Your Full-Service Veterinary Clinic

Pre-Surgical Information

Spaying or neutering your pet is a big step! There is a lot to consider when we are planning your pet’s surgery. Here is some information to help you make wise decisions. Click here . . .

Special Library

Our Special Library is a collection of informative articles on a variety of health topics. Click here . . .

Discharge Instructions

Click here for information on how to care for your pet at home. Click here . . .

Equine
Dentistry

How long can a horse live? Until his teeth wear out. That's how important dental care can be for you horse.

Dr. Nield (that's me) has been practicing Advanced Equine Dentistry since 1997. I was one of the first veterinarians in the state to use power instruments. I have had extensive training from such well-known veterinarian dentists as Jack Easley, DVM, and Scott Greene, DVM, and years of experience since. My training as both a veterinarian and as an equine dentist allow me to see the whole picture. Not every thin horse has bad teeth, and not every deviation form "textbook normal" is a bad thing. My years of experience help me know what needs "fixing," and what is normal. I tell you this not to blow my own horn, but because there are lots of opinions out there as to what constitutes "good dentistry," and I want you to know where I am coming from.

Floating

It all starts off with the Float Job. To be honest, there is not really a good simple definition of what it really means to "float" a horses teeth. To really understand what it means to float a horse's teeth, we have to start at the very beginning, which is the horse's mouth itself. Horses have teeth, and people have teeth, but that's pretty much as far as the similarity goes. Equine teeth are radically different from human teeth, both in form and in function. Equine teeth are what the scientists call hypsodont teeth. This sounds like something a dinosaur might have, but all it really means is that the teeth grow throughout the horse's life.

Well, they don't really grow throughout the horse's life. They start out as long as they ever will be (about three inches long), and they never get any longer. It's just that all the length is hidden up in the horse's jaw. Horse teeth work just like the lead in a mechanical pencil. Only the tip sticks out to chew/rub on the paper. As the tooth wears down from chewing, the tooth erupts (moves down) a little more. The images show a horse skull with the jaws burred out to show the tooth roots. To the left is a young 7-year-old horse. The lead here is new and long. To the right is an old 20-something horse. No need to burr this skull. The teeth

are ready to fall out. Horse teeth wear about 2 or 3 millimeters every year. Coincidentally (or not so much so), the teeth also erupt about 2.5 to 3 millimeters a year. So the tooth, just like the lead in the mechanical pencil, gets shorter and shorter until all that is left is a little stub that finally gets wobbly and then falls out.

You can do the math. Three inches of total tooth minus 1 inch (which is the length of old teeth when they finally fall out) equals 2 inches of tooth to wear away, which is 50 millimeters. Divide that by the 2 to 3 millimeters the teeth wear each year and you get 17 to 25 years of tooth lifespan. Add five years which is the age at when all the molars are in wear, and you get 22 to 30 years, which turns out to be about as long as most horses live. Isn't science cool?

Horses do not chew "up and down." They chew side to side, just like a cow. Cows are just more obvious about the side-to-side nature of their chewing stroke. When a horse's molars come into contact, the tooth in the lower jaw comes up into contact with the wider tooth in the upper jaw, then slides sideways across the wider upper tooth in an inside-to-outside direction, then drops down to end the grinding action.

Here the teeth are coming into contact Here they are grinding sideways Here they are separating.

A fundamental principle here is that a lot of the time, the lower tooth never makes cont

act with the outside edge of the upper tooth. With soft diets, the horse does not have to make a very long chew stroke to grind up the feed. Try this yourself. Go out to eat at a bad restaurant. Order a tough steak and a baked potato. Chew them both, one at a time, and see how your teeth grind together. When you chew the potato, your teeth do not grind together much. The chew stroke is mostly up and down. But when you chew the tough steak, you will find yourself making a big broad grinding motion that is largely side-to-side. You subconsciously adjust your chewing stroke to match the coarseness of what you are chewing.

When horses eat soft diets, they do the same thing. A softer diet results in them chewing with a small grinding stroke, and the bottom tooth never makes much contact with the outside edge of the upper tooth. As a result, a lot of wear happens on the middle and inside edge of the tooth but little wear happens on the outside edge, and a sharp point is the result.

So what counts as a soft diet for a horse? Basically, anything but grass. In the wild, horses eat some very coarse forages most of the year. In the spring, the grass is young and soft, but during the late summer, fall, and winter, the grass is quite tough. This means that horses fed grass hay, which is harvested in the young soft stage, are eating a softer diet than nature intended. Alfalfa hay is even softer, as alfalfa does not contain all the fiber and silicates that grass has. All grains count as soft, too. So basically, most of the things we feed our horses are softer than the native grasses nature intended them to eat, and promote point development.

Points do a lot of bad things. Points can traumatize the cheeks, causing pain and sometimes quidding (the intentional packing of feed in the cheeks to protect the painful soft tissues). Points also make it impossible to make a good broad chew stroke, which makes it difficult for the horse to chew it's food. Some of the things a horse does to compensate for points an lead to other wear-related abnormalities that will be discussed below. The image to the left shows some of the cuts points can cause in a live horse.

Floating is the removal of these sharp points. Done well, floating removes the sharp points, does not remove hardly any of the chewing surface of the tooth, and removes enough of the enamel fold above the point so that the float job will last a year or more. The goal is to turn a radius on the outside edge that is big enough to allow for the 2.5 to 3 millimeters of wear that is going to happen while not allowing for new points to form. This means that the "radius" actually has to be an "assymetrical radius" which leaves as much chewing surface as possible while removing enough of the enamel folds to prevent new points from forming too soon.

Beyond Floating

There can be a number of abnormal things that can happen to a horses teeth. These abnormal wear patterns all interfere with the horse's ability to chew properly. They have various causes, and they generally have interesting-sounding names that date back to the 1800's. Fixing these abnormalities is beyond "floating." The fact is, we don't have a really good name for this kind of dental treatment. Some folks call it Equilibration. Others favor Balancing. Some call it Corrective Dentistry. Others call it Advanced Equine Dentistry. Whatever it is called, it is both an art and a science, and it involves power tools. What's not to like about that?

Above and to the left is what is known as a Wave Mouth because of the wavy nature of the chewing surface. To the right is a hook, named after the hook-like beak that has formed on the first upper tooth.

Above and to the left is a Ramp, which is like a hook only bigger. To the right is what is known as Exaggerated Transverse Ridges, or ETR's. Here, the normal irregular surface of the teeth has become abnormally exaggerated. This is not an all-inclusive list. There are a number of other interesting abnormalities that can happen. One key point is that every mouth is different, both in shape and in function, and they all need to be evaluated individually.

Incisor Problems

The incisors can develop a whole other set of problems. Sometime incisor problems develop as a result of problems happening farther back in the mouth. Other times they develop because of problems happening with the incisors themselves. Sometimes they need to be fixed so the molars can work properly. Other times they are adaptive changes that actually help the molars (which may be abnormal or not) work better. It takes skill and judgement to tell the difference.

Performance Dentistry

A horse's teeth can have a major effect on their perfomance. Since we communicate with our horses largely through their mouth via the bit, problems here can mean problems in performance. Can you imagine Liberace playing with a hangnail, or Fred Astaire dancing with a bunion? In events where focus is vital, or where 1/10th of a second can mean all the difference, properly-done Bit Seats can make all the difference. Bit seats are not really meant for the bit to ride in. A properly fitted bit will not bang into the first cheek teeth. But, and this is true for both stiff and broken bits, they will press the cheeks onto the first cheek teeth. And if those first cheek teeth have sharp points and edges on them, there will be pain when that happens.

Above are two images of that first cheek tooth before bit seats. Notice the sharp points and edges.

Then two images after bit seats. The forst cheek teeth are now round and smooth like a cue ball.

This provides a smooth, pain-free surface for the cheeks.

And let's not forget wolf teeth. Wolf teeth are not the big teeth you bang the bit into when you bit up an older gelding. They are small teeth positioned just in front of the first cheek teeth. They are mentioned in the section on bit seats because they cause the same kinds of problems that sharp first cheek teeth do. They cause pain when the bit presses the cheeks on to them. They should be removed from every horse that has them before the horse starts training.

Routine Dentistry

How often do horses need dental work? Most horses should have their teeth examined every year. Horses that I personally float may or may not need additional work done every year. It is not uncommon for them to not need follow-up work for 18 months. But I still recommend an annual exam because a lot can happen in a year. Also, horses that I personally float usually don't need as much follow-up work, which means that it costs less. I find that horses that receive annual dental checkups and work rarely develop problems.

Every 2-year-old should have dental work before going into training. Emphasis on before. The goal is to make training as stress-free as possible, and that may not happen if they have sharp points and wolf teeth interfering. Yes, your 2-year-old will soon shed his first caps and will need another bit seat soon, but when they are just starting out in the bit, a comfortable bit seat can be very valuable.

The older the horse is, them more likely he is to need corrective dentistry. Our goal with the older horses is to optimize the way he chews, not to make his teeth conform to a pre-determined standard of perfect. We try to minimize the amount of tooth we remove, because they only have so much tooth to work with, and it has to last.

Equine Dentistry is a big, big field, with way too many details to cover on one web page. We look forward to seeing you and your horses, and helping them and you to get the most out of their visit.