To compare the salivary fluoride concentrations of different fluoride formulations in the form of toothpaste, with and without post-brushing water rinsing. Toothpaste formulations are to include: sodium fluoride (NaF), sodium monofluorophosphate (MFP), sodium fluoride plus sodium monofluorophosphate combined (NaF + MFP), Amine fluoride (AmF) and stannous fluoride and sodium fluoride combined (SnF + NaF). Fluoride-free toothpaste will serve as a control in this study. Concentration is to be standardised for all the formulations.