“He’s just got ‘old horse teeth’ doc!”
That’s usually the response from the horse owner or farm manager when I bring up the subject of an older horse’s diseased incisors. Yes, older horses have changes in the size, shape and orientation of their teeth, but broken incisors, “laid over” teeth, loose front teeth, and gingivitis are not a normal finding in an older horse. In fact, these are signs of a serious, painful disorder called “Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH).”
I know, it’s an awful name. I can barely spit it out myself and I sound like a pompous know-it-all when I do. Unfortunately, we’re unlikely to give it a newer, catchier name any time soon (gone are the days of naming diseases after fabulous descriptive terminology like “trench mouth,” “pizzle rot,” or “bog spavin”). Regardless of the tongue-twisting name, it’s extremely important that horse owners know the signs of this disease.
EOTRH is a newly recognized disease; it was only first identified in 2004. Since then, the veterinary profession has become increasingly aware of it. The condition involves proliferation (out-of-control growth) of the outer covering of equine teeth, called cementum (this is the “hypercementosis” part). In addition, many horses also have destruction of the internal structure of the teeth (the “resorption” part). As the disease progresses, the front teeth can become loose and crooked, or break off due to weakness and infection. In addition, the bone of the jaw can become infected.
This condition is obviously painful, and one of the first signs of the disease may be the horse’s refusal to bite a carrot or treat. Other early signs include drooling, decreased appetite, or abnormal behavior at the water trough (rinsing the mouth, dunking the muzzle, etc). Tapping on the teeth may produce a painful response. To diagnose EOTRH, we need to take radiographs (X-rays). Radiographs of affected teeth show bulbous root structures and dark spots inside the teeth, which indicate resorption.
At this point, we don’t really know what causes EOTRH. It’s still very new, so research is ongoing. In 2013, Arizona researchers published a study that offered some insight into risk factors for the disease. Management conditions, endocrine diseases and certain previous dental procedures were identified as some of the possible contributors. It’s way too early to fully understand how these risk factors actually predispose the horse to developing EOTRH, but new information will surely become available in the coming years.
So what do we do about EOTRH? Unfortunately, there are few treatment options. If the horse is in pain, removal of the affected teeth will restore his comfort. In some cases, removal of affected teeth may stop the spread of the disease to other healthy teeth.
Many horse owners are worried about extracting the horse’s incisors. It’s important to know that horses without incisors can graze and live a perfectly normal life. If all the teeth are removed, the horse’s tongue may hang out of his mouth, but this doesn’t seem to bother them! Living without some (or all) incisors is WAY better for the horse than suffering from chronic pain associated with broken teeth and infected jaws!
If your horse has any symptoms of EOTRH, have your veterinarian evaluate him for this condition! Radiographs (x-rays) will show changes, even early on in the disease. The sooner we are able to intervene in cases of EOTRH, the sooner the horse is out of pain!