Root Canal Therapy

When a tooth is damaged, the pulp (i.e., the nerve) reacts to the injury by becoming inflamed. As the pulp of the tooth is confined by the dentine anything more than mild irritation, leads to the death of the pulp. Irritation can be from many sources. Heavy biting forces over time as with bruxism can lead to the death of the tooth.

Also exposed dentinal tubules from tooth brush abrasion can in time lead to the death of the pulp. Caries (tooth decay) is the most common cause of dead teeth, when bacteria and their toxins invade the pulp, but also cracks in teeth can lead to irreversible pulpitis as well.

Careful examination and tests confirm the diagnosis of irreversible pulpitis when the pulp in the tooth is dying or is already dead. At this point there are only two treatment options available. They are extraction of the tooth or endodontic therapy. Careful assessment will determine if the tooth can be endodonticly treated as cracks, root fractures and very extensive caries make the tooth unrestorable. All posterior (back) teeth that are endodonticly treated should be protected with a crown.

Often the first step is to replace the filling in the tooth, removing the decay and placing a restoration that seals the tooth stopping re-infection by bacteria. A pre-treatment x-ray is often taken at this time. The pulp chamber is accessed from the top of the tooth so that instruments can be used to clean and shape the canal system in addition to frequent irrigation. It can sometimes be very difficult to find and negotiate all the canals in a tooth, in recent years there have been many advances in endodontics. We now have nickel titanium files and new filling materials.

At the first treatment appointment the canals are shaped and cleaned and disinfected and an x-ray taken to establish the correct length. The tooth is then dressed with a cortico-steriod antibiotic paste and sealed to prevent reinfection. After four weeks, the procedure is repeated, and if the canals are clean and the tooth has been symptomless, then the root filling is placed, checking with an x-ray that the filling goes to the end of the root. If the tooth should still be infected, it is cleaned and dressed and left for a longer period. Redressing the tooth will continue until all has settled and the tooth will eventually be filled. At the end of treatment a final x-ray is taken to ensure that the root canals have been completely filled.