Dental Hygiene

Horse owners often ask me, "Doc, could you float my horse's teeth?" Horses do need their teeth floated on a regular schedule; the frequency might change with the horse's age. Something that doesn't change with age is the need for a thorough oral and dental examination.

Floating means to smooth, and it's a term borrowed from the carpentry and masonry trades that refers to smoothing plaster or concrete after it is applied or poured. But, just as you expect an examination of your own teeth before any therapy is started, expect the same thing for your horse. The examination can reveal many abnormalities, or it might even show your horse does not need treatment at that time.

What is unusual about dental problems is that there is a high occurrence of dental and oral disease with few clinical signs. In other words, a disease might be well advanced before your horse shows any problems. Gingivitis, periodontal disease, chipped or fractured teeth, dental caries (cavities), and malocclusions all can be detected with a regular oral exam. The earlier these problems are diagnosed, the simpler and more effective the treatment will be.

Several items are essential to perform a good oral examination. The list includes a full mouth speculum, a powerful light, dental picks, a specialized mirror, a dose syringe or spray unit to rinse the mouth, sedatives, and something to support the horse's head if needed during the examination. A quiet horse might not need sedation to complete an examination, but most horses require some degree of sedation to allow the veterinarian to perform a complete examination that's safe for the horse, the owner, and the examiner.

Why Float?

There are two main reasons horses need their teeth floated. First, the two rows of upper cheek teeth are set 30% wider apart than the lower two rows of cheek teeth. This requires the horse to chew side- to-side in order to make complete contact, or occlusion, creating a 15-degree angle on the chewing surfaces. Second, equine teeth continue to erupt from the dental alveoli (tooth sockets) and are slowly worn away over the horse's lifespan. Cheek teeth have enough reserve crown to last an average of 20 to 25 years with normal wear.

Lateral chewing--plus the constant wearing of the occlusal surface--causes sharp edges and points on the outer edge of the upper cheek teeth and inner edge of the lower cheek teeth.

These sharp points irritate the cheeks and tongue. Eventually ulcers develop, usually in the cheek beside the last three upper cheek teeth. The bridle and bit press the part of the cheek that's behind the corner of the mouth into these sharp points on the first and second upper cheek teeth, causing pain and discomfort. Ulcers can develop there because of this pressure.

Oral pain is a common cause of performance problems, such as the horse opening his mouth, excessive tongue motion, flipping the nose upward, uneven tension on the reins, and lack of suppleness in turns and transitions.

How Often to Float?

A dental examination is recommended annually for most horses; those with ongoing problems should be seen more often. Frequency of floating also can vary with age.

Young horses (six months to two years of age) benefit from examination every six months. At that age, little shaping is done to the deciduous or baby teeth. Deciduous and newly erupted permanent teeth have less dense tooth material and are easily smoothed. Points that form in foals prior to weaning can be very sharp, but only light floating is needed, and motorized floats are generally not needed.

Foals should be examined for proper alignment of the incisors so abnormalities can be identified and corrective treatment can be started as soon as possible. Wolf teeth are more easily removed soon after eruption at around five to seven months of age.

Horses ages two to five years old have lots of changes occurring in their mouths. During that period, the horse is shedding 12 premolar and 12 incisor deciduous teeth, and he's erupting four canines, 12 permanent premolars, and 12 molars.

Two- to 5-year-old horses should be examined two or three times per year and floated as needed; sometimes that means just floating the teeth that have begun wearing and have points since the last exam. Retained caps can be removed and periodontal disease that sometimes occurs with cap exfoliation is treated. Deviated or improperly erupting teeth can be identified. These can be a possible source of periodontal disease if food becomes trapped and corrective action is not taken. These exams can also allow malocclusions from unequal tooth eruption to be detected and corrected soon after they appear.

Mature horses (ages five to 18) should be examined every six to 12 months and floated as needed. Performance horses are usually floated every six months.

Geriatric horses, generally those horses over 18 years of age, should be examined every six to 12 months and floated as needed. Horses in their early 20s might need floating every 12 to 18 months, and horses in their late 20s might only require floating every 12 to 24 months. Geriatric horses have a higher incidence of periodontal disease and other age-related changes.

The total surface area of geriatric cheek teeth is reduced because the tooth is smaller in circumference toward the root. Geriatric teeth have less enamel infolding (areas where tooth enamel has folded inward to create an appearance of pits and fissures--infolding makes teeth rougher and better at grinding forage). These changes mean the geriatric horse has lost some capacity to grind hay into small pieces, and he will have to chew longer than a younger horse to reduce hay to a small particle size.

Periodontal Disease

Periodontal disease is an inflammatory disease resulting in damage to tissues and structures surrounding the tooth. Gingivitis (gum inflammation) is usually the first sign of early periodontitis and is often seen around the canine teeth and the incisors. Severe periodontal disease can occur when food becomes trapped in pockets between the gingiva and the tooth or between teeth if the teeth fail to maintain contact. If a space develops between teeth (called a diastema), food becomes trapped and accompanying bacteria discharge byproducts that destroy the tissue around the tooth.

A thorough oral examination is necessary to detect periodontal disease because there might be no outward sign until the disease is advanced. It has been proven that the bacteria in periodontal pockets can spread to and infect other organs in animals and people.

Dental Caries

Caries usually occur in the upper cheek teeth. The upper cheek teeth have two small, funnel-shaped openings or infundibulums, which were the channels for blood vessels into the tooth prior to eruption. These openings might become large enough to hold food, which can ferment and erode the cementum and enamel.

Since the tooth is always being worn down, the cavity might not become large enough to justify restoration, but the progress of the cavity should be checked with each examination to determine if restoration is needed.

Dental Malocclusions

An oral examination includes evaluation of occlusion of the cheek teeth and the incisors. Malocclusions are identified and either completely or partially corrected, depending on the size of the abnormality. Some common malocclusions are hooks, ramps, wave or step mouths, and exaggerated height to the ridges on the occlusal surface. Malocclusions detected early can be corrected in one session, while long-standing malocclusions with overgrowths greater than 5-6 millimeters might need more than one session for correction. Staged reductions in overgrowths reduce the chances of exposing or damaging sensitive pulp (the soft inner structure which consists of nerve and blood vessels).

The function of incisors is to bite off grass and collect hay. The upper and lower incisors should meet on a level plane (the soft inner structure, which consists of nerve and blood vessels). Abnormal incisor wear results from missing or damaged incisors, abnormal eruption, or abnormal chewing patterns. These abnormalities might need special correction performed over time. There are limits on how much incisors should be reduced to minimize the chance of pulp damage.

Malocclusions are the most commonly seen dental abnormality. When they are diagnosed early and regular correction is applied, normal occlusion and function can be maintained usually for the life of the affected teeth. Severe malocclusions detected in geriatric horses suffering from long-term neglect might be impossible to correct, and treatment is directed at making the horse comfortable. Diet changes --such as complete pelleted rations or chopped hay--might be necessary.

Take-Home Message

If a thorough dental examination reveals dental abnormalities, such as fractured teeth, periodontal disease, caries, or oral/nasal discharge, the examiner can take radiographs to further diagnose the extent of the disease and to better formulate a treatment plan.

Remember, getting the examination is more important than just getting the teeth floated.

About the Author

B.A. Rucker, DVM

B.A. Rucker, DVM, is a 1975 graduate of the University of Georgia Veterinary School and has a private practice in Virginia limited to equine dentistry. You can contact him via e-mail at

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