For the average horse with normal tooth development and regular oral exams, dental care is generally straightforward. Sharp enamel points are reduced, the mechanics of the mouth are evaluated and maintained, and considerations are made for performance horses (e.g. bit seats and wolf tooth extractions). For these horses, some degree of ulceration of the cheeks and tongue are the most common findings, and the oral tissues heal quickly once the offending enamel points are removed.
The incisors (the teeth in the front of the mouth) are the most frequently affected, with fractures of the cheekteeth (molars and premolars) being less common. While trauma from kicks and other impacts are often implicated, most often the cause is undetermined and the fracture is termed idiopathic.
Small chips or slab fractures above the gumline and not involving the pulp horns of the tooth may cause no obvious clinical signs. However, fractures through the body of the tooth and exposing the vessels and nerves within will often result in instability, packing of feed materials, displacement, and infection. These horses will present with quidding (dropping feed), posturing of the head and neck while eating, foul odors, and/or bitting and performance issues. Most often these teeth require surgical extraction.
Oral infections can be found to varying degrees in horses’ mouths. Periodontal disease often occurs where feed materials or tartar accumulate, and if left untreated may progress to gum recession and infection reaching the apex, or root, of the affected teeth.
Other culprits include the previously mentioned fractures, as well as dental caries that result from the acidic byproducts of oral bacteria. As infection progresses, the tooth may become painful and loose, and weakening of the surrounding bone can predispose these horses to fractures of the jaw.
Infections that involve the maxillary (upper) cheekteeth may ascend into the sinuses, resulting in nasal discharge and requiring aggressive flushing to treat effectively. While mild periodontal disease can usually be treated locally, more severely affected teeth are often extracted following radiographic evaluation of the deeper structures.
Malocclusions are defined as abnormal contact of opposing upper and lower teeth. Because of the continual eruption of the equine tooth, unopposed teeth or portions of teeth will develop long projections that can cause painful ulceration of soft tissues. Additionally, these projections can limit the normal range of motion of the mandible.
For example, a horse with an overjet (parrot mouth) may develop large hooks on the rostral (front) edge of the first upper cheekteeth and corresponding ramps on the last lower molars. These overgrowths can inhibit the normal forward slide of the mandible when the horse lowers his head to graze or is asked to flex at the poll under tack, and their severity can worsen with time.
Early detection and routine maintenance are key to managing malocclusions; therefore foals should be examined at birth and every six months thereafter until all of the permanent teeth are in place around age five.
Dental Concerns for Senior Horses
Geriatric horses commonly develop dental problems as well. Because the root end of the tooth is narrower than the crown, the teeth appear to shrink as a horse ages, and spaces termed diastemata develop between them. These small spaces are a perfect place for feed material to lodge, often leading to periodontal disease and infection.
As a horse approaches 30 years of age, his cheek teeth lose much of the ridge-and-groove architecture that allow him to grind grains and forage. These teeth are often referred to as expired, or the horse may be described as having smooth mouth. Special dietary considerations must be made for horses that are unable to adequately process feed, in order to prevent choke while still providing adequate caloric intake.
It’s important to note also that oral anomalies are not limited to the teeth. Trauma to the tongue, lips, palate, and bars of the mouth can be caused by inappropriate bits. Inflammatory conditions of the gums and cheeks may be seen in horses grazing on certain weeds. Oral tumors of varying origins may affect any number of oral structures.
By affecting and restricting the mechanics of the mouth, dental problems have an uncanny ability to compound themselves over time. While many of these dental anomalies aren’t preventable by even the most astute owner, the key to managing them is early detection. A thorough oral examination at least once annually (more frequently in young horses) allows the veterinarian to identify and treat pathologies before they become more even painful and costly.