Antimicrobial Effect Of Bioactive Glass On Carious Bacteria And Supergingival Biofilms In Vitro

Dental plaque is one of the factors that lead to dental caries. Numerous of antimicrobials have been developed to inhibit carious bacteria and plaque. Except traditional antimicrobials, such as fluoride, chlorhexidine and triclosan.Novel biological antimicrobial materials are continuously being reseached and applied.Bioactive glass contains oxides of sodium, calcium, silica and phosphorus, and has some extent of biological activities to cure dentin hypersensitivity and remineralize dental caries. This study aimed to research the antibacterial and antiplaque effect of bioactive glass and compare the utilizations of three antimicrobials or their combinations. The results and mechanisms may provide some evidence of new applications for dental clinics.Part I Sterlized effect of bioactive glass on three oral bacteria and supergingival biofilmsObjective To evaluate the effect of bioactive glass with different concentrations on three planktonic bacteria, single Streptococcus sanguis biofilm and mixed biofilm.Methods Three kinds of bacteria, Streptococcus sanguis, Streptococcus mutans and Actinomyces viscosus were used to determine the Minimal inhibitory concentration(MIC) and Minimal bactericidal concentration(MBC), and the pH value were measured as well. Field emission scanning electron microscope (FE-SEM) was utilized to observe the antibacterial effect of24h Streptococcus sanguis biofilm after10min exposure to37.5,75,150mg/ml bioactive glass. The effect of bioactive glass on24h mixed biofilm were observed under confocal laser scanning microscopy(CLSM).Results The acid-inhibition ability could also be observed at low concentration of bioactive glass, and a significant difference(P<0.001) were found between control and test groups. As the concentration of bioctive glass rised, smaller stacks and thinner layer were visualized via SEM and CLSM.Conclusion Bioactive glass showed a rapid antibacterial effect on plantonic bacteria,single or mixed biofilm.It also showed good sterilization and anti-acid ability under low concentration. Part II Effects of Two Combinations of Bioactive Glass on Early Streptococcus Mutans BiofilmObjective To investigate the antimicrobial effect of bioactive glass with triclosan and sodium fluoride.Methods Put coverlips into plate and incubated with Streptococcus mutans in an anaerobic condition for24h to form a S. mutan biofilm. Test drugs were divide into9groups:1MBC bioactive glass, triclosan and fluoride alone,2MBC bioactive glass, tirclosan and fluoride alone, combination of bioactive glass and triclosan or fluoride, saline. Immerse coverlips into liquid drugs for10min and followed with slightly wash. Use plate counting, scanning electron microscope(SEM) and confocal laser scanning microscopy(CLSM) to analyse the changes in amount and structure of biofilms.Results Plate counting results showed the combination effect is better than use antimicrobials alone. SEM images suggested that the stacks became smaller, bacteria around only left one layer of netted texture. CLSM analysis showed bioactive glass has a good permeation effect, which could help antimicrobials to inactivate the microorganisms in deep.Conclusion BAG treatment with triclosan and NaF has an enhanced antibacterial effect on S. mutans biofilm than BAQ NaF and triclosan treated alone.