Root Canal Surgery: Overview

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In root canal treatment, the infected pulp chamber is removed from inside the tooth that travels down the length of the root to the tip or "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.

Dentist examining boys teeth
Robert Daly / Getty Images

Purpose of Root Canal Surgery

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:

  • Deep decay
  • Repeated dental procedures on the tooth
  • Faulty crown
  • Crack or chip in the tooth

What to Expect on the Day of Surgery

Root canal therapy can be performed 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 non-latex 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 into 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") into 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.


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 may 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.

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  5. .American Association of Endodontists. Root Canal Explained.

  6. American Association of Endodontists. Endodontic Retreatment Explained.

  7. Vishwanath V, Rao HM. Gutta-percha in endodontics - A comprehensive review of material science. Journal of Conservative Dentistry. 2019;22(3):216. doi: 10.4103/JCD.JCD_420_18

  8. Yavorek A, Bhagavatula P, Patel K, Szabo A, Ibrahim M. The incidence of root canal therapy after full-coverage restorations: a 10-year retrospective study. Journal of Endodontics. 2020;46(5):605-610. doi: 10.1016/j.joen.2020.01.025.

  9. National Institute of Dental and Cranofacial Research. Opioids & Dental Pain.

By Shawn Watson
Shawn Watson is an orthodontic dental assistant and writer with over 10 years of experience working in the field of dentistry.