Advanced trends in veterinary dentistry (Proceedings)
The field of veterinary dentistry has changed rapidly in the last few years. Dentistry in the veterinary clinic is no longer limited to teeth cleanings and extractions. The pet has become a family member, so the client has come to expect more from the veterinarian. It is becoming important that the veterinarian in a general practice be aware of what options are currently available to the client in need of veterinary dentistry. The veterinarian should know what procedures can be done to save fractured or damaged teeth. Extraction may not be the only option.
Not all fractured teeth require extraction. If the fracture is not into the pulp canal, an odontoplasty can be done to smooth the fracture site. A sealant or composite restoration could also be applied to the fracture. If the fracture is into the pulp canal, the options are extraction, vital pulpotomy and root canal therapy.A vital pulpotomy can be done if the fracture is very recent, less than 48 hours. This procedure is to try to keep the tooth alive and vital. A small amount of the pulp is removed and replaced with calcium hydroxide or a product called MTA. This is to hopefully stimulate the vital pulp to lay down a secondary layer of dentin, and keep the tooth alive. The tooth must be closely monitored to be sure that it remains vital. Dental radiographs should be done every 6 months to a year. The pulp canal should get smaller as the vital tooth ages. The apex of the tooth should be monitored to make sure that an abscess in not forming. The client should be advised that a root canal procedure may need to be done in the future.
Root canal therapy
Root canal therapy is done when a tooth has been fractured for a period of time. When a tooth is fractured into the pulp canal, the pulp is contaminated with bacteria. If not addressed very soon, the bacteria contaminate the entire pulp. Often the fracture site will seal with plaque and debris, the bacteria will then multiply and kill the pulp. The multiplication continues and will abscess out the apical delta of the tooth. Often a facial swelling will occur. It may take months to years for this to appear. An apical abscess can often be seen on a dental x-ray much sooner. Antibiotics will reduce this swelling temporarily, but will return when antibiotics are discontinued. The root canal procedure will maintain the integrity of the tooth.
An opening to the pulp canal is made into the crown to provide a straight line access to the apex of the tooth. Using endodontic files in increasing size, the pulp is removed. The canal is flushed with a dilute bleach solution, followed by hydrogen peroxide several times during the filing stage. When the canal is sufficiently cleaned, paper points of the proper size are used to dry the canal. A Zinc Oxide/Eugenol (ZOE) mixture is then applied to the pulp canal. The bulk of the ZOE is the removed. The entire canal is then filled with gutta percha to force the ZOE into the dentinal tubules. This product is a hard rubber like product that when warmed can be and packed into the pulp canal to force the ZOE into the dentinal tubules. It is very important that the apex be totally sealed to ensure that the apical abscess will not return.
Intra-oral radiographs are taken throughout this procedure to make sure the proper filling of the canal and to make sure the apex is sealed. The access opening is then closed with a light-cured composite.
This procedure is radiographed in six months to ensure that the apical abscess is resolved. At this time if the apical abscess is resolved, it may be necessary to have a metal crown made for the tooth. This usually requires two steps. The tooth is prepared for a crown, impressions and models are made in the first step. These impressions and models are then sent to a dental lab to have a metal crown made. The second step is placing the crown onto the tooth with an adhesive designed for this purpose.
There must be enough tooth structure available to support the metal crown. The crown will not be the original length of the tooth; it will cover the remaining tooth. The outside layer of the tooth will be shaved down roughly the width of the crown wall to just above the gingival line. This allows a smooth transition from tooth to gingival margin, not providing a surface for plaque to adhere.