EOTRH in horses - a painful dental condition
Yesterday I was called out to treat a 26 year old welsh mare who was presenting with difficulty eating and a change in her ability to maintain her condition. The pony was also showings signs related to Cushings such as a hairy coat year round. The pony was sensitive around the mouth and nose area and reluctant to be examined, but after a few scratches and a bit of TLC she trusted me enough to perform her dental exam. On examination of the incisors (front teeth) I found extensive gingival recession and gingival hyperplasia - which is an overgrowth of gum tissue around the teeth. There was also evidence of draining tracts above the teeth which look like red marks or pimples on the gum. Her condition suggests Equine Odontoclastic Tooth Resorption HyperCementosis (or EOTRH). EOTRH is a painful dental condition which is usually seen in older horses. It is useful in understanding this condition to understand the following terms:
Odontoclastic – refers to the cells (odontoclasts) that are involved in tooth resorption
Resorption – the body’s internal process of destruction, disappearance, or dissolving of tissue
Cementum – the bone-like substance covering the entire surface of the equine tooth, protecting it and helping to anchor it to the jawbone below the gumline
Hypercementosis – abnormal, excessive formation of cementum
What is EOTRH?
The disease process occurs when the horse’s body resorbs the bone and tissue surrounding the incisor teeth (and sometimes the canine) root structures. As the horse loses more of his gingiva, feed causes infection in the gingival pockets. When this progresses, the periodontal ligament and alveolar bone that surrounds the tooth root is destroyed. After the tissue resorption and inflammation, the pulp of the tooth can become infected and cementum proliferates near the gumline. As it progresses the support structures of the teeth continue to diminish and the teeth become mobile or may even fracture. This process is very painful and affects the horse’s ability to eat.
While this disease has likely been around for many years it has only recently been properly diagnosed and named. When a horse is presenting with these symptoms then radiographs are required to evaluate the extent of the damage to the teeth in the way of how many teeth are affected and how extensive the lesions are. The treatment for affected teeth is extraction and although this seems like it may be radical, it is the only way to treat the condition and remove the pain to allow the horse to be able to return to a comfortable life.
Horses with endocrine conditions such as Cushings or equine metabolic syndrome (EMS) are up to 50% more likely to develop EOTRH than healthy horses. It is believed that the high circulating levels of glucose and insulin contribute to periodontal disease.
Signs to look out for
EOTRH can take many years to develop and horses are very good at hiding pain, so they may not present any outwards signs until the disease has progressed. The first sign to look out for is incisor pain. Difficulty grazing, or difficulty grasping treats like apples and carrots can be a giveaway that there is something amiss with your horse’s front teeth. Affected horses may also linger at their water bucket or exhibit “smiling” behaviour where they curl up their front lips repeatedly. Other signs of dental pain are head shaking, resistance to the bit, grumpy or unsociable behaviour, hypersalivation, poor appetite and weight loss. If your horse is exhibiting these signs it is very important to organise a dental exam with your equine dental technician (EDT) or dental vet.
Clinical signs of EOTRH that can be identified by your equine dentist or vet are as follows:
gingival recession or receding gumlines - teeth will look longer than they should or will be uneven lengths
deep pockets in the gumline where the teeth are losing attachment to the alveolar bone
gingival hyperplasia - an overgrowth of gum tissue around the teeth
drainage tracts above incisors which indicates infection
gingival hyperemia which is a reddening of the gums due to inflammation
bulbous appearance of the root structure underneath the gum, above the crown
petechia of the gums (small red dots) above the incisors
swollen and inflamed tissue around the top of the teeth
fractured or mobile (loose) teeth
pus drainage around gums or teeth
sensitivity or discomfort identified on oral exam
foul breath
visible resorptive lesions on teeth (holes in the teeth)
teeth with resorptive lesions visible (holes in the teeth, usually filled with feed)
Next Steps
This mare will now need to have some radiographs (X-rays) performed to determine the extent of the damage to the teeth and bone. I have contacted my vet who will then quote for the work and perform the X-rays to be able to give the owner a treatment plan. Please stay tuned for an update on her radiographic findings.
