Cracks in cheek teeth of horses increasingly recognized, say researchers

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Researchers found no clinical signs associated with almost half the cracked cheek teeth identified in the British study.
Researchers found no clinical signs associated with almost half the cracked cheek teeth identified in the British study.

Non-traumatic cheek teeth fractures are increasingly recognized in horses, according to researchers who just examined the issue in a study.

Most equine cheek teeth fractures occur in the absence of known evidence of trauma. They most commonly affect the teeth in the upper jaw.

Fracture sites can fill with food, which, along with chewing movements, displaces smaller or more mobile dental fragments which can cause problems to softer tissue. Mouth pain can arise, with resultant quidding, loss of appetite, problems with fitting a bit, or headshaking.

Loss of these tooth fragments, or their extraction, usually resolves the oral pain.

If exposed pulp from a crack is not sealed off with tertiary dentine, infection may result, causing further problems for the horse, including nasal discharge and a swollen jaw.

University of Edinburgh researchers Padraic Martin Dixon, Rebekah Kennedy and Richard Reardon, in a study reported in the journal Frontiers in Veterinary Science, set about investigating the issue in horses.

The trio examined the clinical and imaging records of horses undergoing dental examinations (some on multiple occasions over many years) at the university’s equine hospital between 2010 and 2018.

They looked for the presence of non-traumatic cheek teeth fractures, where there was no history or clinical evidence of these fractures being caused by external trauma or illness-related damage.

The diagram on the left shows the fracture plane through both infundibula (that would have advanced caries and likely coalescence of both infundibula before fracturing).
The diagram on the left shows the fracture plane through both infundibula (that would have advanced caries and likely coalescence of both infundibula before fracturing). The top right image shows a transverse computed tomographic image of an aged Triadan 209 with a midline infundibular caries-related sagittal fracture (arrow) with resultant apical infection and maxillary sinusitis (star). The bottom right image shows a postmortem image of an infundibular caries-related midline sagittal Triadan 109 fracture with palatal and buccal displacement of the two fracture fragments and food impaction in the fracture site (arrow). Image: Dixon et al.

Horses with only hairline cheek teeth fractures were not included in this study.

Their investigations revealed that the 300 horses had 486 non-traumatic cheek teeth fractures between them, with 77% in the upper jaw and 23% in the lower jaw.

This amounted to an average of 1.6 such fractures per horse. A single fractured tooth was present in 206 horses, two in 59 horses, three in 16 horses, four in 10 horses, five in 5 horses, six in 3 horses, seven in 3 horses, and 10 fractured teeth in one horse.

No clinical signs were noted in horses with 48% of the fractured teeth, while oral pain or quidding was recorded in 26% of cases, clinical apical infection with 23%, and bitting/headshaking problems with 6%. Treatments included extraction of 40% of fractured teeth, extraction of small/loose fragments (10%), and odontoplasty (enamel shaping and recontouring). The stable remnants of 60% of fractured teeth were left in horses without clinical signs.

The authors noted that the frequency of extractions differed significantly between the type of fracture present.

One horse, in particular, warranted special mention. It was first seen with multiple cheek teeth fractures when aged seven, and was examined 25 times over 13 years, including the duration of this study.

Over this time, it developed six cheek teeth fractures in its upper jaw and one in the lower jaw. Over this period, clinical signs indicating possible dental disease were recognized only five times. These included nasal discharge due to sinusitis, surprisingly with no dental involvement.

The authors said non-traumatic cheek teeth fractures are increasingly recognized in horses, with almost half of those identified in this study showing no clinical signs.

“Fractured teeth with apical infection, which includes most teeth with infundibular (funnel-shaped) decay-related fractures, and those with multiple fractures or advanced decay, require extraction,” they said.

Most other teeth do not necessarily need immediate extraction, they said, and most can remain in place for many years without causing clinical signs.

Dixon PM, Kennedy R and Reardon RJM (2021) Equine “Idiopathic” and Infundibular Caries-Related Cheek Teeth Fractures: A Long-Term Study of 486 Fractured Teeth in 300 Horses. Front. Vet. Sci. 8:646870. doi: 10.3389/fvets.2021.646870

The study, published under a Creative Common License, can be read here

 

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One thought on “Cracks in cheek teeth of horses increasingly recognized, say researchers

  • May 30, 2021 at 7:16 pm
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    Has any correlation been made to the use of metal bits in horses mouths and frontal molar fractures?

    Reply

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