Teeth Sensitivity or dentin hypersensitivity is a medical condition which causes temporary pain in the teeth when you eat or drink hot, cold, sour or sweet foods or while brushing and flossing your teeth. This is caused when the enamel of the tooth wears off exposing the dentin (tissue that is present below the tooth enamel) causing nerve irritation. Brushing too vigorously with a hard bristled toothbrush, teeth grinding, receding gums or gum disease and decay of the tooth surface are some of the reasons that cause exposure of dentine. Treatment options include using a desensitizing toothpaste or application of fluorides to reduce sensitivity. Root canal treatments or dental sealants may be used depending on the cause of your sensitivity. Limiting acidic foods and drinks may also help in reduce the erosion of tooth enamel.