Root canal treatment is generally recommended when there is infection or injury to the tooth’s pulp – the soft tissue (nerve endings, blood vessels and connective tissue) at the center of every tooth.

Specific conditions that may require root canal treatment include the following:

• Deep cavity. Untreated dental caries caused by rampant tooth decay. When plaque builds up on teeth, bacteria can eat into the enamel (the hard outer layer) and continue to the dentin layer below. That dentin surrounds the pulp. When decay reaches the pulp, it can cause irreversible pulpitis, a prolonged inflammation with internal tooth pressure leading to decreased blood flow to the pulp. Eventually, the pulp tissue dies (necrosis) and further infection (an abscess) can form in the gums or tooth roots. An abscess is a painful pocket of pus that may emit tissue-destroying toxins. If left untreated, the abscess can lead to erosion of the connective tissues and bones anchoring teeth to the jaw (periodontium).

  

• Unsuccessful previous root canal treatment. If infected tooth or pulp tissue was not completely removed during an initial root canal procedure, there is a chance of reinfection and renewed pain. According to the Academy of General Dentistry, root canal treatments have a 5 percent failure rate. Other factors that might prompt a second procedure are when a canal is fractured by a dental instrument during the initial treatment or when a branch of a root canal goes unnoticed during the first procedure.
  
  
• Weakened teeth. Repeated fillings, broken crowns or root fractures (caused as a result of or following dental procedures) may cause a tooth to lose so much of its structure that a root canal is necessary to strengthen the tooth. The dentist or endodontist can put a metal or plastic post into the root and recap the crown to help save the tooth.
  
  
• Acute dental trauma. This may include sports injuries, auto accidents or other trauma to the face or mouth. The types of tooth injuries include:
  
  
• • Crown fracture. When the pulp is exposed due to a chipped, cracked or broken tooth crown.
    
    
  • Crown/root fracture. When the enamel and dentin in the crown as well as the cementum covering the root are cracked or damaged. This can occur with or without exposure of the pulp.
    
    
• Sensitive teeth. If other attempts to desensitize teeth (e.g., special toothpastes, resins and gels) fail to work, the dentist may recommend a root canal treatment to remove the tooth’s nerve center. Sensitivity to hot and cold sensations on the tooth or on roots exposed by gum recession can cause pain and discomfort. Pain when consuming hot foods and drinks can indicate the nerve is dying.

Root canal treatment may be necessary if severe pain results from biting, touching or pushing a tooth. Swelling near the tooth may also indicate the need for treatment.