Root Canal Treatment


Two teeth that have been treated with root canal treatments. Note the screw-like structure on the left: this is a dental implant.

Two teeth that have been treated with root canal treatments. Note the screw-like structure on the left: this is a dental implant.

Inside every normal, healthy tooth is a space, containing a nerve, artery, and vein, called the pulp. Inside the part of the tooth that can be seen above the gums (clinical crown) is the pulp chamber. Inside the part of the tooth below the gums (tooth roots) are the root canals (see Parts of the Tooth). When damage to the nerve, artery or vein occurs, the tooth begins to die. If the tooth becomes sensitive or painful, a root canal treatment is recommended to save the tooth.

What is a root canal treatment?

The death of a tooth can occur for a number of reasons, resulting in the need for root canal treatment. Conditions such as:

  • deep decay close to the ‘nerve chamber’ or pulp whereby bacteria involved in the decay process are now entering the pulp chamber and setting up infection.
  • fracture
  • tooth grinding (bruxism)
  • too rapid tooth movement during treatment with braces can result in the death of the tooth and require treatment of the root canal.
  • accidental trauma

When a patient receives a root canal treatment, the tooth is numbed (anesthetized) and an opening is made to allow access to the pulp chamber and root canals. The contents inside the tooth are removed, the walls on the inside of your tooth are smoothed and disinfected. The inside of your tooth is then filled and sealed to prevent bacteria from entering in the filled canals.

A root canal treatment involves removing damaged tissue inside your tooth and filling the space with a material that is very compatible with your body.

Symptoms leading to root canal treatment

The symptoms indicating the need for root canal treatment vary. Typically, when a patient reports a toothache, there are five questions that can help determine whether or not the tooth requires root canal treatment. This list of questions is a guideline in helping to determine if a root canal treatment is needed.

  1. Is any tooth sensitive to heat or cold?
  2. If yes, does the sensitivity linger for 3-5 minutes or does it subside quickly?
  3. Is the tooth pressure sensitive (does it hurt to chew or bite)?
  4. Does the tooth hurt without being disturbed? Does it hurt spontaneously?
  5. Does it wake you when sleeping?

Sometimes only sensitivity to cold occurs, but lingers for five minutes or more. Sometimes only pressure sensitivity occurs, but pain without touching the tooth, that wakes the patient up at night, and extreme heat sensitivity are strong indications that the tooth is dying.

Cold sensitivity and pressure sensitivity could mean something other than pulpal death, such as a filling that is too high or a microscopic crack in your tooth. Pain that wakes someone from a sound sleep could be from an intense episode of Clenching and Grinding. Teeth clenching and grinding (bruxism) is a potentially damaging habit that can cause intense pain that wakes the patient from a sound sleep.

Sometimes patients have no symptoms, but a dark spot around the tip of the root is found on an x-ray, indicating that the tooth has died.

A pulp tester may help the dentist in the diagnosis of the pulp health; however, this device only indicates if there is live tissue inside the tooth. Since the pulp tissue doesn’t die all at the same time, a pulp tester may not be as reliable as an x-ray to answer the questions above.

What creates the need for a root canal treatment?

All living tissues, including teeth, require a blood supply for healing from the damage of trauma. For example, when we get a cavity and the pulp gets irritated, our body has the ability to build up protection from the inside of the tooth, protecting the tooth from the cavity, but too often cavities grow faster than the blood supply can build up protection.

When we cut a finger, there is an enormous blood supply to the wound, allowing it to set up an inflammatory response and begin healing. The problem with teeth is that the blood supply is very small and when the tooth is “injured” badly enough, the resources needed to promote healing cannot get to the injury quickly enough and the tooth can die. A more detailed explanation of causes leading to root canal treatments follows:

  1. Deep tooth decay – Left untreated, Tooth Decay can become severe enough to irritate the pulp, or infect the inside the tooth. Both situations usually lead to death of the tooth. The bacteria involved in this infection grow and reproduce without oxygen. These bacteria produce gases that expand when heated, press on the infected nerve and create intense pain. Bacterial infection usually requires treatment with antibiotics.
  2. Trauma – There are two forms of trauma that may cause your tooth to die: acute trauma (like getting hit in the face with a baseball) or chronic trauma such as tooth grinding. Chronic tooth grinding presses the tooth into the bony socket, compressing blood vessels and choking off the blood supply. Over long periods of time, this habit may cause pulpal death.
  3. Dental treatment – Poor tooth care leading to repeated dental treatment may cause the death of the tooth. Many times, a tooth that has been repeatedly filled and eventually needs a crown, dies after the crown is prepared. Often the patient wants to know what the dentist “did to my tooth”. In reality, the tooth has been repeatedly traumatized (it is harmful for a tooth to be filled over and over) and the crown preparation, which may have been recommended years earlier, causes symptoms to become apparent.
  4. Tooth movement – If a tooth is moved too rapidly, such as with braces (orthodontic treatment), pulpal death can occur. A more important factor in pulpal death during tooth movement is the condition of the tooth prior to treatment with braces. Teeth that have sustained years of trauma from being repeatedly filled or teeth that have suffered years of clenching and grinding can die, even if they are moved slowly. Teeth can only handle a certain amount of stress or trauma before they die.

What are the risks of root canal treatment?

  1. Failure – Sometimes a root canal treatment will simply fail. This means, for some reason, the treatment performed could not completely remove the infection. When this happens, the tooth can be re-treated, usually by a specialist (see Endodontist).
    • Retreatment – This may be attempted if the initial treatment fails.
    • Root Tip Treatment (Apicoectomy) – If the initial treatment fails and the retreatment fails, minor surgery designed to expose the root tip, remove a small portion of it and place a filling into the end of the root may save the tooth from removal (extraction).
    • Extraction – If all treatment fails, removal of the tooth may be necessary.
  2. Perforation – During the opening or filing of the tooth, an instrument can accidentally perforate the tooth from the inside out. This may cause the loss of the tooth if not treated properly.
  3. Broken instruments – If an instrument accidentally breaks inside the tooth, the longevity of the tooth depends on the dentist¬タルs ability to file and fill the tooth beyond the broken tool to the tip of the root.
  4. Tooth Fracture- Once a tooth has died and a root canal treatment has been performed, the tooth is often more brittle. For this reason, a crown is usually recommended to help prevent fracture of the tooth.