Experimental antibacterial and mineralizing calcium phosphate-based treatment for dentin surfaces

Objectives: This study aimed to determine the efficacy of experimental calcium phosphate-based solutions (sCaP) containing fluoride (F), with and without zinc (Zn) ions on reducing susceptibility to acid dissolution and Streptococcus mutans (S. mutans) colonization of dentin surfaces.Methods: Dentin sections were treated with double distilled water (control) and with sCaP solutions differing in pH and in F- and/or Zn2+ ion concentrations. Solutions A (pH 7); B, C, and D (pH 5.5); solution C, twice Zn2+ and F- ion concentration compared to B; solution D is similar to C but without Zn2+. The dentin surfaces were characterized using scanning electron microscopy (SEM), x-ray diffraction, and Fourier Transform Infrared spectroscopy. Dissolution was determined in acidic buffer. Bacterial (S. mutans) attachment and growth were evaluated using SEM and Bioquant. Statistical analyses applied analysis of variance (ANOVA) and Duncan's multiple Range test.Results: Compared to control, dentin surfaces treated with sCaP solutions showed: (a) occluded dentin tubules; (b)reduced susceptibility to acid dissolution; and (c) Zn2+ ions were more effective than F- ions in inhibiting bacterial colonization.Significance: Acidic sCaP containing both F and Zn ions have mineralizing, acid resistance, and antibacterial effects and may be potentially useful as a strategy against dentin caries formation and progression.