Tallgrass Animal Acupressure Institiute

What Every Rider Needs To Know
about Equine Dentistry
by Nancy Camp
with thanks to Casey Jones, Equine Dentist,
and Heather Mack, DMV

Discomfort in a horse's mouth is not always bit related. An unbalanced mouth is uncomfortable and/or painful. It also affects the horse's ability to move its head. Requiring a horse with dental imbalances to turn his head, raise it or lower it, while haltering, leading, tying, or riding, will increase his discomfort. An amazingly high number of chiropractic and behavioral problems are related to dental imbalances. Consider such problems as head tossing, stiffness in the neck, shoulders and/or back, resistance to raising or lowering the head, pulling back while tied, and difficulty turning. Any of these behaviors may be manifested by dental imbalances. The most commonly acknowledged reason for routine dental maintenance is to promote good mastication which in turn aids in digestion and helps prevent colic. But what is the nature of routine dental maintenance? It is more than having your vet file or grind points off the front molars once or twice a year. The following is what you as a rider or horse owner need to understand about routine dental maintenance. It is your responsibility to know this information and supervise what is done in your horse's mouth. First of all, what constitutes a balanced mouth? A balanced mouth has good occlusion; the teeth meet each other evenly without high spots that cause pressure or low spots between the surfaces of upper and lower teeth. Good occlusion allows for lateral excursion. Simply put, the lower jaw swings freely from side to side.

In order to understand the importance of these two criteria for balance in the horse's mouth, let's consider how a horse eats. (figure 1.) He begins by taking in food; if he is grazing his incisors do this job. He may use his lips when taking in hay. The food is directed to one side where the molars start to grind it and turn it, forming a cigar-shaped wad that travels back along the grinding surfaces of the molars to the rear of the mouth where it can be swallowed. In its journey, this wad of food will be shifted, being chewed first on one side of the mouth and then on the other. The result of this chewing process is that the horse will swing his jaw in a figure eight motion. For all of this to work the grinding tables must have a slight angle (12 - 15 degrees, depending on the breed) and a textured surface. The textured surface has enamel ridges created by varying degrees of hardness in the make-up of the teeth. It is important to note here that smooth grinding tables slide rather than grind and turn the food. Knowing this, we might question the appropriateness of using power floats. Can the angle of the grinding tables and their textured integrity be preserved with these unwieldy tools? So what happens when dental imbalances enter into the picture? Remember that the teeth are intended to wear as they continually erupt. An unbalanced mouth promotes uneven wear that perpetuates the imbalance. A horse that only uses one side of his mouth will not only wear his teeth unevenly, he will develop the muscles around his skull unevenly as well. Much can be ascertained about the nature of a horse's dental health by observing the musculature of his head. The unnatural conditions in which we keep horses contribute to dental issues. One of the most notable issues is lack of wear on the incisors. When the incisors get too long, the grinding surfaces of the molars are held too far apart to meet and function normally. (figure 3.) The horse will pack abnormally large amounts of food into the resulting gap and grinding will be ineffective. Long incisors also create pressure in the front of the mouth and pry open the TMJ (Temporal Mandible Joint). This situation causes the TMJ to be painful (He doesn't like his head touched. I have to take his bridle apart to put it on. He pulls back. I can't get near his ears. He goes ballistic when I tighten his noseband... to mention a few.) Long term, this condition can result in permanent damage to the TMJ. Other incisor imbalances (figure 4) restrict lateral excursion and cause the horse to chew up and down. This chewing pattern results in uneven wear of the molars and compromises the grinding surfaces. This creates sharp points on the molars that cut the insides of the tongue and/or cheeks and frequently result in a chronic infection along the inside of the cheeks. (He's even worse in a hackamore. He doesn't like his face groomed. He tosses his head no matter what bit I use... etc.) (figure 5) Horses with sharp points will take in extra food matter and pack their cheeks in an effort to protect them from the points. A wedge mouth, one in which the incisors are long on one side and short on the other, also prevents normal lateral excursion. 677 Should your practitioner recommend bite work to straighten out incisor imbalance, discuss their intentions and make sure that the overall balance of the mouth is being addressed. A good dentist will be aware that over reduction of the incisors will create too much pressure on one or more of the molars and can lead to further problems in the form of cracked teeth or abscesses.

When a horse turns its head or moves it up and down his teeth need to be able to slide side-to-side or front to back. Dental imbalances that prevent these actions create pain and discomfort and can result in behavioral manifestations from head tossing to rearing or running backwards. Hooks on the upper front molars will pull the skull forward of its normal placement and cause a great deal of tension. Hooks in the back can cause a horse to favor a high or excessively low head carriage. (figure 6) No matter what problems come up with a horse, add check teeth to the list of possible solutions no matter how irrelevant the connection between behavior and dentistry may seem.

The information in this article reveals only the tip of the iceberg. Bringing a horse's mouth into proper balance is an art. It requires skill, knowledge and, often, a considerable amount of time. The condition of the teeth in the mouth of any horse that you ride is your business. Your safety and perhaps even your life depend on it. So, take responsibility and learn enough to feel comfortable discerning whether or not the person you have chosen to care for your horse's teeth has the knowledge and skill necessary to do the best job possible for your horse.