Root canal treatment is needed for two main reasons. The first is infection. An untreated cavity is a common cause of pulp infection. The decay destroys the enamel & dentin of the tooth until it reaches the pulp. Bacteria then infect the pulp & antibiotics can’t get to infections inside teeth. The inflammation caused by the infection reduces the blood supply to the tooth & can cause severe pain. The reduced blood supply also keeps the pulp from healing.
The second reason for a root canal is damage to the pulp that can’t be fixed. A fracture in a tooth or a blow to the tooth (trauma) can damage the pulp. Multiple filings or other restorations on the same tooth also can damage the pulp.
Root canal treatment eliminates infection, or the potential for infection, by removing damaged pulp from within the tooth & sealing the canal against bacteria. Endodontic procedures require isolation, sterilization & x-rays & may require multiple visits to the dental office.