When your older horse’s pearly whites are past their prime, keep an eye out for signs of specific problems and schedule frequent dental exams.

Decades ago horses didn’t live past their teeth, and we thought of equids in their teens and early 20s as old. “Now, with improvements in health care and diet, we can feed these older horses beyond when their teeth wear out,” says Melinda Freckleton, DVM, of Haymarket Veterinary Service, in Virginia. “But we have to be more proactive in taking care of their dental needs.”

Equine teeth continually erupt from the jaw to compensate for normal wear. As time passes, the amount of reserve crown (the portion of the tooth within the jawbone that has not yet erupted) decreases; eventually, the senior horse simply runs out of tooth. Teeth also change shape and angle as they move outward, potentially promoting uneven wear.  

Some senior horses show clear signs of dental problems, such as an inability to eat properly, but other signs are less obvious. “I have to remind people that a fat, shiny old horse still needs his teeth checked,” says Freckleton. There might be problems developing—such as gum infections, fractured teeth, or sharp points—that owners can have their veterinarians address before the damage is too great.

Signs of Dental Problems

As a horse ages, his owner should watch for changes in the way he eats, such as eating more slowly or reluctantly, moving food around in his mouth more than usual, or quidding (dropping wads of partially chewed food out of the mouth). If a horse tips his head or holds it sideways, particularly while eating, he might be trying to avoid putting pressure on a painful area. Weight loss can also be a sign of dental problems, if pain is preventing a horse from chewing properly and eating enough.

Bad breath might indicate an infection within the mouth, and nasal discharge—particularly on one side—can indicate sinus problems due to dental issues, says Freckleton.  

“Mild diarrhea or fluid alongside normal manure can be a sign of dental problems,” she adds. “If horses are not chewing hay completely, long fiber length can irritate the gut. The owner may call because the horse is passing fluid in the feces and is surprised when I check the teeth, among other things.”

Common Problems

According to our sources, dental issues commonly seen in older horses include:

Lost teeth

If a horse loses a tooth, the opposing tooth has nothing to wear against. “You have to manage those tall teeth because horses’ jaws move in a circular motion, side to side,” says Bruce Connally, DVM, who practices equine dentistry in Buffalo, Wyoming.  

He says when the opposing tooth catches in the space where there was once another tooth, the horse’s jaws can lock up and prevent the horse from completing that circular chewing motion. This can cause considerable pain in the horse’s temporomandibular joint (TMJ, which allows for opening and closing of the horse’s mouth), further affecting the way he eats. 

Infection

Loose teeth, expanded spaces between teeth, or fractured teeth might lead to gum infection, tooth root infections, or openings where pathogens such as bacteria might enter and infect the sinuses. Veterinarians see this more frequently in older horses with equine Cushing’s disease because these animals’ immune systems are compromised. Thus, they need frequent and proper dental care to prevent or treat potential tooth infections. “Sinus infections in general are not easy to clear, and if the horse is immune-compromised it makes this even more difficult,” explains Claudia True, DVM, of Woodside Equine Clinic, in Ashland, Virginia.

Freckleton notes, “Generally if we find infection in the horse’s mouth we treat it with antibiotics or extract the affected tooth. For most horses this gives them the quickest and most effective relief, with a good outcome.”

Wave mouth

This problem is characterized by a series of tall and short teeth on one arcade (row of cheek teeth). “We don’t know exactly why wave mouth occurs,” Connally says. “Maybe there was a soft tooth that wore out more quickly. Severe wave mouth can lock up the jaws and make it difficult to chew. Mild wave mouth isn’t a problem, and some people argue that it’s not pathologic (disease-causing).”

Depending on the severity of wave mouth, you might need to make some feed management changes to help the horse chew. Inability to chew properly not only affects feed efficiency, nutritional status, and comfort but also increases the risk for other problems such as choke or impaction colic in some horses. “If fiber lengths of forages are too long and not broken down enough, horses might have a harder time moving them through,” says Freckleton. “It won’t be a direct cause of impaction but can certainly affect a horse’s risk.”

Sharp points and hooks

If an equine dentist identifies sharp tooth points, he or she will file down or remove them to make eating more comfortable for the horse. Connally notes that in older horses she frequently observes a very tall hook on the front or the back cheek teeth (molars), because the jaws don’t match up properly. “Part of the tooth wore off and the rest didn’t,” she says. Those hooks can become very long and painful, particularly if they come into contact with the gingiva (tissue immediately surrounding the base of the horse’s teeth) on the opposite jaw. In these cases the horse can’t close his mouth without that hook poking into the jaw and its sensitive tissues.

Food between teeth

Sometimes food packs into the periodontal pockets between senior horses’ teeth. “If the horse is packing feed between the teeth, I may have the owner flush the mouth periodically and pay attention to how the horse is chewing so that if anything changes I can come before the next scheduled exam,” True says. “Sometimes we need to clean up those periodontal pockets, pack them with antibiotic, and put dental impression material over it, to keep feed from packing in there and allow it to heal.”

Other times, the veterinarian might discover the surrounding tooth or teeth are loose while cleaning out the pockets. In this instance, removing the tooth is the best solution. “After that, we have to periodically reduce the opposing tooth so it doesn’t become too tall (and cause the chewing problems described earlier),” True says. “We usually need to check this every six to nine months.”

Incisor problems

We tend to think of cheek teeth (the grinders) as needing the most dental care, but incisors sometimes develop problems if they are mismatched, broken, or lost.

“The horse can chew hay if the molars are normal, but can’t bite off short grass if his incisors have a problem,” Connally says. “If the horse is always fed hay, you may not notice.”  

Have your veterinarian give the incisors a once-over during these routine exams to pinpoint any subtle problems.

Equine odontoclastic tooth resorption and hypercementosis (EOTRH)

Veterinarians have only identified and named this condition, characterized by resorptive lesions (similar to cavities in humans) of the incisors and, sometimes, canine teeth, in recent years. The disorder develops primarily in older horses and usually appears gradually, going undiagnosed until lesions are quite extensive.

  “You might notice that the incisors are becoming a little loose,” True says. “The horse might not want to bite into a carrot because those teeth hurt. In later stages, the teeth become crooked. On X rays a normal incisor would appear as a smooth, long tooth that tapers toward the end. With EOTRH the tooth looks fairly normal on the surface, but underneath the gum it may be large and bulbous. Unfortunately this disease is progressive, and we haven’t found a good way to treat it other than extracting the teeth,” which she reports has provided relief in all the cases she’s treated.

To date, researchers have not found this disease’s cause, so they don’t know how to prevent it, but impacted animals can be managed successfully. “If we can identify it early, we can take radiographs and start extracting teeth if we need to,” says True. “Owners often worry about a horse losing the front teeth, but it’s amazing how well these horses manage. I’ve had to take out all the incisors on some horses, in stages, and those horses go back to grazing (using their lips) and are much happier because they are not living with chronic pain.

“The horse’s tongue may hang out sometimes, however, when the horse relaxes,” she adds, noting the slight cosmetic drawback. “The front teeth are no longer there for the tongue to rest against.”

Maintenance

Most old horses require more frequent dental checkups than their younger counterparts. “As the teeth age, I feel it is important to do twice-yearly dental exams,” says Freckleton. “It doesn’t have to be extensive or expensive. A quick look in the mouth, using a speculum and a good light source, and a good feel around could alert you to problems that might be developing.”

Connally advises practicing selective floating (smoothing only the sharp enamel points of the teeth described earlier). “The horse’s mouth should dictate what is done,” he said. “Every horse is different. I am a firm believer in routine exams but not necessarily routine treatments.”

When performing a dental exam, the practitioner might use a full-mouth speculum to examine the teeth.  

“In my experience, the older horses generally tolerate a speculum,” says Freckleton. “There are some exceptions, and horse owners need to be aware that we might have to sedate the horse (for safety). Also, sedation may be necessary if there is arthritis in the temporomandibular joint and it’s painful for the horse to open his mouth that much.”

She adds that owners need to remember that horses’ teeth are unlike human teeth. “Most of the common dental procedures for horses are not painful and a veterinarian can provide pain medication when necessary,” she explains. “Horses also don’t suffer the emotional and anxiety-related (dental) phobias that people do.”

Take-Home Message

Older horses are prone to a variety of dental problems, such as sharp points from uneven wear; loose, lost, or broken teeth; and various infections. Frequent checkups allow the veterinarian to detect concerns that can be managed to make the horse more comfortable or to head off a more serious issue.