Putting a file in a horse's mouth may not be the most intuitive part of horsemanship, but it can be an important part.

"Floating" a horse's teeth is so named after a similar practice in masonry, when a file is used to level bricks. The idea of floating teeth is to take care of problems that may interfere with your horse's health. Horses' teeth grow constantly throughout the lives, around 2-3 millimeters per year, to make up for the grinding-down that happens as they graze.

Most of the horse's tooth is deep, below the gums, and keeps erupting into the mouth, says Bruce Connally, DVM, who has an equine practice in Berthoud, Colorado. He taught dentistry to veterinary students at Colorado State University and then practiced for a number of years in Wyoming. "The visible teeth are 3 or 4 inches long when the horse is young, but gradually wear down and get shorter and may wear out (and push on out) sometime in the horse's 20s or 30s, depending on what he has been eating. On pasture or grass hay, teeth wear more evenly than when horses are eating alfalfa hay or cubes," he says.

Dental care for young horses

Foals have baby, or deciduous, teeth that erupt from the gums at different times and are later shed and replaced by adult, permanent teeth, says Rachel Shutter, DVM, Dakota Hills Veterinary Clinic in Rapid City, South Dakota, who sees a lot of equine patients for dental care.

Shutter recommends a dental check at 2 to 3 years old because a lot of changes happen in a horse's mouth at 2 to 2.5 years old. "At that time we can start recognizing any pathologies that we might be able to fix. It's a lot easier to prevent some of these problems than to try to deal with them later. If I don't see the horse for a dental check until 18 years down the road, at that point there's not much I can do to fix a problem that started many years earlier," she says.

The training that happens at 2 to 3 years old also puts more demands on their mouth and dental problems can turn into training problems.

If the young horse is fighting the bit, or not wanting to turn a certain direction, or showing discomfort in a bridle, it is important to think about what might be happening in the mouth. "There are many changes that could be a cause of discomfort. There may be a cap (baby tooth) that is still retained that needs to come off, for instance," says Shutter.

"People used to rip caps off as soon as they found them," said Connally. "But now we realize that if we pull the cap off too soon this can damage the enamel on the incoming permanent tooth. Today we don't pull caps as aggressively as in the past, but there are some that do make the horse uncomfortable and those need to come off," he says.

The horse's baby teeth, which are softer and often wear more quickly and unevenly than permanent teeth, sometimes develop sharp areas that can cause discomfort in the soft tissue around them. Usually baby teeth are replaced by permanent teeth by age 5, said Connally.

Tooth bumps (enlargements at the middle area of the bottom jaw) are another thing people worry about, thinking the lumps are infections or some other problem. These enlargements are due to impaction of the bottom molars as those permanent teeth are coming in, when the horse is about 3. "Most of the time these resolve; those bumps go away by the time the horse is 4 or 5," Connally says.

Wolf teeth can be another issue in a young horse, but most of the time wolf teeth are too far back to cause trouble. They can be a problem when they are pointed in toward the tongue or out toward the cheeks, making the horse uncomfortable. "These are just the first deciduous premolars, and smaller than the other teeth. Wolf teeth get blamed for a lot of problems with a bit, though most bit problems are due to the rider's hands rather than the bit itself. It is worth checking them. Most horses shed wolf teeth by the time they are 3, but some don't, and if they cause a problem, they need to be removed," Connally says.

Potential problems in horses' teeth

A horse chews by moving the lower jaw in a circular pattern, almost like a figure eight, says Shutter. The bottom jaw is narrower than the top, so the teeth sometimes develop points on the outside edge of the top teeth and the inside edge of the bottom teeth. Since the teeth are naturally slanted, these points can dig into the cheek or tongue and cause sores.

The most common pathologies, besides points on the teeth, are hooks or ramps on the first or last set of cheek teeth–on the first set of premolars and on the back molars. The average horse's jaws are slightly mismatched in length, so the front part of the tooth or the back part of the tooth continues to grow because it is not being worn by the opposing tooth. It starts to hook over the top or bottom tooth. When these hooks get very long, they prevent proper chewing motion, Shutter says.

When a horse gets old, there might be no more tooth below the gum to keep erupting. "It may happen at age 20, or 30; every horse ages at a different rate. Depending on how the horse ages, and what it was eating during its lifetime, teeth may start to fall out. The first one to come out is usually the 9, which is the oldest permanent tooth in the horse—that came in as a yearling," she says. This tooth is in the middle of the check teeth.

When a horse loses a tooth the opposite side doesn't have anything to grind against, and the teeth on either side of the gap start moving toward each other. Feed can get packed into those spaces, which can cause a gum infection and potential for abscess.

"A tooth abscess may result in a nasty discharge from one nostril, break out through the skin below the eye to drain out. These situations need veterinary attention," Connally says.

For mares especially, the canine teeth (bridle teeth, just behind the incisors) can sometimes cause trouble. Many mares don't have canine teeth, but some do, and in some mares those teeth are small and just under the gum surface and don't fully erupt and can cause pain. "In geldings or stallions those teeth usually come in," Connally said, "but in the mares that have canine teeth just sitting under the surface there may be some tenderness. I've had to cut the gingiva off the top of some of those just so those bumps aren't causing discomfort."

Other problems that can occur include a wave mouth, which happens when the teeth are different levels, often because the teeth erupt at different times, says Shutter.

Frequency of dental care

"I see a lot of horses that had no dental checkups until their late teens or older. Many owners don't start to think about teeth until the horse starts losing weight (unable to chew feed properly, or not eating enough because of a painful mouth) or dropping feed out of the mouth. I urge people to get their horses checked at least once a year, at an earlier date, so we can prevent the weight loss and painful eating, rather than just trying to fix something that's already going downhill," says Shutter.

Middle-aged horses, which are past the "young horse" problems and not yet to the "old horse" problems often are fine with a check every other year, but others need to be seen every six months.

"Very few, in my experience, need to be floated every year, but we still need to check," says Connally.

Some equine dentists suggest floating teeth more than once a year. Unless there is a specific problem they are trying to address and it's a short-term situation, get a second opinion or find a new dentist. "Only in unusual circumstances would a horse need this many treatments. If they are floating horses that often, those horses will run out of teeth too soon, before they run out of years. This could shorten the horse's functional life," Connally says.

Cost and Qualifications

The cost for dental care varies around the country and from one veterinary or dental practice to another. "In my practice, a float will be $130 to $150, which includes sedation. In some regions the total cost may be double or even triple that amount," says Connally.

In the past, many people floated teeth without sedation. "You can do some things without sedating the horse, but the owner should expect that the horse will be sedated, with a speculum to hold the mouth open so the practitioner can do a thorough job. This will cost more than a dental exam/work without sedation. Depending on what we have to do inside the mouth, it will take about 30 to 50 minutes," he says.

It can sometimes be a challenge to find a reputable practitioner. "Word of mouth is still how a lot of people find equine professionals.

Connally says to be wary of equine dentists who want to float teeth more than once a year, without showing you a specific problem they are addressing or who do a brief check and a couple swipes with the float without sedating the horse.

"The equine dentists who want you to have the horse done twice a year are often the ones who don't have any other way of making a living and all they do is float teeth," he says.

Some equine dentists don't use sedation, which makes it difficult to really see what's happening in the mouth, Connally said.

Not all states require equine dentists to be licensed veterinarians, but some do. Vet schools are starting to put more emphasis on equine dental work, and there is a board certification for veterinarians in equine dentistry.

However, non-veterinarians can't legally sedate the horse, and there's also the issue of insurance, said Shutter.

"If something were to go wrong while they are working on your horse, there is no malpractice insurance and no veterinarian backing them up. Sometimes even with the sedation, we still struggle, so I don't think a person can do a very good job without using pharmaceuticals. I encourage horse owners to do some research before they decide where to take their horse, making sure that the person doing the job is comfortable doing dental work–and also making sure everything is legal," says Shutter.

However she also suggests keeping in mind that not all veterinarians are comfortable with equine dentistry. "Just like any other type of medicine, each veterinarian has his/her own comfort level in what they want to do or are good at. Some veterinarians don't like to do dental work. When you are calling around to different veterinary clinics, check to see what they prefer doing," she says.

TELLING A HORSE'S AGE – "Aging horses by examining the incisors is moderately accurate, until about age 9 or 10—by looking at when the different permanent teeth come in, and observing the wear on them. After about age 10 it becomes harder to tell the age," Connally says.

Even in young horses the wear can vary, and this can be deceptive when trying to determine age. If a horse is eating sand with his feed, the teeth wear faster and he will appear to be older.

From birth to 6 months, baby teeth come in, including the first three molars. The first molar appears at 6 to 8 days and the next at 6 to 8 months. The foal has three front teeth at 6 to 8 months, and the first three molars. The first three molars (teeth number 6, 7, and 8) shed their caps at ages 2 1/2, 3 and 3 1/2. The canine teeth (bridle teeth) come in at 4 to 4 1/2 years.

The next three molars (teeth number 9, 10 and 11) start coming in before the first three shed their caps. The number 9 tooth comes in at a year of age; the 10 appears at 2 years and the 11 at 3 years. By that time the horse has all the cheek teeth, but these are not all permanent. The baby teeth come out in the order they came in, as they are replaced by the permanent teeth erupting.

When estimating age in older horses, it depends on how the teeth have worn. At age 8 all the lower cups are full. By age 10 the cups are worn away and the mouth is smooth. At 10 Galvayne’s groove appears at the top of the corner incisor, and by age 15 has worked its way halfway down the tooth. It is all the way to the bottom by age 20, and then starts receding back up. That can be a clue to a horse's age, unless a dentist has worked on the teeth and taken some of that tooth off.