By Lyn Gunville
Findings from a baseline dental study at the Western College of Veterinary Medicine (WCVM) emphasize the need for horses to have their teeth examined by a veterinarian at least once or twice a year — particularly as horses age.
During the summer of 2008, veterinary dental specialist Dr. James Anthony and veterinary student Amanda Laycock examined the oral cavities of 556 horse cadavers at a livestock slaughter and processing plant near Neudorf, Sask.
A significant factor of the study was that it included horses of a wide variety of ages and breeds from all over Canada and the United States. “Prior equine dental research — particularly in North America — has never included such a diversified population base,” says Anthony, an associate professor of veterinary dentistry at the WCVM.
With the goal of directing future research, Anthony and his team set out to identify the most common oral pathologies in the horse. Besides Laycock, Anthony’s research team included large animal epidemiologist Dr. Cheryl Waldner and veterinary dental resident Dr. Candace Grier-Lowe.
The Peter Emily International Veterinary Dental Foundation provided a $5,000 grant for the study while Laycock’s four-month research position was funded by the Interprovincial Undergraduate Student Summer Research program.
The study’s major finding was the prevalence of sharp edges on the teeth: nearly half (47.7 per cent) of the 556 horses had this pathology. “If you have sharp edges on the premolars, there’s definitely oral pathology,” says Anthony who explains that horses move their mouths laterally when they grind their teeth, causing those sharp edges to lacerate the cheeks and tongue.
That fact was reflected in this study where horses with sharp edges were 112 times more likely to have buccal (cheek) abrasions and 3.6 times more likely to have lingual (tongue) ulcers. The prevalence of sharp edges on teeth along with the associated abrasions and ulcers on the cheeks and tongues was higher than Anthony expected: “We never even came close to expecting those kinds of numbers.”
Anthony also found that pathology increases with age and was surprised by the high incidence of periodontal disease, particularly in the older animals. Conditions such as abscesses can develop from a periodontal pocket, a diseased space between the gum and the tooth, or an endodontic lesion, the result of bacteria getting into the exposed pulp of a broken tooth. These abscesses cause pain and discomfort, and there’s evidence that they may also lead to systemic problems such as heart and kidney disease.
In the study, horses between 15 and 20 years of age were 18.9 times more likely to have periodontal pockets than horses aged one to 4.5 years old while horses 20 to 30 years old were 42.7 times more likely to have periodontal disease than the younger age group.
The prevalence of missing teeth was another important finding. Anthony explains that horses’ teeth are arranged side by side in columns, and a missing tooth leads to irregular wear and abnormal shaping of the opposing tooth. These conditions — called ramps and waves — can cause pain and restrict the regular grinding motion of the teeth. This can impair the eating capabilities of the animal and lead to eventual weight loss.
Based on the study’s results, Anthony is adamant about the need for regular, thorough oral examinations and for further research into equine oral health. “The major benefit is basically for the health and welfare of all horses,” says Anthony. “There are things we can do to make their lives better, and we can focus our research so that we help these horses get better
and have a more productive, happier, comfortable life.”
Although oral examinations require sedation, Anthony emphasizes that the benefits definitely justify the procedure. He points out that when people go to their dentists, everyone expects a thorough evaluation. The same idea applies to horses: “Instead of just opening the mouth and smelling and looking at the mouth, the veterinarian needs to do a lot more than that,” says Anthony.
“The animal should be sedated and each tooth checked using dental picks, probes and mirrors in order to find the problems.”
A major accomplishment of the study was its identification of the specific areas requiring more research. “There’s a whole range of different areas that we need to investigate. Periodontal disease and looking at how to treat it effectively in a horse — that’s a major concern. There are many ways of addressing it, but which one’s the best?”
Anthony also hopes for more development in endodontics. For example, root canals could be done on horses, just as they are in humans, and would result in saving a tooth rather than pulling it out. Implantology of teeth is another area of interest and could be used when a tooth has been extracted or to fill the space between two teeth. He points out that these research projects are still in the designing stages and a lot of the projects could require years to show results.
A paper documenting Anthony’s baseline study is scheduled for publication in the Journal of Veterinary Dentistry. During the past few months, the WCVM specialist has presented his findings at the European Veterinary Dental Congress in Zurich, Switzerland, and at the Annual Veterinary Dental Forum in Scottsdale, Ariz in Scottsdale, Ariz
Tooth Study Team
• Dr. James Anthony (WCVM Department of Small Animal Clinical Sciences): associate professor, veterinary dental specialist and the study’s principal investigator.
• Dr. Cheryl Waldner (WCVM Department of Large Animal Clinical Sciences), professor of epidemiology. Waldner provided statistical expertise for the project.
• Dr. Candace Grier-Lowe (WCVM Department of Small Animal Clinical Sciences): veterinary dentistry resident. Grier-Lowe helped with data collection and assisted with statistical analysis.
• Amanda Laycock: third-year veterinary student who helped with the study’s groundwork, assisted with statistical analysis, and helped write the research paper. Her position was supported by the Interprovincial Undergraduate Student Summer Research program. Visit www.ehrf.usask.ca to read more about Amanda’s summer research experience.
• The Peter Emily International Veterinary Dental Foundation: organization that supports veterinary dental services, education and research. The foundation granted $5,000 to the WCVM dental project. Visit www.peteremilyfoundation.org for more details.
• Natural Valley Farms: allowed the WCVM team
• Natural Valley Farms: allowed the WCVM team to carry out the research study at its slaughter and processing facility near Neudorf, Sask. The Saskatchewanbased company also provided information regarding gender and weights of the animals included in the study.
• Canadian Food Inspection Agency: CFIA veterinarians and inspection staff assisted the WCVM research team during their time at Natural Valley Farms.