Tooth decay, fractures or other reasons can cause the vital tissue inside a tooth to become inflamed and painful, and/or diseased resulting in infection, or an “abscessed tooth.” Trauma can also result in a nerve which has died and caused an infection but with no pain at all. This can be found through routine radiographs.
Treatment is either to remove the tooth entirely, or to try and save the tooth through endodontic, or root canal treatment. After appropriate anesthesia the decay is removed and an opening is made through the crown of the tooth into the pulp chamber. With small instrumentation the canals inside the tooth roots are completely cleaned out and shaped.
The canals are then hermetically sealed down to the root tips with a warm condensable rubber cement called gutta percha. Depending on the amount of tooth structure damaged or missing a post and core filling may be necessary, followed by a crown restoration. Sometimes anterior teeth can be restored with a simple filling.
Although root canal therapy is highly successful, it is not 100%. Despite our best efforts sometimes the infection does not resolve. An additional procedure to attempt to save the tooth is an apicoectomy where the root tip is accessed through a surgical incision. Any diseased and inflamed tissue is removed and the tip of the root can also be removed. A small filling may be placed in the remaining tip of the tooth to seal the root canal. The gum is sutured back into place. As healing occurs, new bone fills the defect.
Another possibility is a tooth may have a fracture which makes only part of the tooth unusable. A hemisection procedure can be performed where only the bad part of the tooth is removed. After endodontic treatment the remaining tooth structure can be used for restoration. This must be evaluated in terms of practicality though whether the efforts and investment are warranted or would be better directed towards replacing the entire tooth with a dental implant.