The Vitro Study For The Effects Of Chitooligosaccharides On Mutans Streptpcocci

Objectives: The purpose of this study was to evaluate the cariostatic effect of chitooligosaccharide through a series of experiments in vitro, and to provide experimental evidences and theoretical basis for preventing dental caries with chitooligosaccharide.Methods: Streptococcous Mutans group have been chosen as the experimental bacteria. The collected data were analyzed using the SPSS statistical package.(1) A series of in vitro anticarious laboratory studies include inhibition of bacterial growth, acid production, glucan generation and initial adsorption have been carried out.(2) Cell surface hydrophobicity of Streptococcus mutans was evaluated by the method of microbial adhesion to hydrocarbons (MATH). Inhibition of S. mutans adherence to glass surface were measured and the adherence morphology of Streptococcus mutans were observed by using a scan electron microscope(SEM).(3) Enzyme activities of LDH and γ-GT in bacterial solution were detected to determine the integrity of cell wall. A transmission electron microscope(TEM) were used to investigate the structure of Streptococcus mutans' cell wall.(4) Artificial dental plaque were treated by chitooligosaccharide everytwo days and observed under Scan Electron Microscope on the day 1,3,5,7 of artificial plaque formation to investigate the effect of chitooligosaccharide on dental plaque formation.Results:(1) It was found that chitooligosaccharide can inhibit the growth and insoluble polysaccharide (IPS) generation of S. mutans and S.sobrinus, reduce the descending degree of pH in bacterial supernatant.(2)The cell-surface hydrophobicity of Streptococcus mutans ATCC25175 decreased following the increasement of chitooligosaccharide. The chitooligosaccharides may effective to prevent S. mutans adsorption to glass. The inhibition was dose-dependent. The difference of adherent morphology between the chitooligosaccharide and control media was noticeable.(3) The releasing of LDH and y -GT was proved. Transmission Electron Microscope (TEM) observation show that chitooligosaccharides caused extensive cell surface structures alterations, and the cell walls are appreciably decomposed.(4) Chitooligosaccharide could alter the morphology of artificial dental plaque during the plaque formation and inhibit the formation of plaque.Conclusion: It suggested that the chitooligosaccharide has an irreversible destructive effect on the cell walls of the Streptococcus mutans and can inhibit the formation of plaque.Chitooligosaccharide is proved to be an effective anticaries agent. In addition, further researches will be necessary to define its usefulness in this aspect.