This study will investigate the longitudinal efficacy of two experimental oral rinses, one containing 1.5% weight/weight (w/w) dipotassium oxalate monohydride (KOX) /0 Parts per Million (ppm fluoride) and the other 2.0% w/w KOX /45ppm fluoride, for the relief of dentinal hypersensitivity (DH), compared to a placebo oral rinse, when used as an adjunct to twice daily brushing with a standard fluoride toothpaste.