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

Abstract

Objectives: To investigate the remineralising and staining effects of sodium fluoride (NaF) with silver nano-particles (AgNPs) on artificial dentine caries. Methods: 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. Results: 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). Conclusions: NaF solution with AgNPs can remineralise dentine caries without staining. Clinical Significance: Sodium fluoride solutions that include silver nanoparticles have potential uses in the management of caries.