorescence microscope or CLSM. (2) respectively taking the infective sample in 1,2,3,5,7days, observing the distribution and viability state of Enterococcus faecalis in dentine tubular. (3) after incubation for 28days, calcium hydroxide and sterile water were applied to infected root canal model. The specimens were taken in time intervals ranging froml to 7days and observed by CLSM.Results:(1) Enterococcus faecalis were seen clearly under fluorescence microscope or CLSM; the later one did a better job. (2) After 3days incubation, Enterococcus faecalis were detected in dentine tubular, the infection rate and depth of invasion were increasing with the time goes by, showing the statistic significantly (P<0.05). the maxim depth in group of 7days can reach 174-222μm. percentage of viable bacterium in 5μm near entrance of tubular is significantly higher than it in the whole field(P<0.05). (3) Along with the effective time of medicament, the extent of disinfection was increasing, and it over 562μm after 7days intervene.Conclusion:CLSM is appropriate to detect viability of Enterococcus faecalis in infected dentin, to explore its regularities of distribution, as well as to value the medicament.