Adhesion of Streptococcus mutans on remineralized enamel surface induced by poly(amido amine) dendrimers

The aim of this study was to investigate the surface topography of remineralized enamel induced by poly(amido amine) (PAMAM) dendrimers and evaluate Streptococcus mutans (S. mutans) adhesion on regenerated enamel for the first time. PAMAM-COOH and PAMAM-NH₂ were used as organic templates to induce enamel surface remineralization. The mineral deposits after remineralization were characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The surface topography of the remineralized enamel was analyzed by atomic force microscopy (AFM). An AFM tipless cantilever was functionalized with S. mutans and acted as a force probe to measure the adhesion force between bacteria and the remineralized enamel surface. Colony-forming unit (CFU) counts of biofilm on remineralized enamel surface were performed after 24 h incubation in S. mutans suspension. Both PAMAM-COOH and PAMAM-NH₂ achieved effective remineralization on demineralized enamel surfaces, which smoothed the enamel surface and reduced S. mutans adhesion. PAMAM dendrimers are promising materials for early caries treatment because of their excellent remineralization ability. The remineralization induced by PAMAM dendrimers smoothed the surface and reduced S. mutans adhesion, which could prevent secondary caries.