The effect of nano-silver fluoride in remineralization on artificial dentine caries: an in vitro study

Abstract

The aim of this in vitro study was to compare the remineralization efficiency among Nano-silver fluoride 400 ppm (NSF400), 38% Silver diamine fluoride (38% SDF) and 5% Sodium fluoride (5% NaF) on artificial dentine caries in permanent molar or premolar teeth. The teeth were sectioned to obtain 120 specimens (3 x 3 x 2 mm3). After artificial caries were created, the lesion depth (LD) was measured using Micro-computed tomography (Micro-CT) (n=15 specimens/group), and the surface microhardness (SMH) was measured using a Knoop microhardness tester (n=15 specimens/group). Subsequently, all specimens were randomly assigned to four groups: Group 1) NSF400, Group 2) 38% SDF, Group 3) 5% NaF, and Group 4) Deionized water (control group). Experimental treatments were applied. All specimens were immersed in culture media containing Streptococcus mutans and Candida albicans for 24 hours to create a biofilm and underwent a biofilm pH-cycling for 7 days. The measurements of lesion depth and surface microhardness were conducted after the treatment. The results before and after treatment were compared using the paired t-test. Then, the mean percentage change in lesion depth (%LD change) and the mean percentage of surface microhardness recovery (%SHR) among the groups were compared using One-way ANOVA with Tukey's post hoc test (p<0.05). The results showed that after treatment, Groups 1 and 2 had a significant decrease in mean LD, while Groups 1, 2, and 3 exhibited a significant increase in mean SMH compared to their pre-treatment values. The %LD change in Groups 1, 2, 3, and 4 were -7.80 ± 3.70, -12.69 ± 4.66, 1.66 ± 4.80, and 8.34 ± 3.62, respectively. Group 1 exhibited a significant decrease in %LD change compared to groups 3 and 4 (p<0.001), but it was significantly lower than group 2 (p=0.013). The %SHR of groups 1, 2, 3, and 4 were 7.86 ± 3.15, 10.49 ± 1.82, 1.60 ± 1.52, and -1.44 ± 0.79 respectively. Group 1 exhibited a significantly higher %SHR compared to groups 3 and 4 but it was lower than group 2 (p<0.001). In conclusion, the Nano-silver fluoride 5provided remineralization effects on artificial dentine caries better than 5% Sodium fluoride varnish but not as effectively as 38% Silver diamine fluoride.