EOTRH in Horses Explained
EOTRH is a painful resorptive disease of the incisors in older horses. Learn the signs, how it is diagnosed with radiographs, and why extraction brings relief.
Quick definition: EOTRH (Equine Odontoclastic Tooth Resorption and Hypercementosis) is a painful, progressive disease of the incisor and canine teeth in older horses, where the tooth roots resorb while excess cementum builds up around them. It is most common in horses over fifteen, hides below the gum line, and is diagnosed with dental radiographs. Extraction of the affected teeth usually brings dramatic relief.
EOTRH is one of the most under-recognized dental diseases of senior horses, partly because its name is a mouthful and partly because the damage happens out of sight, below the gum line. Yet for the horses that have it, it is a constant source of pain that quietly erodes appetite, weight, and temperament.
The disease attacks the front teeth: the incisors a horse uses to nip grass and treats, and the canine teeth in geldings and stallions. Inside these teeth, the body\'s own odontoclast cells dissolve root structure, while the tooth lays down extra cementum in a failed attempt to stabilize itself. The result is teeth that become loose, bulbous, and exquisitely sore.
Why It Matters for Senior Horses
Age is the single biggest risk factor. EOTRH is rarely seen in young horses and becomes increasingly common past fifteen. Because horses are stoic and the front teeth are easy to overlook during a quick float, many cases go undiagnosed for years while the horse slowly stops enjoying food and grows grumpy or withdrawn.
Spotting the Signs
- Reluctance to bite carrots, apples, or other hard treats.
- Head shaking, head tossing, or resentment of the bit.
- Receding, reddened, or swollen gums and visible tartar at the gum line.
- Small draining tracts or pimple-like bumps above the incisors.
- Bulbous-looking teeth, loose incisors, or a generally sour attitude.
Diagnosis Relies on Radiographs
Because the resorption and cementum changes are hidden inside the tooth and root, a visual exam alone is not enough. Dental x-rays of the incisors reveal the extent of the disease and let your veterinarian stage it. This is why a senior dental workup that includes radiographs is so valuable, and why EOTRH is so often missed without them.
Treatment and Life Afterward
There is no treatment that reverses resorption, so the goal is to remove pain. For painful or advanced teeth, extraction of the affected incisors and canines is the standard of care and usually transforms the horse. Owners regularly describe a horse that eats with gusto, gains weight, and acts years younger within weeks of surgery. Horses graze and chew well even without incisors, since the cheek teeth do the real work of grinding.
For the clinical detail and aftercare, see EOTRH in senior horses. To keep the rest of the mouth healthy, read about dental care for senior horses, signs of dental problems, and tooth loss in senior horses. If your horse needs softer meals afterward, see feeding a horse with no teeth.
This page is educational and does not replace your veterinarian or equine dentist. Any suspected dental pain in a senior horse deserves a professional exam with radiographs.
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Frequently Asked Questions
What is EOTRH in horses?
EOTRH stands for Equine Odontoclastic Tooth Resorption and Hypercementosis. It is a painful, progressive dental disease that mostly affects the incisors and canine teeth at the front of an older horse's mouth. The roots resorb from the inside while extra cementum builds up around them, leaving teeth loose, bulbous, and sore. It is most common in horses over fifteen and is often underdiagnosed because the damage is below the gum line.
What are the signs of EOTRH?
Early signs are subtle: reluctance to bite carrots or hard treats, head shaking, dropping feed, or pulling back from the bit. As it advances you may see receding, reddened, or swollen gums, draining tracts above the incisors, calculus buildup, and teeth that look bulbous at the gum line. Some horses lose weight or become grumpy. Many owners only notice once a tooth loosens or breaks, so a dental exam is the surest way to catch it.
What causes EOTRH?
The exact cause is not fully understood. It appears to involve the body's own odontoclast cells breaking down tooth structure, with hypercementosis as an attempted repair. Age is the strongest risk factor, and it is more common in certain breeds and in horses with a history of periodontal disease. Mechanical stress on the incisors and chronic low-grade inflammation are suspected contributors, but EOTRH is not caused by diet or poor management alone.
How is EOTRH diagnosed?
Diagnosis combines an oral exam with dental radiographs. Your veterinarian or equine dentist looks for gum changes, draining tracts, and loose or bulbous incisors, then x-rays the front teeth to see root resorption and cementum buildup that are invisible from the outside. Because the disease hides below the gum line, radiographs are considered essential. Staging from the images guides how aggressively the teeth need to be treated.
How is EOTRH treated?
There is no cure that stops resorption, so treatment focuses on removing pain. For advanced or painful teeth, extraction of the affected incisors and canines is the standard approach and usually brings dramatic relief. Many horses eat better and brighten noticeably within weeks. Milder cases may be monitored with regular radiographs. Pain control and good periodontal care support the horse, but extraction is often the kindest long-term answer.
Can a horse eat normally without incisors?
Yes, and most do remarkably well. Horses use their incisors to nip grass and bite treats, but chewing is done by the cheek teeth. After incisor extractions, horses often graze with their lips and tongue and continue eating hay and feed comfortably. Owners frequently report their horse is happier and gains weight once the painful teeth are gone. A vet may suggest softening hard treats, but quality of life usually improves.
Is EOTRH painful for senior horses?
Very. The resorbing roots and inflamed sockets are genuinely sore, and horses are stoic, so many suffer in silence for months or years. Signs like a sour attitude, reluctance to take the bit, or fussiness over treats are often the only clues. This is why a thorough senior dental exam matters: relieving EOTRH pain, usually through extraction, is one of the most rewarding improvements you can make for an older horse.
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