Most horses will get through life just fine with little more than regular dental checkups and occasional floating to correct uneven wear. But equine dental specialists also offer a variety of advanced treatments for those with more serious problems. Here are some of the therapeutic dental options available today.
Many horses live quite comfortably with minor malocclusions—misalignments between the upper and lower teeth—but some bite defects significantly impair the ability to chew food. In these cases, orthodontic treatment can be beneficial. "We've started to approach developmental abnormalities from a functional orthodontic standpoint—actually changing the way the teeth interact with each other," says Jack Easley, DVM, author of Equine Dentistry.
For instance, a foal born with an overbite (parrot mouth) or underbite (sow mouth) can be fitted with wires and appliances similar to the braces used in people. The hardware slows growth in the longer jaw while the shorter one "catches up" over the foal's first year. In cases where the malocclusion is so severe that the upper and lower incisors do not touch at all, an orthodontic device can be attached to the foal's shorter jaw to bridge the gap between the two sets of teeth. This encourages growth of the shorter jaw.
These measures are more likely to be successful when applied as early as possible in the foal's growth. In addition, wry mouth—when one or both jaws are shifted sideways so that the teeth do not meet correctly—can sometimes be corrected surgically by fracturing and realigning the jawbones so they will grow properly as a foal matures.
In theory, healthy horses shouldn't be prone to the oral deterioration and tissue loss known as periodontal disease because they don't tend to get food caught in and around their teeth.
"A horse's cheek teeth are designed to be tightly packed together, with no spaces in between," explains Easley. Yet the incidence of periodontal disease in horses is surprisingly high. Surveys conducted over the past two decades show that as many as 40 percent of horses between 3 and 5 years old have some periodontal disease, probably associated with the eruption of their permanent teeth and shedding of caps. Gum disease was found in as many as 60 percent of horses over the age of 15 years. In older horses, the portion of the tooth nearest the gum may be narrower than the rest, leaving a gap that can trap food. Likewise, debris and bacteria can collect in spaces left by missing or broken teeth.
In horses, as in people, prevention is the best strategy. Routine exams enable practitioners to keep the mouth clean and healthy. Frequent cleaning is especially important in horses who already have pockets. In a horse with an advanced case, a practitioner may even enlarge a gap so that food particles can escape.
Horses do not get cavities as people do, but for reasons that are not entirely understood, some do develop endodontic disease (pulpitis), infection of the living tissues inside the tooth. Two factors known to increase the risk of these infections are tooth fractures and the high tooth temperatures generated by overzealous use of power dental tools that are not adequately watercooled. Both may interrupt the blood supply to the pulp and lead to decay.
Extraction was once the only treatment, but infected teeth can now be saved with a surgical procedure similar to root canal therapy in people. With the horse under general anesthesia, a surgeon cuts into the tooth and cleans out the infected portions of the pulp. "You fill them with a variety of materials," says Easley. "But since the tooth is continually erupting, you'll have to go back and redo it in a year or two."
In the past, the only treatment for broken equine teeth was removal, but now many damaged teeth can be repaired or reconstructed. "You can fix a crack in a tooth, depending on where it is, if you catch it early enough," says Easley. "You can bond over the pulp chamber, and since the tooth continues to grow, it can actually heal itself over time, so you don't need to redo the repair."
In addition, broken teeth can be fitted with caps or crowns, and tiny defects can be filled using the same amalgams and resins used in human dentistry. Complete replacement of equine teeth has been attempted but "not with any real practical success," says Easley. Equine dental care has come a long way in the past decade, in large part because researchers have been making great strides in understanding the anatomy of horses' teeth. "We've really moved beyond the gross anatomy?basically the size and shape of the teeth to looking at them with electron microscopes to see more detail of the tooth structure even down to the cellular level," says Easley.
He predicts that greater advances will be made in the very near future. "We are going to see huge changes in the next 10 years," Easley says. "We are in the middle of a paradigm shift and rethinking of our entire understanding of, and approach to, horse's teeth. "Horses will always need to be floated," he adds. "But it's only a very small part of the dental care we can, and should be, giving to horses."