Evaluation of the remineralisation of enamel by different formulations and concentrations of fluoride toothpastes in vitro

Aims: \n \nTo investigate the remineralising potential of toothpastes with different formulations of fluoride (F): amine fluoride (AmF), sodium monofluorophosphate (MFP), sodium fluoride (NaF) and stannous fluoride (SnF) on artificial subsurface caries lesions in vitro. A secondary aim was to investigate the remineralising potential of toothpastes containing sodium fluoride (NaF) formulation at different F concentrations (500, 1000, 1450, 2800 and 5000 ppm F) on artificial subsurface caries lesions in vitro. \n \nMaterials and methods: \n \nBovine enamel slabs were subjected to a pH cycling model after 2 weeks of immersion in a demineralisation buffer, to produce subsurface enamel lesions. The pH cycling regime ran for 28 days. Enamel subsurface lesion images were taken using a Quantitative Light-Induced Fluorescence (QLF) system under controlled conditions at baseline and endpoint of the experiment. All fluorescence images were examined with analysing software (QA2 version 1.16; Inspektor Research Systems). \n \nResults: \n \nFor the different F compounds, significant (p < 0.05) remineralising potential was observed for the NaF, SnF and MFP groups in descending order. Lesion remineralisation for the AmF and F-free groups was not significant. As for the different fluoride concentrations, all fluoride concentrations showed significant (p < 0.05) remineralisation potential when compared to the 0 ppm F control group, but no significance was found between groups. \n \nConclusions: \n \nFrom the results of phase A of this in vitro study, it was concluded that: A statistically significant remineralisation of enamel subsurface lesions in comparison with the baseline was found in all groups except the AmF group. Furthermore, NaF toothpaste had the highest remineralising potential on artificial subsurface carious lesions in vitro, followed by SnF then MFP, while AmF was less than the F-free toothpaste. \nThe results of phase B of this in vitro study, concluded that: A statistically significant remineralisation of enamel subsurface lesions in comparison with the baseline was found in all groups. However, there was no difference in the effect of toothpastes with sodium fluoride (NaF) formulation and different concentrations (500, 1000, 1450, 2800, and 5000 ppm F) on remineralisation of artificial subsurface carious lesions in vitro, and no apparent dose response was present related to the concentration of fluoride. \n