Antibacterial and mineralising properties of silver complex fluoride on enamel caries: An in vitro study.

OBJECTIVE

This study aimed to investigate the antibacterial and mineralising effects of silver complex fluoride (SCF) on enamel.

METHODS

Sound human enamel blocks were prepared and subjected to Streptococcus mutans-induced demineralisation to create artificial caries. Blocks were treated with SCF, 38% silver diamine fluoride (SDF), or deionised water and underwent a 21-day pH-cycling. Biofilm morphology, viability, and quantification were analysed using scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and colony-forming unit (CFU) counting. Remineralisation effects were assessed by SEM, micro-computed tomography (micro-CT), Knoop microhardness, and X-ray diffraction (XRD).

RESULTS

SEM images showed dense bacterial biofilm on water-treated enamel, but minimal growth on SCF- or SDF-treated surfaces. CLSM indicated higher dead/live cell ratios in SCF (0.75 ± 0.22) and SDF (0.83 ± 0.25) groups than water (0.43 ± 0.22; p < 0.001). Log CFU values for SCF, SDF, and water were 6.90 ± 0.09, 6.74 ± 0.23, and 7.78 ± 0.13, respectively (p < 0.001, SCF, SDF < Water). Lesion depths (μm) were 91 ± 36, 89 ± 24, and 186 ± 34 (p < 0.001; SCF, SDF < Water), while mineral loss (gHA pcm⁻³) was 0.43 ± 0.13, 0.40 ± 0.14, and 1.32 ± 0.21 (p < 0.001; SCF, SDF < Water) for SCF, SDF, and water, respectively. Knoop hardness was significantly higher in SCF (70 ± 2) and SDF (72 ± 7) than water (25 ± 6; p < 0.05). XRD confirmed well-crystallised hydroxyapatite in SCF- and SDF-treated enamel but not in water-treated samples.

CONCLUSION

SCF demonstrates antibacterial and mineralising properties comparable to SDF.

CLINICAL SIGNIFICANCE: Adoption of SCF may expand silver-based caries prevention by improving patient acceptance without compromising appearance.