An In Vitro Evaluation Of The Antibacterial Effectiveness Of Octenisept On Enterococcus Faecalis

Objective:1.To evaluate the antibacterial effect of Octenisept on Enterococcus faecalis in suspension.2.To evaluate and compare the killing efficiency of different concentrations of Octenisept and NaOCl on Enterococcus faecalis biofilms.3.To evaluate and compare the antibacterial effects of different concentrations of Octenisept and NaOCl on E.faecalis in infected root canals.Methods:1.Two-fold dilution method was used to determine the minimum inhibitory concentration(MIC)and the minimum bactericidal concentration(MBC)of Octenisept and NaOCl against Enterococcus faecalis.2.24-h biofilm model of Enterococcus faecalis were established on 24-well cell culture plates and divided into 7 groups randomly according to the rinsing solution(5.25% NaOCl,2.5% NaOCl,1% NaOCl,100% Octenisept,50% Octenisept,25%Octenisept and 0.9%NaCl),2 plates of each group were respectively added with 2 ml of different irrigant,and the corresponding neutralizing agents were added at 15 s,30 s,1 min,3 min,5 min,10 min,20 min,30 min,and 60 min respectively for different irrigant.After terminating the reaction,1 ml of the mixed liquid was removed and added to a test tube containing 2 ml of BHI liquid medium.After incubation at 37℃for 48 h,10μl of plating solution was taken from each tube,and the growth of each plate was observed after incubation at 37℃for 24 hours.According to the growth condition of each plate,record the time that the irrigants completely inhibited the growth of the bacteria.3.76 single-rooted human teeth infected with E.faecalis for 21 days.Three samples were randomly selected before and after infection to observe the status of bacterial infection in the root canal under SEM.The rest were randomly divided into7 groups(n=10).The teeth of each group were irrigated with 5.25% NaOCl(group A),2.5% NaOCl(group B),1% NaOCl(group C);100% Octenisept(group D),50%Octenisept(group E),25% Octenisept(group F)and 0.9% NaCl(group G)respectively.The numbers of bacteria in root canals of each group were calculated before and after irrigation.SEM was used to observe the removal of bacteria on the inner wall of the root canal after irrigation.Results:1.The MIC value of Octenisept is 0.625%,the MBC value is 2.5%,the MIC value of sodium hypochlorite is 0.025%,and the MBC value is 0.1%.2.5.25% NaOCl,2.5% NaOCl,1% NaOCl,100% Octenisept,50% Octenisept,and 25% Octenisept can completely remove the 24-h biofilm of Enterococcus faecalis in a 24-well plate(ie,the sterilization rate reaches 100%).The time from short to long was: 5.25% NaOCl,100% Octenisept,2.5% NaOCl,50% Octenisept,1% NaOCl,25% Octenisept.The time of 5.25% NaOCl,2.5% NaOCl,100% Octenisept,and 50%Octenisept required for these biofilms was shorter and similar,with no significant difference(P>0.05),and there was a statistically significant difference compared with1% NaOCl and 25% Octenisept(P>0.05).There was no significant difference between the two groups with 1% NaOCl and 25% Octenisept(P>0.05).3.Before the establishment of the root canal infection model,the root canal was cleaned and most of the dentinal tubules were open when observed under the scanning electron microscope.4.The root canal of the sample was observed under scanning electron microscope after the root canal infection model was established.E.faecalis adhered to the inner wall of the root canal to form a biofilm,and some of the bacteria entered the dentinal tubule.5.Root canal irrigation test results are as follows.The number of E.faecalis in root canal in all groups were effectively reduced(P<0.01).The reduction of bacteria in the 7 groups was as follows: A>B>D>C>E>F>G.Group A was significantly more effective than group B~G(P<0.05);Group B showed no significant different compared with group D(P>0.05)and was significantly more effective than the rest groups(P<0.05).Group C showed no significant different compared with group E(P>0.05)and was significantly more effective than the rest groups(P<0.05).6.After irrigation,the SEM observation showed that the irrigants in each grouphad good scavenging effect on the enterococcus faecalis biofilm at the root canal of top 1/3.The removal of bacterial biofilms from the middle 1/3 of the root was general,and the effect of group A was obviously better than that of other groups.The clearance effect between group B and D was similar,but it was better than that of group C and E.The effect of group F was the worst.The effect of each group on the biofilm of E.faecalis 1/3 of the root tip was poor.Conelusion:1.Octenisept has a good bactericidal effect against Enterococcus faecalis in suspension.2.5.25% NaOCl,2.5% NaOCl,100% Octenisept,and 50% Octenisept all can effectively remove the 24 h biofilm of Enterococcus faecalis.3.The entericococcal root canal infection model can be effectively established according to our experimental method.4.The antibacterial ability of 100% Octenisept against Enterococcus faecalis biofilms in the root canal was similar to that of 2.5% NaOCl and better than 1%NaOCl.Results show that 100% Octenisept can effectively eliminated Enterococcus faecalis in the root canal.