Elimination Against Enterococcus Faecalis Of Nd: YAP Laser In Root Canals In Vitro

Objective: The purpose of this study was to explore the elimination effect against E.faecalis in root canals by Nd:YAP laser and compare the effect in different exposure time.Besides,when dentists choose irrigation methods in clinic,the conclusion could be referred to.Methods: Forty human extracted premolars which have single root canal were selected.After cleaning and autoclaving,they were contaminated by E.faecalis and incubated for four weeks to become models.Then the models were randomly and averagely divided into five groups and treated as below: Group A: negative control,Group B: treated with Nd:YAP laser(5 sec),Group C: treated with Nd:YAP laser and 3%Na Cl O(5 sec),Group D: treated with Nd:YAP laser(10 sec),Group E: treated with Nd:YAP laser and 3%Na Cl O(10 sec).The specimens from root canals were collected by paper points.The bacterial suspensions were later serial dilutedand plated on tryptic soy agarplates to enumerate the CFUs after forty-eight hours incubation at 37℃in anaerobic conditions.The results were analyzed by SAS 8.02.Results:As with all parts of the root canal in aggregate,the CFUs of the group treated with Nd:YAP laser are significantly lower than the group of negative control(P<0.05).But there was no remarkable difference among the groups treated with Nd:YAP laser of different exposure time(P>0.05).However,the group treated with Nd:YAP laser and 3% Na Cl O irrigation had the best effect of disinfection.Conclusion: The groups that had treated with Nd:YAP laser showed great effect of elimination against biofilm that made of Enterococcus faecalis compared with only using saline irrigation.But the effect in diferent exposure time was similar.Nd:YAP laer with the irrigation by 3% NaClO was the most efficient method in this experiment.