Parkinson, CharlesBurnett, Gary R.Creeth, JonLynch, RichardBudhawant, ChandrashekharLippert, FrankHara, Anderson T.Zero, Domenick T.2018-04-202018-04-202018Parkinson, C., Burnett, G. R., Creeth, J., Lynch, R., Budhawant, C., Lippert, F., … Zero, D. T. (2018). Effect of phytate and zinc ions on fluoride toothpaste efficacy using an in situ caries model. Journal of Dentistry. https://doi.org/10.1016/j.jdent.2018.03.013https://hdl.handle.net/1805/15885Objectives To compare and explore the dose-response of phytate-containing 1150 ppm fluoride toothpastes on model caries lesions and to determine the impact of zinc ions. Methods This was a single-centre, randomised, blinded (examiner/laboratory analyst), six-treatment, four-period crossover, in situ study in adults with a removable bilateral maxillary partial denture. Study treatments were toothpastes containing: 0.425% phytate/F; 0.85% phytate/F; 0.85% phytate/Zn/F; F-only; Zn/F and a 0% F placebo. Where present, F was 1150 ppm as NaF; Zn was 0.3% as ZnCl2. Human enamel specimens containing early-stage, surface-softened (A-lesions) or more advanced, subsurface (B-lesions) caries lesions were placed into the buccal flanges of participants’ modified partial denture (one of each lesion type per side). A-lesions were removed after 14 days of twice-daily treatment use; B-lesions were removed after a further 14 days. A-lesions were analysed for surface microhardness recovery. Both lesion types were analysed by transverse microradiography and for enamel fluoride uptake, with B-lesions additionally analysed by quantitative light-induced fluorescence. Comparison was carried out using an analysis of covariance model. Results Statistically significant differences between 1150 ppm F and the placebo toothpastes (p < 0.05) were shown for all measures, validating the model. No differences between fluoride toothpastes were observed for any measure with little evidence of a dose-response for phytate. Study treatments were generally well-tolerated. Conclusions Results suggest phytate has little impact on fluoride’s ability to promote early-stage lesion remineralisation or prevent more advanced lesion demineralisation in this in situ caries model. Similarly, results suggest zinc ions do not impair fluoride efficacy.enAttribution-NonCommercial-NoDerivs 3.0 United StatescariesfluorideenamelArticle