Equine Dentistry: Beyond the Basics

High-tech equipment and techniques are helping veterinarians provide better equine dental care.
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High-tech equipment and techniques are helping veterinarians provide better equine dental care.

The horse’s mouth is a complex functioning unit. Says Mary DeLorey, DVM, who cares for patients throughout Washington and Western Idaho with her ambulatory Northwest Equine Dentistry, “All the tissues of the mouth function as parts of that unit, and each is integral to overall dental health–and to health in general.”

Thus, a detailed oral examination is an essential part of any horse’s annual checkup. A normally wearing “arcade” of healthy teeth enables the horse to ingest and begin processing nutrients appropriately. So maintaining that arcade is a prime focus of equine dental care–and a major reason for a thorough yearly exam.

But floating the teeth shouldn’t be the examining veterinarian’s sole focus. As we’ll explain in this article, advances in instruments, imaging technologies, and surgical techniques are allowing veterinarians to examine and understand all parts of that complex unit better, and to diagnose and treat dental problems more effectively.

Open Wide

A full-mouth speculum is the standard device veterinarians use to keep a horse’s mouth open for examination. Jack Easley, DVM, MS, Dipl. ABVP, who operates Easley Equine Dentistry as part of his Shelbyville, Ky., general practice, remembers when practitioners used general anesthesia before introducing a speculum, because “the only restraint capability we had was a twitch, and the speculum was brass and weighed 40 pounds–dangerous if the horse started swinging his head around.”

He considers today’s mild sedatives to be major breakthroughs for veterinarians practicing equine dentistry. “The horse just stands and watches, so your movements can be planned and precise,” he says. Both Easley and Delorey say they routinely sedate horses with these drugs before beginning mouth exams.

Today’s speculums are considerably lighter than they were decades ago. Althought their design has remained essentially the same, Delorey says, “small changes in mechanics and materials have provided increased safety and options for specific applications. Some speculums have more metal, some less. The one I use while taking X rays contains very little metal, so it distorts the X ray beam less.”

With the speculum in place, the veterinarian uses his or her eyes and hands to search for debris wedged in or between teeth and for problems with the teeth themselves–including sharp enamel points (normal byproducts of chewing-caused tooth wear). Smoothing these points so they don’t cut the horse’s cheeks or tongue is what’s meant when someone says “floating teeth.” (As an aside, Delorey says veterinary dentists are trying to move away from that term because it has no agreed-on definition. To some people, “floating” covers anything that needs to be done in the horse’s mouth.)

Veterinarians have long used hand-powered steel rasps to remove such points. Additionally, Easley says, tungsten-carbide rasps with very sharp, fine blades make cutting faster and more precise and require less effort when removing dental points and crown elongations. Motorized rasps also remove more material in less time with less effort.

When these tools first became available, “some veterinarians started doing dramatic recontouring of horses’ mouths,” Easley says. “We’ve since come to understand that dramatic changes can cause damage. Teeth are living structures; horses feel heat and cold and pressure differences on their teeth as we do on ours. So if a horse has a major malocclusion or an abnormal wear problem, we don’t try to correct everything at once. Instead, we stage the correction: doing a little bit at a time, coming back every few months. Over a year or two the horse gets back to having a really good mouth, without undergoing any major readjustments.”

Imaging Advances

Even the sharpest eyes and most sensitive hands can’t detect problems far back in the mouth, gums, or within the teeth. Improved imaging technology has greatly expanded veterinarians’ ability to find and analyze such unseen problems. With portable imaging technology, plus imaging-supported detailed studies of how teeth change over horses’ lifetimes, Easley says, “we understand dental pathology better. We can detect whether something is a true abnormality or just a variation of ‘normal,’ and we can intervene early enough to relieve discomfort and prevent tooth loss.”

Digital radiography–X ray imaging that involves using digital sensors instead of traditional film–is “probably the most common tool we use to diagnose pathology,” Delorey says. “There are two general kinds, referred to as ‘DR’ and ‘CR,’ available to the veterinarian in the field.”

DR means direct radiography. “It’s a rigid sensor that’s hard-wired to your computer; the second you hit the trigger on the X ray generator, the image shows up on your monitor,” Delorey explains.

CR stands for computed radiography. It’s also fully digitized but requires one extra step: “The X ray generator exposes a flexible plate, which then gets run through a scanner; the image, instead of appearing immediately, takes probably an extra 30 seconds,” says Delorey. “The plate lets us take an intra-oral X ray, showing an individual tooth or a couple of teeth inside the mouth (just as those little plates that hurt the roof of your mouth let a dentist see particular views of your teeth). This approach allows for very detailed imaging. It’s becoming more standard as part of a diagnostic work-up when there’s indication of a dental problem”

While veterinarians aren’t using CR for dentistry as commonly as DR, the technology is relatively inexpensive. Many equine dental practitioners have CR units and routinely use them in the field.

Easley notes that the improved imaging equipment isn’t so much the advancement as is the quick consulting it affords. He says both kinds of digital radiography allow the veterinarian in the field to take a radiograph, look at it, and (if need be) reposition the unit and take another for a better look. “It’s exponentially changed our ability to diagnose–and the accuracy of our diagnoses,” he says.

Computed tomography (CT) provides even more detail, but in a 3-D image, which is very useful in complicated cases, such as sinus infections secondary to -infected teeth, notes Easley. The imaging modality is expensive; most CT scanners capable of imaging horses are located at veterinary schools, and all such units in the United States require the horse to undergo general anesthesia. “It’s not a terrible drawback,” Easley says, “because a CT scan takes only 30 or 40 minutes.”

Easley notes that in Europe practitioners have access to at least three standing CT units. These allow the horse to remain standing in the stocks without anesthesia (although sedation is likely necessary) while his head is scanned.

Nuclear scintigraphy (bone scan) is another imaging technique that practitioners can use to diagnose mouth problems, Delorey says, but it, too, is expensive and largely confined to university settings. “So in most cases we rely on standard digital radiography,” she says. “But if something’s not clear from digital imaging, CT or nuclear scintigraphy may be helpful.”

Surgical Advances

One of equine dentistry’s major recent advances is the ability to perform complex procedures, such as tooth extractions, in standing patients with less trauma and reduced complication rates.

“In many cases today, we can successfully treat a tooth that’s injured or diseased,” Delorey says. “Or, if we do have to extract it, the effort may not need to be so invasive. Laying a horse down and forcibly removing a tooth with a hammer is really a last resort–and unnecessary in probably 90 percent of cases.”

Thanks to techniques such as laparoscopy and arthroscopy, Easley says, dental surgery has and continues to evolve: Practitioners are “making fewer big incisions and instead going through smaller incisions to manipulate things. For example, if a tooth needs treatment, the veterinarian might make a single incision through the cheek near the tooth, insert a trocar (a tube that’s a bit like a drinking straw or a big hollow needle) at the incision, and work on the tooth with instruments inserted through the trocar. For teeth back beyond the incisors or canines, a cheek incision provides much easier access than going in through the front of the outh.”

On the Horizon?

Because horses’ teeth are structurally different than humans’ teeth, veterinarians can’t assume that repair strategies from human dentistry will work for horses. Research is under way, particularly in the areas of endodontic therapy (root canal work) and cavity fillings. But Delorey cautions, “Yes, we can do fillings, and some root canals–but the fact that we can do something doesn’t necessarily mean we should do it. So far, we have very little data on how effective either procedure is, or even how useful.”

Easley agrees that veterinarians are not yet ready to apply these particular teeth-salvaging strategies widely. But he’s hopeful that within the next few years they will have some solid evidence-based, proven techniques to offer clients.

Take-Home Message

Veterinarians all over the United States are successfully treating very complicated dental pathologies. When your horse gets that annual checkup, “encourage your veterinarian to examine the mouth thoroughly,” says Easley. “If he or she isn’t comfortable doing that–and not everyone is, just as not everyone is comfortable doing reproductive work–seek a consultation with a veterinarian more experienced in dental care. There are plenty of things we can do to help horses with bad teeth live long and productive lives, but the first step is identifying and diagnosing the problem.”

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Written by:

D.J. Carey Lyons is a lifelong resident of Chester County, Pa. She also has written for USDF Connection, Practical Horseman, Equine Images, and Dressage & CT.

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