The Bacteriostasis Activity Of Ag^nano To Enterococcus Faecalis And Its Biofilm

Objective: To study the bacteriostasis activity of Ag^nano（nano-silver）toEnterococcus faecalis as well as its biofilm （stabled and starved stage） and comparewith that of calcium hydroxide （pH=12）.Methods:1.Three study groups [1%Ag^nano,2%Ag^nanoand calcium hydroxide （pH=12）]were used to Enterococcus faecalis for2h,4h,6h,8h,10h,24h and48h. The activity ofEnterococcus faecalis was evaluated by MTT method.2.The biofilm of stabled and starved Enterococcus faecalis was constructed oncover glass. The bacteriostasis activity of study groups were appraised by colonycounting method at4h,8h,12h,24h and48h.Results:1. To free Enterococcus faecalis （108cfu/ml）, all three study groups started toinhibit the bacterials since the first two hours. Ag^nanohad strong bacteriostasis activityamong these seven time points.2%Ag^nanocan kill the bacterials. While1%Ag^nanoandcalcium hydroxide （pH=12） can inhibit the growth of Enterococcus faecalis. During thewhole process, the effect of Ag^nanois better than that of calcium hydroxide （pH=12）（p<0.05）.2. All three study groups can inhibit the biofilm of stabled and starvedEnterococcus faecalis. The bacterial number decreased since the first study time point（4h）. The peak was at12h. Then the decrease number got small. At4h、8h and12h, the2%Ag^nanogroup inhibited much more bacterial than1%Ag^nanogroup （p<0.05） andcalcium hydroxide （pH=12）（p<0.05）. Conclusions:1.2%Ag^nanocan kill the free Enterococcus faecalis （108cfu/ml） and1%Ag^nanoaswell as calcium hydroxide （pH=12） can inhibit them. The performance of1%Ag^nanowas better than calcium hydroxide （pH=12）.2. Ag^nanoand calcium hydroxide （pH=12） can inhibit the growth of Enterococcusfaecalis’ stabled and starved biofilm. The2%Ag^nanowas the best one. Calciumhydroxide （pH=12） can only inhibit part of bacterials.