Teeth may become sensitive for a variety of reasons. Tooth sensitivity occurs most often due to dentin exposure, although it may also occur when the pulp of the tooth is irritated or injured.

Causes of tooth sensitivity include:

• Gum recession. When the gums recede, the tooth root becomes exposed, causing increased sensitivity of the tooth. This is the one of the most common causes of tooth sensitivity. Gum recession usually affects more than one tooth and may be caused by a number of factors, including periodontal (gum) disease and surgery on the gums.
  
  
• Tooth abrasion. When the enamel and cementum of teeth are worn away, dentin may become exposed and tooth sensitivity usually results. This is a common cause of tooth sensitivity, usually due to aggressive brushing of the teeth. Some teeth whitening products, including toothpastes, use abrasive ingredients that contribute to the wearing of enamel. Sodium pyrophosphate, used in tartar-control toothpastes, can also make teeth more sensitive.
  
  
• Tooth decay or damage to restorations. Cavities and cracks in fillings or crowns are examples of factors that can cause tooth sensitivity.
  

  

• Cracks or fractures in teeth. When cracks or fractures in tooth enamel occur, it may cause tooth sensitivity and pain, usually when biting or chewing.
  
  
• Recent dental work. Patients may experience lingering discomfort and tooth sensitivity from recent dental work, such as fillings or crowns.
  
  
• Bruxism. Pressure on the teeth from excessive clenching or grinding can cause teeth sensitivity.
  
  
• Frequent vomiting. Frequent, persistent vomiting (e.g., cyclic vomiting syndrome) may also cause sensitive teeth as the digestive acids wear away tooth enamel.