In young horses, between the ages of two and five years, eruption of the adult teeth will be the most common problem. Frequently, it is not the eruption causing problems, but retention of the baby (deciduous) tooth particularly the premolars which are the first three cheek teeth. These baby teeth cap the adult tooth and are easily removed from a sedated horse.

As stated earlier routine hooks and points are an unlikely cause of chewing problems in horses. But when chewing problems develop it is a good idea to address these just in case. Points are sharp profections that develop on the outside edge of the upper cheek teeth and less frequently the inside edge of the lower cheek teeth. These sharp points arise from the ridges of enamel on the edges of the teeth. The upper arcade is wider than the lower arcade so as a horse chews he may not wear these edges smooth. Floating on a regular basis will prevent this problem.

A more difficult problem to deal with than points are hooks. Hooks form on the front edge of the first upper cheek tooth, the second premolar, and the back edge of the last, lower cheek tooth, the third molar. When first started these hooks are easily floated away, but as time passes and the hook becomes heavier and longer, it becomes more difficult to float and eventually cutting may be necessary. These hooks can limit the chewing motion and will accelerate the growth of the hook. Sometimes it seems as if P2 is a denser tooth, contains more enamel, and can in older horses wear the corresponding lower tooth down to the gum line.

For more on diagnosis and treatment see Dentistry and Floating the Teeth of Horses

Certainly the most common cause of a painful mouth comes with the horse aging. Horses have hypsodont teeth. Though the tooth quits growing by middle age, the tooth continues to erupt throughout the horses life. It does this by slowly pushing the tooth out of its socket as the socket becomes shallower. For many horses this means tooth loss by the time they are in their 20s. The problem is often exacerbated by the overgrowth of an opposing tooth causing premature wear and loss. There are several ways this makes a mouth painful and often it is accompanied by a bad odor.

Loose teeth often become infected and is a common event in older horses. As the tooth loosens, the remaining socket keeps the tooth in place. Food particles become trapped under the tooth and infection sets up. Besides signs of difficult chewing the horse there may be odor and the horse may start to quid: hold food boluses in the cheeks. Diagnosis is usually straight forward with a careful examination of the teeth which includes a manual exam where the teeth are palpated for looseness. These teeth are usually easily removed with minimal manipulation with an extractor or even manually with your hands.

Apical tooth root infections occur occasionally in the young to middle age and commonly in older horses. In one study of a large number of horses and using CT scans, could not find a cause in over half the cases examined. In those cases where a possible cause was identified, tooth fractures or periodontal disease was identified. In the past cheek tooth removal was an involved process best carried out under general anesthesia. However techniques have been developed for removal of cheek teeth that are still firmly attached yhat have fewer complications. The process does require special tooth seperarors and elevators and can be quite a long procedure sometimes divided up into several sessions. Sometimes following removal the alveolus is temporaily packed to reduce food contamination while healing.

Diastemata, are abnormal spaces between cheek teeth and common in older horses. Feed packs into these spaces leading to focal areas of putrefaction and in advanced stages local inflammation occurs. Odor in these cases is common. In severe cases gingivitis and periodontal disease results with the symptoms advancing to slow chewing, quidding, and weight loss. Cases without inflammation may not need treatment. Several techniques have been developed to address the advanced cases. Closing the space with dental materials have had mixed results. Drilling or burring has been used to widen the spaces between teeth to promote "cycling" of feed through the space and prevent fermentation. In one experiment where case selection allowed horses in with other severe abnormalities results were disappointing. However there is also a study of 9 horses with 21 severe diastemata, but no other abnormalities in the adjacent teeth, results were excellent. Approximately 2 mm were removed off the adjacent sides of the two effected teeth. Occasionally a repeat burring had to be done. Drilling requires specialized mechanical burrs to access the inter-tooth space. Treatment in these 9 horses prevented food collecting in the space, resolution of the clinical signs, and should stop further pathology from occurring.

A complication of long standing diastemata of the upper rear cheek teeth is the formation of a oro-maxillary sinus fistula and a chronic food contamination sinusitis. In a report of 9 cases those without loose teeth or other tooth pathology were successfully treated in the standing horse by flushing of the fistula and sinuses and repairing the fistula with polymethylmethacrylate. Flushing of the sinuses was done through a trephined entrance into the sinus to remove impacted food and inpisated puss and a saline and antibiotic mixture used. In those with tooth problems, removal of the tooth was necessary before filling the defect to successfully treat the problem.

Missing Teeth usually do not become painful unless the opposing tooth grows into the space and impinges on the opposite gum. When this happens rasping the long tooth back will usually provide relief. As teeth are lost effectively masticating forage becomes harder and the horse may develop changes in the way he chews to better masticate his food and he may begin to quid which means storing food in his cheeks, presumable to soften it and extract nutrients. By this time horses usually become more difficult keepers and suffer from weight loss, ...more

The joint that forms the jaw of the horse is called the temporomandibular joint and problems here are a rare cause of difficulty chewing. Fractures, infection, and arthritis have all been described. Other symptoms seen is some cases are swelling just below the eye, atrophy of the jaw muscle, decreased feed consumption (inappetence), a deviated jaw (mandible), and weight loss. Diagnosis has been based on radiography, endoscopy but computed tomography (CT) has been best at defining the nature of the disease.

The TMJ is located under the bold T.

Treatment for simple infection may consist of aggressive wide spectrum antibiotics with more complicated cases receiving surgical drainage and debridement using endoscopy. Recently cases of severe arthritis have been treated with surgical removal of the joint, called condylectomy along with removal of any necrotic material, often the meniscus. At greater than one year out the horses was clinically normal and eating well.