12/19/2002 Entry: "Holistic Husbandry"

Article from The Whole Horse Journal, February 2000
DO Look in Your Horse's Mouth

Proper dental care entails far more than simply "floating" the teeth.

ARTICLE AND ILLUSTRATIONS BY BARBARA CHASTEEN

Dana was in decline. A big, beautiful cavalry-style Morgan who once enthusiastically traveled thousands of trail miles, he had become a grouch. His neck stayed tense no matter how much chiropractic or massage he got. He couldn't walk straight, his back hurt, he was always a little thin. Mostly he stood in his paddock, leaning heavily on his forehand to alleviate the pain of arthritis in his hocks, which didn't respond to Bute and light exercise, steroid or hyaluronic acid injections, or any other therapy. At 15 years hold, in what should have been the prime of his life, he seemed laid up for good.

Dana's dramatic recovery began when his owner hired a technician specializing in equine dentistry. Over seven years, four different veterinarians had "floated" his teeth, checking for sharp points and filing them away. But not one veterinarian noticed that the gentle gelding chewed with an up-and-down movement (instead of a normal side-ways motion) and that he sometimes drooled slightly. By the time the dental technician examined his mouth, Dana's lower molars were so long that they had punched quarter-inch holes into his upper jaw. Left unattended, the "spikes" might eventually have punctured the artery in the palate and caused him to bleed to death.

With these spikes cut and his incisors shortened, Dana was able to chew normally. His eyes brightened and his neck relaxed into its inborn graceful curve. For the first time in years, he had to start watching his weight, although his feed intake was cut at least in half!

Most amazing of all of Dana's changes was the immediate reaction of his hocks. As the chronic tension he displayed in his jaw and neck was released, his back, hocks, and stifles relaxed, and he was able to stand and move without pain. After a period of recovery and fitness training, he returned to work on the trail, and now gallops out to pasture like a colt.

Many horse owners have discovered how equine dentistry can make a difference in their horses’ health and performance. For some horses, like Dana, proper dental work can even give them a whole new life.

A dental difference

Dental technicians are trained to evaluate the condition of every tooth and the balance and performance of the mouth as a whole. They use a "speculum," a specialized halter that holds the horse's mouth open to allow complete, safe examination. After the evaluation, a professional dentist will discuss an overall treatment plan and cost with you. At times more than one session is necessary to achieve a balanced mouth.

During a typical first treatment the technician might take care of rotten or broken teeth, remove spikes, level molar surfaces by filing waves and points, shorten overlong canines, trim incisors to a length that coordinates with the molars, and restore proper chewing angles of molars and incisors. Depending on the horse's "job" and the bit he usually wears, the technician may slightly alter the front surface of the first premolars to create a "bit seat." Without this improvement, when the bit is pulled against the teeth it can crush gum tissue, causing inflammation and pain.

Dental technicians can also identify factors that may create problems for a specific horse: conformation, demands of a particular sport, age, nutrition, and past accidents, to name a few.

Tour of the mouth

To understand some mouth basics and why most domestic horses are in need of intervention, let's start with a basic dental tour. There may be up to 44 teeth in the adult horse's mouth: 12 incisors, four canines, four "wolf" teeth, 12 premolars, and 12 molars. (Humans, in contrast, have 32 teeth.) The usual equine complement is 36 to 38 in mares and 40 to 42 in geldings and stallions. Canines ("bridle teeth") usually appear only in males; wolf teeth are nonfunctional premolars that appear in about 50 to 70 percent of all horses.

In the healthy horse, permanent incisors and molars gradually erupt or extrude as the grinding surfaces wear away. The extra length is stored in deep sockets, like rockets in underground silos.

Grass grinders

The construction and design of an animal's teeth depends on its natural diet. In the horse's case, this diet has consisted mostly of grass for thousands of years.

While green grass appears to be pliable, grass stems are actually quite abrasive due to their silicate content. This class of minerals includes quartz and semiprecious stones. This means the horse's teeth were designed to withstand years of "rock crushing" as they grind the stems into a digestible mass.

To accomplish this daunting task, the premolars and molars (also known as cheek teeth) are made up of alternating layers of cementum, enamel, and dentine. These materials are of varying hardness, so the teeth wear unevenly and are always washboard-rough, a perfect grinding surface.

In the rear of the mouth, the grinding teeth – three molars and three premolars – together form a six-tooth "table" which fits against the "table" of the set above or below. The lower molars are narrower than the uppers, and sit about a half-tooth-width inside the edges of the uppers.

When the horse chews, the food is ground between these tables as the lower jaw moves down, out to the side, up and in again. Normal chewing consists of a circular motion several times in one direction, then a shift to chewing several times in the other direction forming a symmetrical figure eight pattern overall.

By far the biggest contributor to malfunction of the horse's mouth is the modern horse's diet. In order to keep functioning properly, the length of the horse's front teeth (incisors) must be balanced with that of the back teeth or cheek teeth (molars). In their natural environment, horses wear down their incisors as they grip and bite bundles of grass, and wear down their molars when they chew it.

When we feed horses food like hay, grain, and pelleted products that have already been cut from the ground, the incisors do not get the opportunity to work and do not undergo normal abrasion. They become much longer than the molars, preventing the molars from making contact and chewing properly.

In the cases where the incisors become too long (this includes virtually 100 percent of horses that eat processed foods), the mouth becomes out of balance and sharp "points" form on the edges of the molars. Points also form as a normal part of molar crown wear.

Points can interfere with chewing, trap food particles, and irritate the inside of the mouth. Points can be filed away (the procedure commonly known as "floating"), which temporarily alleviates some discomfort.

If your practitioner reports your horse has very little problem with point formation, however, it doesn't necessarily mean that his mouth is performing properly. Dana, the gelding with back "spikes" growing up into his jaw, could only move his up and down. Because Dana only formed minor points and required only occasional floating, the practitioners incorrectly assumed all was well.

A variety of other factors can cause uneven wear of the teeth and resulting poor function of the mouth. These include unmatched, rotten or missing teeth, injury, abnormal eruption and uneven chewing. Poor mouth conformation, such as the popular "teacup" muzzles of some breeds (Arabs, Morgans, and Pasos in particular), may prevent normal wear. Miniature horses are particularly at risk.

Evaluate your horse's mouth

With such large, powerful teeth to contend with, it is dangerous for horse owners to reach inside the horse's mouth to check for dental problems. By following the tips listed below, however, a horse owner can safely look for signs of dental problems from the outside.

A dental exam is in order if you observe any of the following eccentric eating patterns: tilting the head sideways to chew, eating hay before grain, bolting grain, dribbling food, choking, or dunking food in water. The horse which has difficulty holding normal weight; endures an unexplained weight loss or frequent colic episodes; has a change in eating or drinking habits; or has a need for specialty processed foods also needs a thorough exam.

Difficult behavior may relate to dental problems. This would include hypersensitivity to or evasion of the bit (boring on it or going behind it), cribbing, tooth grinding, rooting, head tossing, refusing to open the mouth for the bit, stiffness, rearing, resistance to "going on the bit," difficulty flexing the pool, tilting the head sideways when asked to turn, collect or perform lateral movements. A pained or worried expression, or a "bad attitude" can be caused by dental pain. A horse with persistent neck tension, spinal misalignments, or hock pain may also have severe dental problems.

Observe the symmetry of the horse's face and head. The ears, eyes, and nose of the horse should be level with each other. The nasal bone should be centered in the middle of the horse's head. A lack of alignment can contribute to dental problems.

Lumps under the jaw may indicate the horse is changing from deciduous (baby) teeth to permanent ones. During this period, he may require professional assistance to insure the baby teeth are shedding appropriately.

Now examine the bite from the side. The incisors should not be overshot or undershot. Check the canines for length and position. They should not be set so far back that they interfere with the bit or be so long that they touch the guns on the opposite jaw.

Place your fist sideways between the jaws just ahead of the throat. If your hand doesn't fit (even with ponies), it indicates unusually narrow jaw conformation and potential dental problems.

Smell the horse's breath. Bad breath in the horse means rotten teeth, rotting vegetation stuck between the teeth, or an infection in the mouth. Drooling is not normal.

Observe the horse while he is eating. One-sided or up-down movement is not normal. Some food may fall from a healthy horse's mouth while it is chewing, but excessive loss indicates a problem.

Lift the lips and examine the bit from the front. Are the six incisors even across, or longer on one side than the other?

A healthy mouth

Every effort should be made to arrange annual checkups with a qualified dentist from the age of one year on. Beyond the professional care, however, there are a number of things you can do to ensure the health of your horse's mouth and jaw.

When your hands are on the reins, they are also in the horse's mouth. The bit is not a brake! "Driving the horse onto the bit" or jerking through turns or stops causes painful gums, resistance, and pulling.

One veterinary dentist refers to modern American breeding practices as "survival of the Cutest." When making decisions about breeding stock, owners should select horses for good dental conformation just like any other trait.

The quality and type of food your horse eats are two other contributors to overall mouth health. Be sure to make sure your horse's hay is clear of any weds and dirt. Foxtails, barley bears, and speargrass (to name a few) can cause mouth sores and ulcers.

Wild horses graze as much as 12 or more hours daily. When horses cannot graze, their teeth wear unevenly. The more grazing time a horse gets, the better.

Barbara Chasteen's illustrations have been featured in TWHJ since the first issues. Chasteen furthers her knowledge of equine anatomy daily, offering equine massage, acupressure, and therapeutic in-hand and warm-up techniques through her business, The Balanced Horse, in Sonoma County, California. She is also a dedicated dressage and trail rider.