Dentine is a slightly softer material than the enamel that covers it. It contains tiny holes – or tubules – through which acids, sugars and liquids can reach the sensitive nerve of the tooth. Sensitivity in your tooth suggests that dentine, the layer below the enamel surface of the tooth, is exposed somewhere.
Causes of dentine exposure
- Tooth decay
- If a tooth becomes sensitive it may have developed a cavity. This allows food, drink and cold air access to the sensitive layers of the tooth.
- Receded gums
- Gums can recede as a result of gum disease, over-enthusiastic brushing, or the use of a hard toothbrush. The root of the tooth is not protected by enamel. When the gum recedes and reveals more of the tooth, it exposes this sensitive root surface.
- Having plaque on the root surface of your teeth can produce sensitivity. This is due to the toxins and acids that are produced by the plaque bacteria entering the tubules in the exposed dentine and stimulating the nerve endings deeper within the tooth.
- Acidic food, drink or mouthwash
- Acids in some mouthwashes, in foods such as oranges and tomatoes, and in drinks like fruit juices and soft drinks and sports drinks, can gradually erode tooth enamel to expose the dentine.
- Cracks in the teeth
- Cracks in the enamel of the tooth allow food particles and liquids access to the deeper layers of the teeth. These cracks can also fill with bacteria and cause inflammation.
- Wear and tear to the enamel
- Over time, chewing, tooth-grinding (bruxism) and brushing too hard can all wear away enamel, exposing the dentine underneath.
- Tooth-whitening products
- Products that contain baking soda or peroxide to whiten teeth can cause microscopic damage to tooth enamel and give rise to tooth sensitivity.