Has your veterinarian advised you that your pet has a fractured or dead (non-vital) tooth? In many cases these teeth can be saved with root canal therapy and extraction may be avoided. Root canal therapy is a type of endodontic procedure that is performed on teeth that are no longer vital (alive). This may occur due to fracture or other types of trauma that result in disease to the delicate dental pulp tissues contained within the tooth.
The Dental Pulp
The dental pulp is the name given to the nerves, blood vessels and soft tissues in the canal or chamber inside the tooth. Some people commonly refer to the pulp as the “nerve” of the tooth although nerves are just one part of the make-up of the dental pulp. This pulp enters at the end of the tooth root and runs up the centre of the tooth to the crown. The chamber containing the pulp is often just called the root canal.
The main function of the dental pulp is to keep the tooth alive and healthy. The nerves supply sensation to the tooth (and when irritated signal dental pain!). The blood supply and tissues allow continued production of dentine inside the tooth to strengthen the tooth internally as the enamel wears with age. This means that the root canal gets narrower with age (in the young animal it is a large, wide space whilst in the old animal it is almost obliterated).
The tooth itself does not stay in the mouth whether it is vital or not. It stays as long as the supporting structures are healthy. The support structures for teeth are the gums, periodontal ligament and surrounding bone. Hence good, healthy teeth can be lost due to severe gum disease (periodontal disease) and non-vital teeth can remain if the support structures are healthy. Therefore, root canal therapy can allow non-vital teeth to remain and function as normal.
How does the pulp become diseased?
In animals, the most frequent cause of pulp death is a result of tooth fracture. Bacteria gain access to the root canal and the pulp becomes inflamed and infected. The result of this is a tooth root abscess after the bacteria spread down through the root canal and into the surrounding bone.
Pulp death can also occur as a result of excessive wear of the teeth (such as dogs with flea allergy dermatitis), trauma to the teeth (which causes internal bleeding in the pulp chamber and a build-up of pressures and inflammation) and sometimes for no apparent reason at all (which means that the tooth will look OK externally).
What is involved with root canal treatment?
During root canal treatment, an access is made into the tooth (this may be through the fractured area) to allow instruments to be used to remove all of the diseased material. During this process, the canals are cleaned, shaped and dried. Next, the root canal is filled with material that forms a seal to prevent infection re-establishing in the root canal system. The final stage involves a restoration (filling) to seal the access and pulp exposure.
In some cases it may be recommended that the tooth also has a crown fitted to protect the remaining tooth structure although this is usually not required.
How successful is root canal therapy?
We won’t attempt root canal therapy if we don’t think it has good chance of success. Of course, no guarantees can be given as pets will be pets and they can damage teeth again following treatment. We also see a small percentage of teeth fail to respond to standard treatment and evidence of disease remains when assessed with dental radiographs.
Whilst most teeth treated with root canal therapy will last your pets lifetime (>90%), we need to ensure all is progressing well (our pets are very bad at telling us when something is wrong), periodic follow-up x-rays are essential to assess that there is no deterioration around the tooth root and all remains well.