Adhesion of Streptococcus mutans to salivary proteins in caries-free and caries-susceptible individuals.

Adhesion of microorganisms to dental surfaces is the initial step in the formation of dental bacterial plaque. Streptococcus mutans (S. mutans) is considered the main causal agent of one of the most common diseases in humans: dental caries. Adherence of these bacteria results from the interaction of adhesins that form part of their structure with salivary components, specifically those that compose the acquired pellicle. The complexity of this interaction has been the subject of studies in past years, to the extent of identifying certain salivary components related to adhesion to enamel surfaces, such as proline-rich proteins (PRSs), Staherins, Histatins, Cystatins, etc. One of the objectives of this study was to determine the adhesion capacity of S. mutans to synthetic hydroxyapatite incubated with saliva samples of caries-active and caries-inactive individuals. For the purpose of these assays, both the whole saliva samples and the salivary protein extracts were used. They were obtained by separating the proteins contained in the simple SDS-PAGE, in three ranges of molecular weight, selected in accordance with the electrophoresis profile that was usually found. The results indicated that the adhesion of this microorganism was greater in caries-inactive patients, when tested with whole saliva and proteins in the 120-159 kDa molecular weight range. This suggests that adhesion, per se, does not have a definite effect on the mechanisms that cause the disease in some individuals. However, these are interesting findings that may contribute to the design of strategies to control the adhesion of S. mutans to the tooth's surface.