ABSTRACT
Oral Streptococci especially Streptococcus mutans are the major cause of dental caries and periodontal diseases. Going along with the increasing antibiotic resistance of bacteria, new methods for decreasing of oral cavity pathogens must be investigated. The aim of this study was to determine the effect of lactobacillus fermentum ATCC9338 as a probiotic strain on the adhesion of oral streptococci to the surfaces. S. mutans ATCC35668 with oral streptococci isolated from dental plaque and caries [40 isolates] were studied. The ability of biofilm formation was investigated using the colorimetric method. An isolates showing the strongest activity in forming biofilm were selected. Then the effect of probiotic strain on the adhesion of the selected isolate to the polystyrene microtiter plate was determined simultaneously and 30 minutes before streptococci entrance to the system. This study showed that in the presence of probiotic strain, the streptococcal adhesion were reduced, and this reduction was significantly stronger if the probiotic strain was inoculated to the system before the oral bacteria. Adhesion reduction is likely due to bacterial interactions and colonization of adhesion sites with probiotic strain before the presence of streptococci. Adhesion reduction can be an effective way on decreasing cariogenic potential of oral streptococci