Level One Equine Anatomy and Health Considerations Handout

Handout - Fast Facts for Equine Teeth

• The buccal side of the mouth is closet to cheeks

• The lingual side of the mouth is closest to the tongue

• Deciduous teeth- aka baby teeth, these are teeth found in young animals that will eventually fall out and be replaced by permanent teeth

• Permanent teeth- the second set of teeth formed in mammals

• There are four different type of teeth:

1. Incisors-found in the front of the mouth, used primarily for cutting food (ie grazing) or defense

2. Canine- these teeth are spade shaped and found directly behind the incisors, the deciduous canine teeth do not often erupt but may palpable under the soft tissue. These teeth are found in less than 1/3 of mares and may be blind, un- erupted or barely erupted. In the male these teeth are specialized for fighting. Horses may have any where from 1-4 canine teeth depending on which erupt

3. Pre molar- aka cheek teeth, used to masticate food prior to swallowing. Wolf teeth are vestigial premolars. Most horses have between 1-4 wolf teeth and are more common on the upper jaw than the lower. Mares and stallions/geldings have equal chance of developing wolf teeth. The wolf teeth are often removed to prevent interference with the bit.

4. Molar- these are also known as cheek teeth, used to masticate food prior to swallowing. These teeth move vertically and horizontally, which produces sharp points (or hooks) on the edges of the teeth. Please note the grinding surface of the equine molar teeth is not flat.

• Interdental space- an area in the mouth where no teeth grow, this is where the bit is placed when horses are ridden

• Other important terms:

• Arcade- refers to a row of teeth

• Mastication-The act of chewing food

Level One Equine Anatomy and Health Considerations 1 | ©Avalon Performance Horse and Rider Support Revised 05/08/13

• Dentin- the hard dense, bony tissue beneath the enamel and surrounding the pulp chamber and root canals

• Cement- thin layer of calcified tissue covering the dentine of the root

• Pulp- collection of soft tissues including blood vessels, nerves and connective tissues

• Enamel-the hardest and most dense substance in the body

• Periodontal ligament- the fibrous connective tissue that surrounds the root of a tooth, separating it from and attaching it to the alveolar bone and serving to hold the tooth in its socket.

• Points occur on the inside of the lower molars and on the outside of the upper molars due to uneven grinding since the horse has a wider upper jaw than lower jaw.

• Hooks occur on the front edges of the second premolars or back edges of the upper corner incisors or third molars created when the tooth is not properly worn down by opposing tooth.

• At age 7 and age 11 a hook will form on the upper third incisor. This is not a pathological condition and is other factor to be used to age the horse.

• Galvayne’s Groove & Aging a Horse Galvayne’s Groove is a groove that appears on the outer surface of the upper lateral incisor teeth. It appears at about 9-10 years of age at the top of these teeth and develops down the tooth more as the horse ages. At 15 years it will have developed more than a half of the way down the upper lateral incisors. By 20 years it reaches the bottom of the lateral incisor teeth. After 20 years old the Galvayne’s groove gradually disappears from the top down and cannot be seen in a thirty year-old horse.

• When should a horse receive its first dental exam? A horse should receive its first dental exam at birth. Congenital defects such as parrot mouth or monkey jaw can be discovered at this stage and can occasionally be managed to reduce the severity. As a rule a horse should receive a dental exam every year as when a horse starts to exhibit signs of oral discomfort the condition is usually fairly severe.

• What is the structure of the horse’s mouth? Horses have a unique dental structure. Their teeth are divided into two major sections: the incisors, which are the teeth seen in the front of the horse's mouth, and the cheek teeth, made up of the premolars and molars. The molars and premolars are lined up tightly against each other, creating the appearance of one chewing surface. This alignment of teeth is called the dental arcade. The incisors are separated from the cheek teeth by a large space. Canine teeth can be found in the space between the incisors and premolars. The incisor teeth are responsible for the grasping and tearing of food, while the cheek teeth are used for grinding of feed.

• Why is it important that the incisors are aligned and balanced? The incisors of the horse also continue to erupt as the horse ages. These teeth can become loose or wear abnormally. Loose incisors are often painful and might need to be removed. Uneven incisors will inhibit the normal side-to-side chewing motion of the horse, while incisors that are too long will prevent the normal occlusion of the cheek teeth. It is important that the incisors be evaluated and treated after the cheek teeth have been examined. Small changes in the incisors will have a large effect on the cheek teeth, especially the rear molars.

• What problems do continuously erupting teeth present? This continuous eruption and wearing of teeth in the horse results in an increase in dental problems and diseases of the oral cavity as the horse ages. While horses rarely have problems with tooth decay or gum disease, their continuously erupting teeth present unique problems. If a tooth is lost or worn abnormally, the opposing tooth will continue to erupt from the gum line. This will result in the tooth impacting the empty socket left by a missing tooth or the dominant tooth continuing to wear into the opposing arcade, magnifying the abnormality. Either of these conditions will result in mouth pain and abnormal chewing patterns. This abnormal chewing can result in weight loss, tooth infection or impaction colic.

• What is a dominant tooth and what causes it? Abnormal occlusion, missing teeth and abnormal chewing patterns can result in the creation of a dominant tooth. As the dominant tooth erupts, it wears down the opposing tooth. If not treated, the dominant tooth can wear the opposing tooth down to the gum line, resulting in feed packing into the gum line. This can result in infection of the tooth socket and its sinus.

Works Cited for Current Page: Manuel G. Himenes Jr., DVM. “Understanding Your Horse’s Teeth”. Dentistry. American Association of Equine Practitioners. .

• How Veterinarians Identify Teeth: Below is the Triadan System. This system is the most common system used by veterinarians, for all species, to discuss dentition. Remember, if a tooth is missing, i.e. the canine tooth in a female horse, you skip the number and continue on to the next tooth. For example the right upper 2 st premolar will always been known as 106 even if the right upper wolf tooth (also known as the 1st premolar and 105) is not present

• The teeth that wear out first in the equine mouth are 109 and 209 because they are the oldest teeth in the mouth. Eric Davis, DVM and Cindy McClinn, RVT. “The Basics of Equine Dentistry”. Rural Veterinary Experience Teaching Service. Web.