SENSODYNE RAPID ACTION WITH FLOURIDE 75ML TP,contains strontium which acts to create a mineral-like seal over the surface of the dentine and within the microscopic channels. This prevents stimulus from reaching the nerve. Brush twice daily and not more than three times, minimise swallowing and spit out, it provides long lasting protection from sensitivity. Also the fluoride helps to protect and strengthen teeth, for rapid relief, first squeeze a pea sized amount of product on to a clean finger tip gently rub on to the base of the sensitive tooth for 1 minute a maximum of two times per day.