Symptoms such as deep decay, large fillings, trauma to the tooth, a chipped tooth or even repeated dental work can all contribute to the need for root canal treatment.  You may need a root canal if a tooth is causing you pain or if the gums adjacent to the tooth are tender and swollen. Another symptom is if the tooth appears discoloured and has become extra sensitive to heat and cold.

Dental cavities, chipped teeth, cracked dental fillings, and injury to the teeth can cause damage to the dental pulp. Cracked dental fillings allow saliva and harmful bacteria to reach the root canal and infect the pulp. Fractured teeth can expose the pulp. Injury to the teeth can cause pulp damage even if there are no external signs of damage to the inside of the teeth. If inflamed and infected pulp inside the tooth is revealed then your family dentist may recommend a root canal procedure.

When the nerves inside the tooth pulp die, the dentin and enamel can no longer absorb nutrients and moisture. The inflamed tissue in the gum line causes toothache, and infection can damage the bones around the teeth. If the damaged pulp is left untreated, bacterial infection and inflammation can loosen the tooth and it may have to be removed. Therefore, root canal therapy is necessary to preserve the tooth and also protect the jawbone.

Process

• First, the dentist studies the x-ray of the infected tooth and then administers a local anesthetic.
• Then, the dentist removes the inflamed nerve tissue through an opening in the crown of the tooth. The root canal is cleaned properly so that no debris or bacteria is left behind. This will ensure that infection and tissue swelling does not happen again.
• The dentist will then seal off the cleaned root canal cavity. This is to prevent fluids and bacteria from entering the cavity.
• Next, the root canal is filled with a natural rubber material (gutta-percha) and an adhesive cement mixture. 
• Finally, a crown is placed on the sealed tooth which allows the tooth to function normally.