Josie Summers Bsc, BEVA/BVDA qualified, member of the British Association of Equine Dental Technician
07/02/2025
EOTRH stands for Equine Odontoclastic Tooth Resorption and Hypercementosis. 🦷
This is a painful and progressive condition that predominantly affects horses aged 15 years and older. It mainly affects the incisors and occasionally the canine teeth, but there has been some very rare cases of affected molar teeth.
The condition involves two primary processes:
Resorption: this is where the calcified dental tissue starts to break down by the horse’s own odontoclast cells reabsorbing the dental structures. This process is believed to be immune-mediated.
Hypercementosis: this is the development of excess cementum which occurs as the dental structures are reabsorbed. The body compensates by over producing cementum in an attempt to stabilise the tooth. This results in bulbous or club-like shapes forming at the apex of the tooth.
The presentation of EOTRH can vary greatly between horses. Some horses exhibit more dominant with hypercementosis, others are more dominant with resorption.
The disease may progress rapidly in some cases but slowly in others.
Due to its progressive nature, early clinical signs may be subtle or go unnoticed until the disease reaches an advanced stage.
Common symptoms include:
•Tartar buildup due to reluctance to use the incisors
•Bulbous dental structures beneath the gumline (caused by hypercementosis)
•Diastemata (gaps between teeth), leading to food entrapment, gingival recession, and periodontal disease
•Red, inflamed gums with draining tracts due to infection
•Loose, fractured, or missing teeth
•Halitosis
Affected horses often struggle to bite into carrots or pull hay from a haynet. Some may develop headshaking, and severe cases can lead to weight loss.
Diagnosis of EOTRH is confirmed through X-rays, which will reveal the extent of resorption and hypercementosis. Currently, the only effective treatment is the extraction of affected teeth by a vet. Each case requires an individualised approach depending on the severity of the disease. Horses adapt very well following extraction, and their improvement highlights the level of pain they were experiencing before treatment.
The cause of EOTRH remains unknown, current studies are exploring periodontal ligament strains, bacterial causes, occlusal pressures, and genetics, however it’s likely to be multi factorial. As our understanding of the disease grows with ongoing research we hope to develop more effective management strategies.
Regular incisor checks are super important to identify signs of EOTRH early. If you suspect EOTRH, consult your EDT or Vet, early intervention can help minimise discomfort for your horse!
