Inhibition of dentine caries using fluoride solution with silver nanoparticles: An in vitro study

To investigate the remineralising and staining effects of sodium fluoride (NaF) with silver nanoparticles (AgNPs) on artificial dentine caries.

Human dentine blocks with artificial caries were divided into four groups. Group 1 received 5 % NaF (22,600 ppm fluoride) with 4000 ppm AgNPs; group 2 received 4000 ppm AgNPs; group 3 received 5 % NaF, group 4 received deionised water (negative control). All groups underwent three biochemical cycles. Each cycle included Streptococcus mutans biofilm challenge and remineralisation process. The lesion depth, mineral-organic content, surface morphology and crystal characteristics of dentine blocks were evaluated using micro-computed tomography, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction. Colour change of dentine blocks was assessed using spectrophotometry.

The mean lesion depths of groups 1-4 were 151.13 ± 29.13 μm, 172.38 ± 23.44 μm, 190.41 ± 32.81 μm and 221.24 ± 27.91 μm, respectively. The hydrogen phosphate-to-amide I ratios of groups 1-4 were 5.98 ± 0.36, 3.86 ± 0.56, 4.00 ± 0.67 and 2.53 ± 0.40, respectively. There was no significant interaction effect between AgNPs and NaF. SEM showed less exposure of dentine collagen fibres in group 1 when compared to other groups. X-ray diffraction revealed presence of silver chloride and metallic silver in group 1 and 2. There was no significant difference in colour change among the four groups (p = 0.74).

NaF solution with AgNPs can remineralise dentine caries without staining.

Sodium fluoride solutions that include silver nanoparticles have potential uses in the management of caries.