The horse is an obligate herbivore, which just means that the diet of the horse is strictly plant based. In order to digest the amounts and types of roughage that a horse must consume on a daily basis, they have to do a whole lot of chewing. This constant chewing wears away the teeth on a constant basis. To compensate for this wear, the horse has a type of tooth that has both soft and hard parts, and the teeth erupt continually, but very slowly, at a rate of about 2-3mm a year. The upper jaw of the horse is slightly wider than the lower jaw, and as the teeth erupt and are worn away by chewing, the edges that do not meet together continue to grow without being worn down and they get sharp. These sharp points cause pain and discomfort by eroding the cheeks and tongue, they can inhibit the chewing motion of the jaw causing poor digestion leading to weight loss, poor performance, and increasing the risk of choke and colic. These sharp points can inhibit performance by causing pain, and inhibition of the movement of the jaw that allows a horse to break at the poll and collect. The periodic removal of these sharp points is necessary to minimize oral pain and will prolong the length of life as well as improve the quality of life of your horse.
Cheek Teeth in Situ
This photo shows how the cheek teeth lie within the upper and lower jaw. As the horse ages these teeth constantly push out and are worn down by chewing. By the time the horse is in his late 20's, there is very little reserve tooth left and hence the teeth begin to fall out. This obviously makes chewing more difficult in the aged horse and dietary changes will need to be made in order to compensate.
The Upper Arcade
This is a nice photo of a side view of a normal equine mouth. The incisors, canine teeth, premolars and molars are clearly labeled. Canine teeth are commonly mistaken for wolf teeth. The wolf tooth is a very small tooth that lies directly in front of the first premolar. Horses can have from 1 wolf tooth to 4 wolf teeth(upper and lower). Two upper wolf teeth are the most common and they can be present in both males and females. Canine teeth are also known as bridle teeth and generally come in at about 5 years old. Canine teeth are much more common in males than females, but occasionally you will see a mare with canines.
The Lower Arcade
In this photo we see the teeth of the lower arcade. In the normal horse they correspond in number, placement and size with the upper teeth. Abnormalities occur when there is a mal-allignment between the upper and lower teeth. These mal-alignments cause problems much more severe than just growing sharp points, and those problems can be difficult to correct and maintain.
The sharp enamel points that result from the constant eruption of tooth combined with the chewing action. The areas of the teeth that do not meet together do not get ground away and therefore become long sharp points. The outside or buccal aspect of the upper teeth become sharp and the inside or lingual aspect of the lower teeth become sharp.
Wolf teeth are small teeth that sit directly in front of the first large cheek tooth. They are a non-functional tooth that can vary in size from quite small to very large. Horses can have up to 4 wolf teeth, although some horses never get them. The wolf teeth are generally extracted at around 2 years of age to eliminate pain caused by the bit bumping into them. In this photo two good sized wolf teeth are circled in red. The next photo shows the same horse without the red circles and the final photo is of the wolf teeth after removal.
This is a photo of several large ulcers that have been worn into the sensitive cheek tissue by sharp enamel points. These ulcers are painful, cause difficulty chewing, difficulty performing in the bridle and can become infected. Once the sharp points have been reduced the ulcers heal very quikly.
This photo shows a large ulcer on the side of the tongue caused by a sharp point on a lower tooth. Ulcers such as this one cause pain and can lead to tongue lolling or rolling. As with cheek ulcers, tongue ulcers heal rapidly once the offending point has been removed.