The Preliminary Study On The Effect Of Tannic Acid Against Streptococcus Mutans

Dental caries is an oral disease caused by many complicated factors and thebacterium is one of the most important factors. Streptococcus mutans is the maincariogenic bacteria in oral disease, following by lactobacillus and actinomycetes.Furthermore, Streptococcus mutans has the most significant relationship with dental caries,which also plays an important role in the early biofilm formation. In the absence of thebacteria occurred, the dental caries must rely on this particular biofilm formation.Therefore, one of the effective measures for prevention of dental caries is to control theplaque biofilm formation and against the cariogenic bacteria such as Streptococcus mutans.Nowadays, chlorhexidine and fluoride are regarded as the effective antibacterial agentagainst cairiogenic bacteria. Nonetheless, there are some limitations among them. The long term use could cause the oral flora disturbance, taste bitter, colored the teeth andsome other adverse reactions. Therefore, searching for a safe and natural anticaries drughas become the focus of caries research.Many herbs such as phellodendron, coptis, honeysuckle, scutellaria root and gallachinensis could against the cariogenic bacteria and the adverse effect is relatively small.The Chinese nutgall has a long history that tannic acid is the main component, which hasthe antibacterial, antioxidant, convergence of bleeding and other biological effects. Theapplication of Galla chinensis in stomatology can effectively inhibit cariogenic bacteriaand promote enamel remineralization and the prevention of periodontitis.In this study, to determine the antibacterial effect of tannic acid on Streptococcusmutans by some experimental researches and to observe its effect on the formation ofStreptococcus mutans biofilm under shear stress, as well as the dental material surface andinterface of plaque biofilm formation. We may provide laboratory basis for its furtherclinical application in stomatology, suggesting that it may act as a new natural drug forclinical application of dental caries.1. In vitro study of tannic acid on Streptococcus mutans and biofilmformationIn this experiment, we determine the minimum inhibitory concentration (MIC) andminimum bactericidal concentration (MBC) of the tannic acid and chlorhexidine againstStreptococcus mutans. According to the results, tannic acid in subsequent experimentsconcentrations were set as8mg/ml and16mg/ml. The control group uses0.2%chlorhexidine (CHX), which commonly used as mouthwash slobber. The bactericidalcurves of different action time can be seen the result of16mg/ml tannic acid withinstantaneous sterilization effect was close to0.2%chlorhexidine. To culture theStreptococcus mutans biofilm under shear stress using Bioflux system, we observe that0.2%chlorhexidine group and two tannic acid groups were no formation of plaque biofilmcompared with the control group. The chlorhexidine group was almost the dead bacteria inscattered. The tannic acid groups can only be observed in a small amount of dead bacteria and live bacteria. Nevertheless, both of them have the same role in inhibiting theformation of early plaque biofilm.2. Effect of tannic acid on the dental material surface and interface ofthe plaque biofilm formationFirstly, the electron microscope was used to observe the Streptococcus mutans on theenamel, dentin under the role of experimental groups. To determine the viable percentageon resin, glass ionomer and porcelain surface of the experimental group after the treatmentof Streptococcus mutans biofilm, we use confocal laser scanning microscopy. The resultshowed that tannic acid groups on the essence and the interface of enamel tooth have notformate the Streptococcus mutans plaque biofilm, and was also observed themorphological changes. The live or dead bacteria of each experimental group wereobserved by laser scanning confocal microscopy. The living bacteria percentage washandled by statistical analysis. There was significant difference between each two ofgroups; the same group of three materials was no statistical difference.