Sharp Pains

• Teeth bleaching treatments that involve the use of a custom-fitted mouth guard have been reported to cause sudden, intense pain. Dentists call these pains "zingers." Stop using the bleaching product immediately and visit your dentist as soon as possible if you experience any pain.
  
  

Gum Damage

• When teeth bleaching products are used over a long period of time, they can cause irritation to the gum. Extended use can result in permanent damage. The risk of gum irritation and damage is higher if the mouthguard is ill-fitting, causing the bleaching agent to leak.
  
  

Enamel Damage

• Some home remedies that are used for teeth bleaching are formulated from fruits such as strawberries and lemon, which are specifically selected for their high acid content. This high acid content may corrode the tooth enamel, causing damage.
  
  

Tongue Cancer

• According to researchers at Georgetown University Hospital, the hydrogen peroxide in some teeth bleaching gels may be responsible for causing tongue cancer in two of their patients. (See Resources). While animal studies seem to support this finding, no human tests have been conducted to verify the link.
  
  

Sensitivity

• Teeth bleaching can cause heightened sensitivity of the teeth. This in turn can cause pain when you eat certain types of foods, such as cold colas, hot coffee or chocolate.