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What is a Root Canal?

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Updated April 08, 2014

Question: What is a Root Canal?
The space inside the tooth from the center, known as the pulp chamber, that travels down the length of the root to the tip (or apex) is called a "canal," or more specifically, a root canal. Human teeth may have one to four root canals, depending on the anatomy of the tooth. Molars, may have 2 to 4 canals, premolars may have 1 to 2 canals, cuspids may have 1 to 2 canals, and finally incisors generally have 1 canal. Extra canals may branch out from the main canal, called "accessory canals." The number of canals and the anatomy can vary among teeth.
Answer:

Common Reasons for Root Canals

The tiny canals contain the pulp of the tooth also commonly referred to as the nerve, which originates from the pulp chamber. Any trauma or infection of the nerve will result in the need for root canal therapy. Common reasons for root canal therapy include:

  • Tooth decay invades the tooth, penetrating through the enamel and then the dentin in to the pulp.

  • A tooth has become abscessed -- also known as infected -- from decay.

  • Trauma, such as a chipped or broken tooth, occurs and results in the exposure of the nerve.

  • A tooth is slowly dying, due to aging or past trauma that did not result in the need for treatment at the time of injury.

How Is Root Canal Therapy Performed?

Root canal therapy can be preformed in single or multiple visits. Before the procedure, though, your dentist will advise you as to the number of appointments necessary to complete the canal. If you had an infection or abscess in the tooth, the dentist may choose to have you start antibiotics before completing the root canal. Your dentist will begin the appointment by giving you local anesthetic to "numb" the tooth that is being worked on.

After your tooth is "numb", you may expect the following procedures:

  • A dental x-ray of the tooth, displaying the entire tooth in the film (called a "periapical x-ray"), is taken for the dentist to refer to during the procedure.

  • The dentist will place a rubber dam over your mouth. This plastic shield, made from either latex or nonlatex materials, is used to keep the tooth isolated from your saliva and very dry before the final steps are taken to complete the procedure. The dentist will use different chemical solutions to disinfect the inside of the tooth. The rubber dam is helpful in keeping these solutions from entering your mouth.

  • Next, the dentist will begin the procedure by drilling a small hole through the tooth in to the area known as the pulp chamber -- this is where the nerve of the tooth is located.

  • Your dentist will begin using tiny files, which are designed to remove the nerve from the tooth and any infected tissue. Certain files can be used by hand; others are connected to a slower moving dental hand piece, called a "rotary instrument." The dentist may require another x-ray at this point to determine the length of the root. It is critical that the entire nerve is removed to prevent toothaches after the procedure and re-infection of the tooth, which would result in the need for retreatment or extraction of the tooth. In order to prevent this, the dentist needs to get as close to the tip, or apex of the tooth, to remove all of the nerve. This is usually the longest part of the procedure.

  • Once the dentist is confident that the entire tooth has been cleaned out, the tooth is dried with tiny absorbent paper points. When completely dry, the dentist will place a material (called "gutta percha") in to the tooth. Gutta percha is a rubber material designed to seal the inside of the tooth.

  • Your dentist will remove any remaining decay from the tooth and will decide to either put a temporary filling on to close the tooth or proceed with placing a permanent filling. If your root canal is performed by an endodontist; a dentist that specializes in root canals, he will place a temporary restoration and send you back to your general dentist for the restoration. Chances are, your dentist will recommend having a crown put on to the tooth. Since the nerve and blood supply to the tooth has been taken away, the tooth may become brittle over time, resulting in a cracked tooth. A crown is designed to prevent this from happening.

Recovering from Your Root Canal Therapy

When the local anesthetic has worn off, your tooth may be sore from the procedure. Your dentist may recommend a pain reliever to take at home, and depending on the circumstances behind your root canal, antibiotics my be prescribed to clear up any remaining infection in the tooth. If you were on antibiotics before the procedure, your dentist will instruct you to finish the remaining medication.

Sources:

The American Association of Endodontists. "What is Endodontic Treatment?"

The American Dental Association. "Root Canal (Endodontic) Treatment.

The Canadian Academy of Endodontics. "Patient Learning Centre- Endodontic Treatment."

The Canadian Dental Association: Your Oral Health. "Root Canal Treatment."

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