Equine Dentistry Discussed


"Dental Concerns of Older Horses" was the focus of one lunchtime Table Topic, with subjects ranging from diet selection to systemic illness to sedation. With veterinarians filling all seats and standing against the walls, discussion was lively at times.

"Don't be too quick to assume that if an old horse is in bad shape, it's because of his teeth," said one attendee, noting that several systemic conditions can cause weight loss in the older horse. Another reported success with systemic antibiotics in a thin, older horse with mouth sores; the horse had low-grade septicemia (bacterial infection in the blood).

Diet ingredients were discussed with the obvious emphasis on feeds that are easy for a horse with poor teeth. All pellets aren't created equal, said one attendee; some are rock-hard and require hard chewing (many old horses cannot effectively chew these hard pellets), while others break down very quickly in saliva. Another recommended using a complete feed for older horses with trouble keeping on weight. One moderator, David Foster, VMD, of New Jersey, recommended that a veterinarian be called to examine any old horse which suddenly begins to lose weight. Another attendee suggested that when evaluating older horses, veterinarians should ask to see a sample of the horse's feed so he/she can recommend changes, if necessary.

Foster discussed flushing a horse's mouth with a weak chlorhexidine (a disinfectant) solution for horses with severe oral hygiene problems, and noted that doing this once a week for the rest of the horse's life can help keep his mouth in better shape for years to come.

Tooth Wear

"Most dental problems stem from chronic stress on the tooth," said the other moderator, Jack Easley, DVM, MS, Dipl. ABVP, a private practitioner in Shelbyville, Ky. "I think we need to change the way we think about a lot of dental problems. The abnormal wear often is not the problem--the long tooth is often the healthiest tooth with nothing keeping it from erupting correctly. If we straighten out (shorten) this tooth, we completely ignore what the pathology is (in the other teeth)."

He added that young horses' dental problems generally stem from poor eruption of teeth, while geriatrics' dental woes often result from the narrower deep ends of the teeth erupting, resulting in gaps between teeth. "Additionally, all horses eventually run out of reserve tooth," said Foster.

Gum pockets (periodontal disease) around the teeth are relatively common in these geriatric horses as well. Easley noted that packing these pockets (after cleaning) with antibiotic packing such as Doxi-robe to promote healing can be successful, but it's tough to get it to stay there.

Sedation and Restraint for Dentistry

Several practitioners agreed that it's best to put the older horse in a corner for dental work, to make sure he's against a wall for leaning, and that these horses are often more comfortable if you work on them with their heads low. Proper sedation can also help make the procedure quicker and easier on horse and human.

Several practitioners explained their use of yohimbine to reverse sedation once they are finished with a horse. One noted that when the horse is waking up, he will often eat more boldly, so the handler should make sure the horse does not ingest something inappropriate.


"We now look and are able to see more clearly," said Easley about the use of open-mouth radiographs in the field to understand equine dental problems. In his presentation, "A New Look at Dental Radiology," Easley discussed how open-mouth radiographs can be invaluable tools for the equine practitioner in the diagnosis and treatment of all types of dental abnormalities. He believes that radiology has not been used enough in the field by practitioners.

"Open-mouth films bring the upper and lower occlusal (biting/grinding) surfaces out of contact and decrease superimposition (overlay) of the right and left arcades (rows of teeth)," he said. This technique can allow the practitioner to see the entire circumference of the tooth crown, which was previously obscured.

Heavy sedation is necessary for about 20-30 minutes for safety during radiography and to help open the horse's mouth. Sedation allows the horse to be more comfortable and allows the veterinarian to perform a more detailed exam. The horse's head is rested on a table or support stand to help achieve motionless radiographs. Easley recommends making this a routine part of equine dentistry.


The use of power equipment in the field of equine dentistry has been a great aid to equine practitioners. One advantage is that it lets the practitioner complete major dental correction before sedation wears off. But could these power tools harm horses' teeth? According to a recent study done by Gordon Baker, BVSc, PhD, MRCVS, Dipl. ACVS, of the University of Illinois' College of Veterinary Medicine, power tools could damage teeth. In his presentation, "The Use of Power Equipment in Equine Dentistry," Baker discussed the advantages, potential disadvantages, and guidelines for the efficient use of power equipment in equine dentistry.

The use of power equipment reduces the risk of tooth fracture, there is less labor involved for the veterinarian, procedures can be done more quickly, there are superior end results, and the practitioner has a reduced workload, according to Baker.

In human dentistry and in animal models, it has been shown that crown reduction with power equipment generates heat in the tooth. An increase in pulp temperature of 5.5°C causes irreversible damage in 15% of the human teeth tested. Another study showed that an increase in pulp temperature of 16.3°C resulted in pulp necrosis (death) in 100% of the teeth that were examined. Damage from thermal pulp injury might not be seen for one year, said Baker. It has been determined that an increase of 5°C is the highest safe increase before damage occurs. Since all hypsodont teeth (long teeth that wear away throughout the animal's life) need living pulp, this could be a problem for the horse.

Thirty equine teeth were divided into three groups for the study (in a laboratory setting). Group one underwent a one-minute reduction using a disc burr power floating system. Group two underwent a two-minute reduction. Then the experiment was repeated with both groups undergoing reduction for the same amount of time with water irrigation. Thermocouples were used to measure changes 15 mm from the biting surface of the tooth (proximal) and 25 mm from the biting surface of the tooth (distal) at the level of the pulp chamber.

The one-minute reduction showed an average 6.6°C rise in temperature at the proximal thermocouple and an average 1.2°C increase at the distal thermocouple. The two-minute reduction produced a 24.3°C and 4.06°C increase, respectively. Thermal increases continued for two minutes after the work was stopped for group two. During the repeat reductions, application of water for cooling negated all heating effects of the power tool.

The two-minute reduction was the equivalent of major hook and ramp correction, crown or incisor reduction, or bit seat construction, said Baker. Results from the study indicated that these procedures could cause pulp trauma. Therefore, intermittent contact time and cooling irrigation are recommended.

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