Inhibition of Streptococcus mutans adherence by means of surface hydrophilization

Derivatives of polyalkylene oxide (PAO) were examined for their ability to inhibit adherence of 3H-labeled cells of Streptococcus mutans to hydroxyapatite (HA) and to plastic surfaces treated with buffer or parotid saliva from two individuals. Pellicles formed on HA with saliva from the two subjects were distinct in their binding capacity. One saliva promoted and the other saliva reduced adherence, as compared with the buffer control (BHA). Three of the PAO compounds effectively hindered binding of bacteria to BHA. However, on saliva-treated HA (SHA) the inhibition was not as effective. One compound, a phosphated polypropylene glycol, was potent in inhibiting adherence both to BHA and to the plastic surfaces treated with either buffer or saliva. However, treatment of HA with this compound followed by saliva incubation only gave a limited reduction in the number of bacteria binding. Evidently, salivary constituents are capable of interacting also with the PAO-treated surface. When 14C-labeled hydrophilizing agent was used, it was shown that the PAO was not replaced by salivary molecules. Instead, the components of the saliva that mediate the binding of bacteria seemed capable of adhering directly to the PAO layer.