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Root Canal Therapy


When the inside of a tooth becomes infected, pressure begins to build. Teeth are hard and cannot expand. The increased pressure inside the tooth irritates the tooth's nerve, causing pain. This pain and infection can lead to biting and chewing issues, poor nutrition, and poor oral hygiene. Dental infections left untreated can lead to tooth loss, and if they spread beyond the jaw may cause serious and sometimes life-threatening problems.

Root canal therapy eliminates an infected tooth's pain and swelling by removing the infection and sealing the tooth. The procedure can repair and save your tooth rather than having it removed.

Whether a tooth will need root canal therapy depends on many factors, including the extent of the damage or decay to the original tooth, your age, and your overall health. For example, you may require root canal therapy if your tooth is severely damaged and treating it requires structural posts to be placed into the tooth. Root canal therapy may also be needed when preparing a tooth for a restoration, such as an implant or crown.

Root canal therapy consists of many steps. Your procedure may vary from the process described below based on your specific situation.

Before the procedure

  • Antibiotics: Your dentist may prescribe antibiotics if you have a dental infection that has spread beyond the tooth.
  • Review your health status: You will share information to ensure that your dentist and their staff can provide safe and effective treatment and provide appropriate post-care guidance. Get important information here: Health history and current health status.
  • Treatment review: Your dentist will review the procedure with you, including its risks, benefits, and options you may have. Understanding the process will lead to the best treatment outcome. Ask any questions you have before starting the procedure.
  • Anti-anxiety medication: If you are anxious about dental procedures, your dentist may recommend sedation.
  • X-ray images: Your dentist will take X-ray images and review them to develop a plan to correct the issue. The dentist will then evaluate your tooth's length and study the root canals for obstructions and other features. Some dentists are now using 3D X-ray images known as Cone Beam CT scans to help detect tooth root fractures or root canals difficult to identify in a traditional X-ray.

During the procedure

  • Anesthetic: The tooth is usually numbed by injecting a local anesthetic around the tooth's nerves. Your dentist may also use a topical numbing gel to relieve any discomfort before the injection.
  • Preparing the site: The tooth is isolated from mouth structures like the tongue and cheeks with an isolation barrier known as a rubber dam.
  • Access hole: Your dentist will drill an access hole into the tooth's root canal. If the tooth has a crown, onlay, inlay, or filling, the hole is made through the restoration and repaired or replaced after the root canal is completed.
  • Performing the procedure:
    • Your dentist will remove the nerve tissue and blood vessels from the root canal, then disinfect the tooth's hollow interior with an antibacterial solution.
    • The canal will then be cleaned, enlarged, shaped, rinsed, and dried.
    • Your dentist will then fill the root canal with a resin that seals the tooth against future bacterial infection. This fills the inside of the canal to the tip of the roots and seals any smaller side canals.
    • Your dentist may take multiple X-ray images during the root canal procedure to guide their use of instruments needed to remove infected pulp tissues.

After the procedure

  • Additional services: If your tooth has more than one cusp (for example, a premolar or molar tooth), there is a high probability that your tooth will need a crown following root canal therapy. You should schedule this procedure soon after the root canal.
  • Follow-up care: Your dentist will give you specific instructions on how to take care of the treated area and expected healing times. You should request a copy of the instructions. Although the instructions may seem straightforward at the time of your dental appointment, you may have questions and need to refer to them later.

There are some issues to consider before deciding on root canal therapy. They may not apply to your specific situation.

  • You may experience some temporary numbness, pain, and/or swelling following the procedure.
  • Your dentist cannot guarantee that root canal therapy will prevent future infections. Following a root canal, teeth can become reinfected and require additional treatment to relieve pain and swelling.
  • After your root canal is completed, your tooth has the potential to crack before your dentist places a crown or onlay. Your dentist should advise you of this possibility before beginning treatment. If it is a large crack, your dentist may not be able to save your tooth, resulting in additional treatments. Although much less likely, teeth sometimes crack in the roots even after a crown is placed.
  • If your dentist finds additional problems in your tooth, they may not be able to complete the root canal procedure. They will advise you on other options.
  • Your dentist may not be able to fully clear the root canal of obstructions such as calcified areas, which may reduce the procedure's effectiveness.
  • While unusual, it is possible for pieces of the instruments used to clean and shape root canals to break off inside the tooth. If this happens, the root canal therapy may not be successful.
  • If the tooth cannot be saved by root canal therapy, tooth removal is usually an option. However, it is important to consider the problems that arise from tooth loss if you don't replace the tooth.
  • Your dentist may be able to place a bonded composite resin filling to stabilize the tooth long enough to allow you to budget for the cost of an onlay or crown.
  • Antibiotics and pain relievers can offer temporary relief for symptoms of some infections, but if the infection is not resolved the pain and infection will return.
  • Failure to treat an infected tooth will ultimately lead to tooth loss. This can cause other problems if you do not have the tooth properly treated and replaced.
  • Untreated infections can progress to life-threatening situations, especially if you have a weakened immune system. Some situations can be especially dangerous:
    • If you have significant swelling in the upper part of your face, seek medical or dental attention immediately. Infections in the upper jaw can be very serious. Bacteria can travel through your veins and into the sinus region of the brain.
    • Swelling and infections that constrict your airway are life-threatening. If you have significant swelling that you feel is impairing your ability to breathe and swallow normally, call your local emergency number (911 in the US) immediately.
  • You can delay treatment or decide not to be treated, although these options may not be in your best long-term interest.
  • If I have root canal therapy on my tooth, will it be restored to its proper function and appearance?
  • What are my options to root canal therapy for this tooth? Would tooth removal and replacement with an implant offer a better chance of success? What would the cost of the implant, a replacement crown, and other services I may need?
  • Will my tooth need to have other procedures after root canal therapy? If so, what are they, and how quickly should this treatment be done? What are the costs?
  • What are the risks associated with root canal therapy?
  • What is the possibility that the root canal will not be successful, and I will need retreatment?
  • If I have excessive pain or swelling after my root canal therapy, what should I do?
  • How should I take care of my tooth after root canal therapy?

Author: Symbyos staff, Fluent staff
Last updated: 3/1/2021Medical review: Thomas J. Greany DDS, 12/29/2020
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