Antibacterial Effect Of Bioactive Glass On Three Species Of Bacteria And Sub Gingival Bacterial Plaque In Vitro

Periodontal disease is one of the most common oral diseases among humans which happens to be the primary cause of tooth loss in adults. Bacteria of the dental plaque biofilms and their products are the initial trigger factors leading to periodontal disease.How to restrain the formation of plaque and remove it is an important issue for controlling periodontal disease.Bioactive glass(BG) was invented in 1969 by professor Hench, composed of Si O2 and Na2 O, Ca O, P2O5. Bioactive glass has the effects of sealing dentin tubules, treating dentin hypersensitivity, and it can also be the substitute material for bone.Bioactive glass has also shown a broad antibacterial effect.But,for the study of antibacterial effect of bioglass on plaque, especially the subgingival plaque causing periodontal disease,there is not much data.This experiment is intended to explore the ability of bioactive glass to restrain and kill three kinds of bacteria.And we simulated three kinds of single bacteria plaques and the subgingival early mixed plaque in vitro to explore the antibacterial effect of bioactive glass aganist the plaques.The aim of this study is also to compare the antibacterial effect of bioactive glass and inorganic antibacterial agent chlorine,explore the efficacy of bioactive glass, and provide the basis for clinical application.Part I Antibacterial effect of Bioactive glass on three species of bacteriaObjective To evaluate the effect of bioactive glass with different concentrations on three planktonic bacteria and biofilms and to compare the susceptibility of the two different types of bacteria to bioactive glass.Methods Three kinds of planktonic bacteria, Streptococcus sanguis, Actinobacillus actinomycetemcomitans and Fusobacterium nucleatum were used to determin E the Minimal inhibitory concentration(MIC) and Minimal bactericidal concentration(MBC). The single species biofilms of the three bacteria formed on slides were used to assess the minimal biofilm eradication concentration(MBEC) to bioactive glass.Results Low concentration of bioactive glass showed an antibacterial and sterilized effect.The MBECs of BG to single species of biofilms were significantly greater than the MICs and MBCs of planktonic bacteria. MBECs were 2 ~ 16 times than MICs.Conclusions Bioactive glass can inhibit and kill planktonic forms of Streptococcus sanguinis, Actinobacillus actinomycetemcomitans and Fusobacterium nucleatum as well as the single species of biofilms. However the effect on single species of biofilms was much better.Part II Antibacterial effect of bioactive glass for 24 h early subgingival mixed plaque by confocal laser scanning microscoyObjective To evaluate the effect of bioactive glass with different concentrations on 24h early subgingival mixed plaque formed by three kinds of bacteria.Methods 20, 40, 80 mg/ml of bioactive glass and inert silica glass(Si O2) were used on 24 h early mixed bacterial plaque. Confocal laser scanning microscopy(CLSM) was used to observe and analyze the thickness and average fluorescence intensity of the plaque.Results With the increasing bioglass concentrations, there was a relative decrease in the thickness, mass and vitality of the mixed plaque. Statistically there was a significant difference between the blank control group and Si O2 groups(P < 0.05).Conclusions Bioactive glass has A certain antibacterial effect on the early subgingival mixed plaque. The higher the concentration,the better the antibacterial effect.Part III Comparing the antibacterial effect of bioactive glass to Chlorhexidine on Actinobacillus actinomycetemcomitansObjective To compare the antibacterial effect of bioactive glass to Chlorhexidine on Actinobacillus actinomycetemcomitans.Methods Minimal inhibitory concentration(MIC), Minimal bactericidal concentration(MBC) and the minimal biofilm eradication concentration(MBEC) to Actinobacillus actinomycetemcomitans were assessed by bioactive glass and Chlorhexidine. Actinobacillus actinomycetemcomitans biofilms were dealt with bioactive glass and Chlorhexidine for 10 min, with the the concentration of 1/2MBEC and 1MBEC,and observe the activity of bacteria by Plate counting.Results MBECs of bioactive glass and Chlorhexidine were higher than the MICs and MBCs of planktonic forms of Actinobacillus actinomycetemcomitans.MBECs were 4 to 8 times of respective MICs. Plate counting results showed significant difference(<0.05)between bioactive glass and Chlorhexidine in 1MBEC group,and the bacteria L activity w AS lower in the group treated by bioactive glass.No statistical difference was found in 1/2MBEC group.Conclusions Low concentration of bioactive glass and Chlorhexidine can have an antibacterial effect on Actinobacillus actinomycetemcomitans. Bioactive glass showed much better effect than Chlorhexidine.