Long in the Tooth

Learn about three dental issues older horses develop that require special care and attention.
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Learn about three dental issues older horses develop that require special care and attention.
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Older horses often have their own particular set of health issues, especially when it comes to dental health. Spend some time watching your older horse eat. Does he leave partly chewed hay wads lying around? Do you see him drop grain from his mouth? Is he taking longer to finish his hay? Is he having problems maintaining weight on his normal feed amount? These are all potential indicators of tooth, gum, or mouth issues.

Horses literally live by their ability to chew. Chewing food properly allows a horse to absorb the critical calories, minerals, and other elements needed to maintain weight, keep a balanced metabolism, have energy, and generally stay well. So, maintaining a healthy mouth that can chew efficiently is crucial-especially as your horse ages.

Facts About Equine Teeth
Horses have two groups of teeth: incisors and canine teeth are in one group, and premolars, molars, and wolf teeth are in the second.

• Incisors are the nipper teeth across the front of the horse's mouth. They function to bite off grasses and hay.
• Canine teeth are right behind the incisors. Aggressive horses still use them today as an offensive weapon, which is why veterinary dental experts will recommend reducing them. Canine teeth are seen mostly in male horses; sometimes mares will grow them, as well.
• Premolars and molars (called cheek teeth) are the larger, squarer teeth at the sides and back of the mouth used for crushing and grinding food.
• Wolf teeth-a prehistoric remnant-sit right before the premolars. Some horses develop them and some don't.

Horse teeth are made of a hard, brittle substance called enamel, and two less brittle materials called dentin and cementum. An interesting thing about horse teeth-which is different from your teeth-is that they "grow," actually erupt, approximately 2 to 3 mm a year. This eruption replaces the tooth that has worn away during the grinding of feeds. Silicates in the grass and hay cause this wear, which amounts to about 3 mm per year.

Tips on Teeth

• Horses live by their ability to chew, so make sure they can chew well into old age by practicing good preventive maintenance from a young age.
• Teeth erupt throughout the horse's life until about age 25. By then, they're often losing teeth due to lack of root/
reserve crown.
• Some dental problems found in older horses are correctable, but others are not.
• Diet modifications may be necessary to help your older horse chew more easily and obtain the maximum benefit from nutrients.

At maturity-that is, when all the permanent teeth are in place at about five years of age-the horse's premolars and molars are about 3 to 3.5 inches in length. Most of this length (called reserve crown) is hidden inside the jaw and skull. Only about one-half to one inch of the tooth is actually exposed (called crown) inside the mouth at any given time.

By the time a horse reaches old age-say his mid-20s-the overall tooth length might have been reduced to less than an inch with very little root or reserve crown left to anchor the tooth in place. The goal of equine preventive dentistry is to maximize the "life span" of the tooth by preventing premature wear due to abnormal wear patterns.

Dental Pain in Horses
Horses can show many different symptoms of mouth and dental pain, some of which seem to have nothing at all to do with their mouths. Additionally, some horses are very stoic. They can have moderate to severe dental or oral problems without showing any signs at all.

Many problems will begin with mild symptoms that can change completely as the disease or abnormality progresses, so owners often think the problem has resolved itself rather than realizing that it has simply changed. So just because your horse is in good body condition and seems to be feeling well doesn't mean that you shouldn't have his mouth checked on an annual basis.

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Potential Signs of Dental Disease
Symptoms of dental disease in the horse are many and varied. And, as mentioned earlier, some signs might not even pertain to the mouth or head, so they can be misleading. Keep an eye out for the following:

• Head shaking or tossing and head shyness
• Creating hay wads when eating
• Dropping feed while eating
• Reluctance to eat or not eating at all
• Facial or jaw tenderness and/or swelling (In two year olds, this can be normal development of teeth known as "tooth buds"; in older horses, this probably indicates dental infection, oral mass, or nasal infection/mass.)
• Bad breath or pus draining from the nose
• Problems when inserting the bit or spitting the bit out, or chewing at or on the bit while riding; reluctance to give and round to the bit
• Behavior problems under saddle
• Weight loss, or in geriatric horses, weight loss followed by no weight gain when additional food is added
• A foamy, frothy mouth and excessive salivation
• Undigested grain or hay in feces

If your horse exhibits any of these symptoms, contact a qualified equine veterinary dentist right away to have your horse's mouth and teeth examined for problems.

Dental Problems in Older Horses
Three dental conditions most commonly seen in older horses are severe malocclusions, periodontal disease, and loose/worn/missing teeth. Here's a rundown of each condition, along with treatment ideas and recommendations.

Severe malocclusions. Jesse Bejar, DVM, of Professional Equine Dentistry out of Littleton, Colorado, notes that one of the most common dental problems seen in older horses is severe malocclusions usually caused by poor preventive care or lack of preventive care throughout the horse's life (especially in the younger and middle years). "Horse's develop malocclusions of some teeth during their youth," Bejar says. "At this age, these malocclusions are easily corrected. If this problem is left unattended, the overgrowths progress and the uneven wear patterns worsen and can become severe. Severe malocclusions inhibit the horse's ability to chew food properly and cause premature loss of teeth. These two factors result in poor mastication of feed and thus lessen the ability of the digestive system to extract nutrients from the feed."

Malocclusions occur in both the incisors and the dental arcades (molars and premolars) along the sides of the horse's mouth. And a horse who can't chew properly is missing out on vital nutrients to keep him going in his older years.

The good news is that your veterinary dentist can make some corrections of extreme waves or ramps or exaggerated bite problems in older horses. The objective is to make them more comfortable. Your veterinary dentist may decide to make the corrections in two or more sessions, so as to be able to determine the rate of eruption of the teeth and not worsen the horse's ability to process feed.

Severe conditions require several corrections, usually every 8 to 10 months for a period of a year or more, and may never be completely corrected due to the slowing of the eruption rate and lack of remaining tooth length available for eruption.

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Periodontal disease. This term refers to any inflammation of the tissues that support the teeth, like the gums, the periodontal ligaments, and the alveolar bone. Dr. Bejar explains that periodontal disease can actually begin in a younger horse. "Periodontal disease is a progressive disease that develops over a period of time, beginning with mild gingivitis (inflammation of the gums). If this is left untreated, it can progress to a more severe stage denoted by receding gums and exposed reserve crown and tooth roots and infection. Infection may necessitate tooth extraction."

Periodontal disease can have many causes, including: poor preventive maintenance throughout the horse's life; food packing into spaces between the horse's teeth, which can breed bacteria; and possibly diets high in grain or sugars.

If your older horse does develop periodontal disease, your veterinarian has a few limited treatment options. Dr. Bejar explains: "If the periodontal disease is caused by feed packing into gaps in between teeth (called diastema), we actually widen the gap even further so feed can't get stuck in the space. The more advanced cases of disease seen in elderly horses usually require tooth extraction-which is why we prefer to prevent it in the first place."

Technology is becoming available that will allow veterinary dentists to treat the more severe cases of periodontal disease and reduce the number of cases in which they have to extract teeth. No research has been done to prove that horses experience many of the adverse systemic reactions to an infected mouth that are seen in other species-such as heart, liver, and kidney problems.

However, it's likely that the systemic effects of oral infection seen in humans and small animals also occur in horses. Additionally, untreated inflammation and infection can be painful, so addressing periodontal disease is a must to keep your old friend well.

Loose/worn/missing teeth. Horses' teeth become loose for many reasons: trauma to the mouth; issues with the supporting structures (as with periodontal disease); and short roots, as you'll find in older horses. Ironically, the expression "long in the tooth" was originally used to describe older horses, who typically have very long incisor teeth due to the receding gum line.

"As a horse ages, the incisors slant progressively forward, so that more and more of these teeth become visible. The expression cannot be applied to the premolars and molars of an older horse, but it certainly describes his incisors," notes Dwight Bennett, DVM, PhD, professor emeritus at the College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins.

As mentioned earlier, a horse has about 3 to 3.5 inches of tooth at maturity, and this tooth erupts out of the jaw or skull over the horse's lifetime. By the time a horse is in his 20s, he may have less than an inch of tooth left. Without a firm anchor, these teeth can become loosened or even fall out.

"In younger horses, loose teeth will sometimes re-seat themselves and establish connections within the tooth socket," says Dr. Bejar. "But more often in older horses, it's best to extract these teeth."

Since an extraction will leave a hole where the tooth was, it's important to have your horse's mouth examined regularly afterward. Food can pack into these new spaces, and the opposing teeth can overgrow when they have nothing to wear against (step mouth), causing another malocclusion.

Diet Modifications
Keeping an eye on how your old horse chews his food can help you decide when the time may be right to modify his diet to accommodate dental issues. Dr. Bennett notes that "Horses are easily living into their 20s nowadays. Even if you've kept abreast of dental maintenance throughout your horse's life, he still may need a special diet to allow him to get the maximum nutrition from a source other than pasture forage or hay." All of the major food manufacturers produce pelleted foods formulated specifically for senior horses.

These soft, pelleted diets are easy for elderly horses to chew and can be used as the main food source (if labeled "complete diet"), removing hay from the picture entirely. "Offering hay to older horses with poor dental health can cause even more problems," notes Dr. Bennett. "If a horse swallows enough hay without chewing it well, it can cause an impaction in the intestine, which in itself can be life-threatening."

Make diet changes for your old horse only after consulting with your veterinarian to help you find the best choices.

Gentle Dentistry
As you've seen illustrated here, older horses generally have more fragile mouths than younger horses. You may wonder if you should discontinue having work done on your older horse's teeth in an effort to prolong the life of whatever teeth may remain. Maintaining your old friend's dental health continues to be essential, but you may want to talk with your equine veterinary dentist about his or her use of electric tools versus manual tools.

"Power tools continue to be one of the best innovations in equine dentistry," notes Dr. Bennett. "But they need to be used very carefully in older horses."

In inexperienced hands, it's easy to destroy a tooth using power tools. The practitioner can take off too much tooth or even kill a tooth by overheating it. In an old mouth that may already have loose teeth, malocclusion issues, and periodontal disease, gentle and careful use of electric tools actually can help to prolong the tooth life by making corrections easier to perform and more exact.

"I use my specialized power tools on older horses all the time," notes Dr. Bejar. "I can make corrections more quickly and effectively than I could with hand floats, which translates to less time that the mouth is open, and thus less stress and pain on the joints of the jaw." Ultimately, this will be easier on your old horse.

Those of us who are blessed to know the spirit and soul of an old horse know that we'd do anything to keep them well. By carefully following exam schedules and maintaining your older horse's dental health, you can enjoy your perfect old horse for years to come.