Dual-antimicrobial and remineralizing polymer fluoride for dental care

The objective of this laboratory study is to develop an antimicrobial and mineralizing polymer fluoride.

Poly (diallyldimethyl) ammonium fluoride (PDDAF) was synthesized by substitution reaction between poly (diallyldimethyl) ammonium chloride and silver fluoride. Its chemical structure was evaluated using fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (EDS) and 19 F nuclear magnetic resonance (NMR). The cytotoxicity of PDDAF was evaluated by Cell Counting Kit-8 assay. The minimal inhibitory concentration (MIC) and minimal bactericidal/ fungicidal concentration (MBC/ MFC) of PDDAF against S. mutans, P. gingivalis, E. faecalis and C. albicans were assessed, and microbial morphology was observed under transmission electron microscopy (TEM). Inhibition of S. mutans biofilm formation was tested by scanning electron microscopy (SEM) and confocal laser scanning microscope (CLSM) The surface morphology and elemental composition of demineralized dentin treated with 30% PDDAF (30,000 ppm fluoride) were analyzed using SEM and EDS. The chemical structure and crystal characteristics were analyzed using FTIR and X-ray diffraction (XRD). Samples treated with water or 5% sodium fluoride solution (NaF, 22,600 ppm fluoride) served as controls.

EDS, FTIR and 19 F NMR confirmed the successful synthesis of PDDAF. PDDAF demonstrated IC50 values of 45 ± 5 ppm (human gingival fibroblasts), 133 ± 7 ppm (human dental pulp cells), and 1224 ± 429 ppm (deciduous teeth stem cells), with MICs of 41, 13, 117, and 15 ppm against S. mutans, P. gingivalis, E. faecalis, and C. albicans, respectively. TEM revealed bacterial membrane disruption at MBC/ MFC levels. SEM and CLSM showed anti-biofilm ability of PDDAF. Under SEM, PDDAF promoted dentin remineralization and occluded dentinal tubules. PDDAF-treated group exhibited greater calcium content (42.0 ± 0.7 vs. 34.2 ± 1.7; p < 0.001) and higher Ca/P ratio (1.72 ± 0.04 vs. 1.64 ± 0.04; p < 0.001) than water group. FTIR and XRD showed PDDAF-treated group had more hydroxyapatite formation and less collagen exposure than NaF-treated and water-treated groups.

PDDAF exhibits antimicrobial and remineralizing properties.

PDDAF's dual antimicrobial-remineralizing action offers a novel strategy to combat oral pathogens and remineralize dentin, advancing preventive and minimally invasive restorative dental care.