By: Rick S. Marion, D.V.M.
Hypercementosis is the name given to an emerging problem in older horses involving degeneration, and eventual loss of incisor teeth. The incisor teeth are the 12 teeth that sit in the front of the horse’s mouth, the ones seen when the lips are parted. They are used for biting and grabbing hay and grass but do almost no chewing, grinding, or processing of feed stuff. As we have all observed they sit perpendicular to the jaw in young horses and almost always become long and horizontal as the horse ages. The incisors can be severely affected by objectionable habits in the horse, such as cribbing or raking on solid objects.
Hypercementosis, more properly and recently renamed Equine Odontoclast Tooth Resorption and Hypercementosis (EOTRH) is a chronic degeneration of the incisor and canine roots. The degeneration of the root is accompanied by (or possibly caused by) inflammation of the periodontal membranes, loosening of the tooth, bacterial overgrowth, and gingivitis. The cause of this syndrome is not completely understood and it may be a combination of various syndromes with many causes alone or together, resulting in the same characteristic lesion.
The progression of the syndrome is inconsistent but typically begins with the corner incisor or canine teeth and progresses toward the center. As the teeth roots are variably reabsorbed and hypertrophied, the periodontal membrane becomes inflamed and infected, the gingival tissue also becomes infected, and the tooth loosens. Loose, inflamed teeth can be very painful but rarely will hinder the horse from eating.
Treatments vary tremendously, but as of now no treatment has been found to stop the degeneration and eventual loss of teeth. Antibiotics will partially control the gingiva and periodontal space infections. Anti-inflammatories, bute, banamine, aspirin, and steroids may help address the pain associated with the inflammation. Splints or braces may decrease the mobility of the teeth and also address some of the pain. All treatments will eventually end with tooth extractions. The incisors may be extracted one or two at a time as their roots fracture or the infection progresses enough to make removal necessary. However, they may all be extracted at one time to address their pain and to treat their condition as aggressively as possible.
Some veterinarians prefer to remove all the incisors at one time because they feel this more aggressive approach is the fastest and most complete way to resolve the pain, inflammation, and infection.