• Dental Abnormalities
  In horses with normal dentition, the maxilla (upper arcade of teeth) is wider than the mandible (lower arcade of teeth, or jaw). This difference in structural widths allows for more effective side-to-side grinding. To help create a level, uninterrupted grinding surface, horse’s premolars and molars are positioned in a straight line down the length of the mouth and possess smooth, flattened crowns. The crown of each tooth erupts throughout the animal’s life and is constantly worn, shaped, and sharpened by the opposing tooth in order to maintain an effective grinding surface.
  
  The problems we see in equine oral health arise from trauma, infection, neoplasia (growths) or, most commonly, abnormalities in dentition.

• Abnormal Dentition
  A malocclusion, such as a parrot mouth (overbite) or sow mouth (underbite), is structurally undesirable. If only the incisors are out of alignment, animal may be able to eat normally, but if the premolars and molars are malaligned, your horse will be more seriously affected. The portions of the dental arcade that are out of alignment will continue to grow with no opposing tooth to help grind them down. As a result, sharp hooks will form on the surfaces of the first cheek teeth and last molars. These hooks may grind the soft mucosa or gums of the maxilla or mandible, causing pain and predisposing the horse to oral infections. In addition, the hooks on the front cheek teeth may interfere with bits and thereby complicate training.
  
  During the course of normal eruption, some horses may retain a deciduous tooth or two. These caps may delay eruption or cause abnormal eruption of the permanent teeth. Sometimes, caps will remain attached to one margin of the gingiva, causing irritation when they shift. In addition, they may trap food, which will cause further agitation.
  
  When there is not enough room in a horse’s normal dental arcade to accommodate normal eruption of permanent teeth, painful impactions may result. Short-headed horses whose jaws are not long enough to accommodate all of its teeth or horses that possess retained deciduous teeth will be predisposed to impactions. The body’s response to impactions may lead to lysis, or breakdown, of the bones of the mandible or maxilla, which in turn may cause deformation of the face or a fistula into the sinus.
  
  It is not abnormal for horses to possess extra teeth, termed "wolf teeth," in front of the first upper cheek tooth, but they may be large, abnormally placed, sharp, or impacted and thereby become a nuisance. The presence of such teeth may cause injury to the soft tissues on the inside of the cheek or interfere with the bit when riding. Fortunately, these teeth have short roots and can be easily removed by your veterinarian to prevent any problems.

• Abnormal Occlusial Surface
  Because of the discrepancy in the width of the maxilla and the mandible, and the normal chewing motion required to grind feed, the surfaces of the cheek teeth wear abnormally. The outer edge of the teeth situated along the upper arcade and the inside margin of the teeth along the lower arcade are not ground down at the same rate as other surfaces and sharp edges form. The edges are sharp enough to lacerate the gums, tongue, and cheeks. The pain that results will cause additional grinding irregularities and further abnormal wear.
  
  Sometimes, the occlusial surface is worn so dramatically that a "sheer mouth" results. When the surfaces of the cheek teeth are viewed from the front of the mouth, the occlusial surfaces are overly obliqued, such that the maxillary arcade inner margins and mandibular arcade outer edges slope so extensively that they are worn to the gingiva.

• Trauma
  Trauma to the dental surfaces occurs quite easily in the equine species. Horses may damage teeth as the result of a kick from a fellow pasture mate. If the tooth is broken, treatment may not be necessary unless the tooth causes irritation or becomes infected, however, if a fractured tooth starts showing signs of disease or pain, extraction may be required. In such a case where the tooth is extracted or missing, overgrowth of the opposing tooth must be kept under control through regular, routine filing or floating.

• Dental Infections
  As stated previously, infections can occur when teeth are overgrown, malaligned, impacted, or fractured. Infections may manifest themselves as gingivitis, periodontal disease or tooth root infections. Left untreated, they may progress to more serious conditions such as bony infections of the jaw or maxilla as well as contamination and disease of the sinuses located near the affected teeth.

• Dental Neoplasia
  Fortunately, oral neoplasias are not commonly seen. There are several different forms, all with varying levels of malignancy. They may affect the bone or the soft tissues of the oral cavity. Sometimes, cancer of the sinuses may extend to or affect the function of the oral cavity as well.
  
  Depending upon the nature of the mass and its location, treatment can range from extracting involved teeth, surgical removal or debulking of involved tissue or bone (if possible), chemotherapy, or radiation therapy.

• Clinical Signs of Dental Disease
  The clinical signs of dental disease in equines are not much different than those seen in humans. Think about the changes you would experience in your own eating habits if you fractured a tooth. Horses with dental problems may experience a certain level of discomfort. In order to elude the pain, you might see a change in your horse’s eating behaviors, ranging from selective eating (eating grain but not hay), eating slower than normal, tossing food, dropping feed from the mouth, wadding masticated food and dropping it or carrying it in a cheek, tilting the head while chewing, or refusing to eat altogether.
  
  Some horses may eat without observable differences, but may demonstrate signs of discomfort while being ridden. The difficulty in such cases is in deciphering whether the behavior is brought about by dental pain, ill-fitting tack, or other lameness issues (such as spinal conditions or subtle limb problems), or if the horse is merely trying to evade training.
  
  If you notice alterations in your horse’s head carriage or if he demonstrates a preference to travel in one direction over another, he may have a dental condition that needs to be addressed. In addition, head shaking, stiffness concentrated around the head and neck, or a refusal to collect or contact the bit should all raise suspicions of the presence of a dental condition.
  
  Horses with a dental disorder may demonstrate some form of dysfunction secondary to the abnormality or pain. A horse with an irregular dental arcade may be unable to masticate its forages adequately, leading to wadding and droppage of feed. This in turn causes decreased food intake and weight loss. If the horse swallows these poorly masticated wads of food, esophageal choke could result.
  
  A horse with broken or worn teeth may demonstrate an increased sensitivity to cold, which may cause him to be reluctant to drink, especially in the winter. With the decrease in water consumption, the horse will be more prone to impactions and colic.
  
  Along with demonstrating behavioral signs of disease or dysfunction, horses with infections related to dental conditions may possess visible signs. For example, root abscesses or dental tumors may cause bony swellings to form, thereby enlarging the affected section of the horse’s mandible or maxilla. Horses with sinusitis secondary to a dental fistula or tooth root abscess may cough, drain fetid nasal discharge, or exhibit obvious facial deformations.

• Take Action
  It is recommended that you have your horse’s teeth evaluated by a veterinarian every six months. This way, abnormalities can be identified and corrected before they become a problem. In order to best evaluate your horse’s oral health, your veterinarian will conduct a thorough oral examination. If your horse has been experiencing dental problems, your veterinarian may ask questions about its recent history in order to better understand the disease process that is occurring. Less frequently, radiographs (x-rays) may be utilized to assist diagnosis.
  
  Many horses resist examination of the mouth. Inexperienced horses may be frightened by the awkward manipulation; while older horses may associate the handling of the lips and mouth with nasogastric intubation, oral deworming, or twitching. Your veterinarian cannot properly examine your horse’s mouth or address any abnormalities that may be present if he throws his head around or refuses to stand. For this reason, your vet may recommend that your horse be sedated for the examination and treatment to follow.
  
  Most veterinarians will utilize a mouth gag or speculum in order to thoroughly examine your horse’s dental arcade and provide treatment to teeth without risk to hands, arms, or expensive dental equipment. Handlers should use caution when a speculum is used as even a sedated animal may swing its head and strike an assisting individual with the metal device.
  
  If your veterinarian identifies malalignments or dentition abnormalities, your horse’s teeth may need to be floated (or filed). Motorized grinders and specially constructed files are used to level uneven surfaces and remove sharp points along the grinding surfaces. In order to provide adequate nutrition and avoid problems such as choke, veterinarians recommend that horses with severe malocclusions should be fed pelleted, formulated complete feeds that are easier to masticate than whole grains and hay.
  
  If your horse possesses one or more teeth that are malpositioned, he will require regular dental attention. Many malpositioned teeth can be maintained through routine preventative filing, although some may ultimately require cutting of the affected teeth or even extraction. Wolf teeth, as well as loose, fractured, or otherwise diseased teeth may also require extraction. Your veterinarian will discuss treatment options with you, as well as the advantages and disadvantages of each. Dental conditions that are ignored and left untreated may develop into more complicated diseases. For example, a simple infection may spread to the sinuses, become well-seated, and result in a chronic sinusitis. Such a condition is much more difficult to treat and is a significant health burden to your horse. Development of sinusitis may be unpreventable, but you should make every effort to address your horse’s dental health concerns as they arise to decrease the possibilities of occurrence.

Prevention and quick intervention are the keys to ensuring your horse’s oral health. Now that you are better prepared to understand the dental abnormalities that your horse can possess and the clinical signs for which to observe, you can help your horse to return to a healthy and effective "daily grind".