Antibacterial Effectiveness Of Diode Laser On Enterococcus Faecalis Within Root Canals In Vitro Evaluation

Purpose : To provide evidence for clinical application of laser in root canal disinfection,this experiment established a model of Enterococcus faecalis infection and observed the comparison of antimicrobial effects of diode laser and traditional root canal irrigation materials on Enterococcus faecalis.Materials and methods:100 freshly permanent teeth with single root canal extracted from human were immersed in the suspension of Enterococcus faecalis to establish the root canal model of Enterococcus faecalis infection.Then,100 isolated root canals infected with enterococcus faecalis were randomly divided into five groups: group A(treated with diode laser),group B(rinsed with 2% chlorhexidine solution),group C(rinsed with 17%EDTA+5.25%Na Cl O solution),group D(treated with diode laser +17%EDTA+5.25%Na Cl O solution)and group E(rinsed with 0.9% normal saline).Colony-forming units(CFU)were measured from the beginning to end of treatment in each group.Then,two samples were randomly selected from each group to cleave longitudinally,and the inner wall of root canal was observed by scanning electron microscopy.Results:Counting results showed that group A,B,C and D had better germicidal effects than group E(p<0.05).What’s more,Group D had the best germicidal effects.The decrease of colony-forming units in group D was significantly higher than that in group A,group B,group C and group E,while that in group A and group C was similar,better than that in group B,and group E was the worst.The differences between group D and other groups have statistical significanc(p<0.05).The results of Electron Microscope scanning showed that the combination of diodes laser and17%EDTA+5.25%Na Cl O,opening of dentinal tubules and smooth inner wall of root canal have a good effect on root canal disinfection.Conclusion: The combination of diodes laser+17%EDTA+5.25%Na Cl O can inhibit the growth and reproduction of Enterococcus faecalis.It has a good effect on root canal treatment and can significantly reduce the number of colonies.The decreasing of colonies is superior to the traditional clinical irrigation treatment.Thus it is worthy being popularized and applied.