August 6, 2010

Dog & Cat Root Canal Therapy

When is a root canal necessary for your pet?

Your pet’s teeth have a small hollow area inside the entire tooth, called the ” root canal system”. This cavity contains the normal nerves, blood vessels, and other tissues that support and nourish the tooth. When this tissue is exposed by a dental fracture or dies secondary to trauma, the inside of the tooth becomes a reservoir of infection that can never heal. The contents of the canal leak out the tip of the root over time, creating problems around the end of the root. The tooth may eventually fall out, but the process is long, uncomfortable, and damages the adjacent teeth.

In the not too distant past, the only treatment available for teeth that were dead or infected was extraction. Extraction typically involves gum flaps, sutures and removal of bone to allow complete removal of a tooth. This involves some discomfort for the patient and causes a complete loss of function associated with that specific tooth. For larger teeth, the process of extraction is similar to removing impacted wisdom teeth in a human patient. In the case of a canine tooth (fang), the root is actually much longer than the part of the tooth you can see above the gum line, and a large amount of bone must be drilled away to remove the tooth.

Fractured lower canine tooth with nerve exposed.

Half of the crown of this tooth was broken while playing tug of war.

Final picture after treatment.

Post-operative film, showing the canal and access site now filled.

Root canal treatment is much less traumatic and maintains the normal function of the tooth. Root canal treatment involves drilling 1-2 small holes into the tooth so that the inside of the tooth can be cleaned, sterilized, and then filled with cement and a filling material. This filled space inside the tooth prevents accumulation of bacteria and toxic substances, while keeping the tooth intact. The small holes are then filled with an appropriate restorative material.

While we do not recommend root canal treatment for all dead or broken teeth, many times root canal treatment is preferred to extraction. Certain teeth are more important for chewing, such as the large back premolars and molars. These are large multi-rooted teeth whose roots extend deep into the bone. Saving these teeth can help maintain chewing function and avoid a painful surgical extraction. The canine teeth (fangs) are particularly important to maintain for working dogs and hunting dogs. Extraction of these teeth can weaken the jaw or expose the nasal passages and requires removal of large amounts of bone. Treating these teeth involves less trauma than extraction. Some breeds of show dogs are checked to make sure that they have the correct number of teeth. Extracting a tooth can end their show career. It is acceptable for them to have a broken tooth treated rather than extracted.

Fractured right upper fourth premolar.

This tooth was very painful with exposed nerve tissue.

Appearance after treatment. Restorations are visible (arrows) and the fracture lines have all been smoothed.

Radiograph taken after root canal treatment, showing the filling material in all three root canals of the tooth.

When performed properly, root canal treatment has a very high success rate in veterinary patients.

In summary, root canal treatment is more comfortable for the patient than extraction and can save teeth that would otherwise be lost. It should particularly be considered in the case of important chewing teeth, or in teeth whose extraction would involve removal of large amounts of bone.