Study on the adsorption of Streptococcus mutans to platinum electrodes.

Abstract

Abstract:The object of this study aimed to investigate the adsorptive properties of a cariogenic Streptococcus mutans including six serotypes and a non-oral bacillus Escherichia coli using an apparatus designed for the measurement of bacterial adsorption to electrostatically charged platinum electrodes in vitrc. Quantitative estimation of the bacterial adsorption by electron microscopy and the conditions affecting the bacterial adsorption to platinum electrodes were examined . Morphological differences in the materials adsorbed to the platinum electrodes which had been inserted into a human oral cavity were also examined as an in vivo experimental system.The bacterial cells used were adsorbed more abundantly to positive electrodes than to negative electrodes. The number of S. mutans strain HS6 (serotype a) adsorbed to the positive electrodes increased with bacterial concentrations and current intensities up to 300uA. The bacterial adsorption to the positive electrodes was promoted by heating the bacterial cells and pretreatment of the electrodes with whole saliva. The bacterial cells of S. mutans adsorbed on the positive electrode were desorbed with time from this surface, when the polarity was changed . Scanning electron microscopy showed that in the human mouth the quantity of materials adsorbed on the positive electrodes placed was larger than those on the negative.Results otained from in vitro and in vivo experiments strongly suggest that adsorption of the cariogenic bacterium S. mutans to positively charged surfaces of restorative materials or tooth surfaces may play a role in producing the dental plaque associated with dental caries and periodontal disease .