People with exposed dentine are susceptible to tooth sensitivity, triggered, for example, by cold drinks or hot food. Sensodyne formulas work in two different ways: Sensodyne toothpastes with potassium nitrate works to soothe the nerves inside the tooth. Sensodyne Repair & Protect with Novamin builds a robust reparative layer over the exposed dentine to create a barrier to pain triggers. Each Sensodyne toothpaste, is proven to relieve the pain of tooth sensitivity with twice daily brushing.