X-ray image of a horse's teeth from the side of its mouth
Lateral X-ray of a 28-year-old horse showing a very large wave of the lower teeth due to dental disease and wearing out of the upper teeth.

Caring for your horse’s teeth is a lifelong commitment, and it becomes particularly important as they get older. Equine teeth are very different from the teeth of humans, dogs, and cats, because they continually erupt into the oral cavity over the lifetime of the horse. As a result, horse teeth have very long crowns with comparably short roots. In a young, normal-sized horse (think typical Thoroughbred), the full length of a tooth can be up to 4 inches (10 cm) long! Over time, these long teeth are worn down by grinding against other teeth in the mouth as the horse chews and eats grass or hay. To keep the top and bottom teeth in contact with each other, teeth erupt into the oral cavity at a rate of roughly 3-5mm per year.

As a horse approaches old age, teeth begin to wear out, meaning there is less and less crown left to erupt into the mouth. Old teeth can wear out at different rates, often causing a mismatch in tooth length, which can eventually lead to malocclusion – or misalignment – of the teeth.

An example of malocclusion is “wave mouth” where the upper teeth contact the lower teeth at different heights, causing vertical misalignment that looks like a wave formation when viewed from the side of the mouth. Old horse teeth also carry a lifetime of wear and tear, which can lead to dental diseases like tooth fracture, deep dental cavities, and loss of the gum tissue and supporting bone (periodontal disease). Malocclusion can also lead to soft tissue ulceration. Wave mouth and dental disease can be painful and disrupt normal chewing and eating behavior in senior horses, which can lead to weight loss or an inability to maintain a healthy weight, particularly in the wintertime.

Equine dental exams help prevent disease

Routine oral examinations are key to recognizing dental disease before it starts to cause pain, malocclusion, and trouble eating. We recommend that horses over the age of 18 have oral examinations at least once a year. If there is any sign of a malocclusion, missing teeth, or dental disease, we recommend oral examinations every 6 months until the malocclusion and/or dental disease have been treated or managed.

Senior horses with Cushing’s disease are also more likely to have signs of periodontal disease. Cushing’s disease can disrupt normal oral healing and impair immune system function, leaving oral structures and teeth more susceptible to inflammation and infection. If your older horse has Cushing’s disease, oral examinations should be performed every 6 months.

gloved hand holding endoscope inside horse's open mouth
Oral endoscope in use during a routine equine dental examination.

At the CSU Johnson Family Equine Hospital, routine equine dental exams include a complete physical examination, sedation, close examination of the head, dental speculum placement, examination of each tooth with a video endoscope or mirror, and a dental float and/or X-rays if needed. A dental float includes filing down abnormal tooth structures like sharp edges (called enamel points) and overly long teeth causing malocclusion. Examination of every tooth with a video endoscope or dental mirror allows veterinarians to see dental structures up close to determine if any disease is evident and/or malocclusion exists. In a senior horse’s mouth, there is typically lots of wear and tear to observe and treat in addition to sharp enamel points and malocclusion. If these disease processes and malocclusion are caught early, then management and treatment will be easier and less invasive.

Signs of dental problems in horses

The most common sign that a horse has dental disease is…no sign at all! Horses are extremely good at hiding pain and discomfort in the mouth. Many horses can continue to eat and maintain their weight even with advanced dental disease and malocclusions, which is why scheduling routine oral examinations is so important. With more advanced dental disease, horses can show clinical signs.

Signs of dental problems in horses include:

  • Resistance to biting and work
  • Head shaking
  • Dropping feed (“quidding”)
  • Inability to chew hay
  • Delicate grasping of hay
  • Slow eating
  • Reluctance to drink cold water
  • Weight loss
  • Chewing only on one side
  • Disinterest in treats
  • Bad breath (halitosis)
  • Nasal discharge
  • Facial swelling
  • Drooling
  • Eating with the head tilted to one side

If you notice any of these signs, schedule an oral examination with your veterinarian.

Senior horses don’t need to have bad teeth. Scheduling routine equine dental exams and dental floats with your veterinarian is the best way to ensure that your older horse has a comfortable and functional mouth. If you would like to schedule an oral examination for your horse, contact our Equine Dentistry and Oral Surgery service.