Dr. Rick S. Marion

Hypercementosis PicHypercementosis is the name given to an emerging problem in older horses involving degeneration and eventual loss of incisor teeth in older horses. The incisor teeth are the 12 teeth that sit in the front of the horse’s mouth, seen when the lips are parted. They are used for biting and grabbing hay and grass but are not involved in the chewing, grinding or processing of feed stuff.  The incisors sit perpendicular to the jaw in young horses 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 20131227_102524tooth resorption and hypercementosis (EOTRH) is a chronic degeneration of the roots of the incisors and canines. 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 the syndrome is not understood and it may in fact be various syndromes with many causes alone or in concert resulting in the same characteristic lesion.

The progression of the syndrome is inconsistent, but starts with the corner incisor or canine and progresses toward the center. As the root of the teeth are variably reabsorbed and hypertrophied, the periodontal membrane becomes inflamed and usually infected.  When the gingival tissue becomes infected, the tooth loosens. Loose inflamed teeth can be very painful but rarely will stop the horse from eating.

Treatments vary tremendously but, as of yet, no treatment has been found to stop the degeneration and eventual loss of the teeth. Antibiotics will at least partially control the infections in the gingiva and periodontal spaces. Anti-inflammatories, bute, banamine, aspirin and steroids may address the inflammation and therefore the pain. Splinting or braces may decrease the mobility of the teeth and address the pain from that angle. All treatments will eventually end with extraction of the teeth. The teeth may be extracted one or two at a time as the root fractures or infection makes removal necessary, or may be done on all incisors to address the issue of pain and treat the condition as aggressively as possible.

There are veterinarians who prefer to remove all the incisors at one time thinking that this aggressive approach is the fastest and most complete way to resolve the pain inflammation, and infection.  Even with all the incisors extracted horses can comfortably eat grass and hold food normally.