Latest solutions to equine dental problems

The latest techniques and research are giving a bite to equine dentistry. You might not be able to teach your young horse to floss, says vet and dental specialist Graham Duncanson MRCVS, but widening diastemata – the small gaps between adjacent cheek teeth – can often make a huge difference to a horse showing signs of pain.

New techniques involving fitting braces to foals can help in some cases of parrot mouth. And, thanks to research at the University of Edinburgh, some horses suffering from decaying cheek teeth could now be candidates for fillings, using similar techniques and materials to those in human dentistry.

“A classic example for widening a diastemata would be the five-year-old who shows discomfort on eating, and quids, or spits out his food,” explains Graham.

“In a young horse, you might have one or two diastemata that cause problems, but not multiple ones, as with old horses. Older animals seem to cope with it, but young horses quite often get food trapped in there.

“This, in turn, causes gingivitis (inflammation of the gums), which leads to pain and spitting out of food.”

In most cases, the technique used is quite simple in qualified hands, and involves taking problem teeth out of contact with each other.

“I would rasp off just a tenth of an inch (2mm) from each tooth so they don’t meet”, explains Graham. “When the rotting food is cleaned out from the hole, that often solves the problem. If it doesn’t, we burr down between the two teeth using special diastemata burrs and widen the gap. It’s the equivalent of flossing.”

Grahamis also enthusiastic about work being done by researchers at the University of Edinburgh.

“They are working on infundibular necrosis in cheek teeth – teeth that are decaying,” he says. “This isn’t a new condition, it’s something that has probably always been there, but it’s only now that work is being done on it. Again, it’s seen more often in young horses that have got their full set of adult teeth.

“At Edinburgh, they are probing areas of necrosis very gently with dental picks. If they are shallow, they leave them alone, but if they go deeper, they drill out the decayed area and fill it with a material similar to that used in human dentistry.”

Graham says that the jury is still out on whether sugar can damage enamel. However, infundibular necrosis does not have a dietary cause. While a small amount of necrosis may be the norm, problem-causing quantities are relatively rare.

“From every thousand appointments, I would expect to see only three or four needing further attention,” says Graham.

While dental work has a higher profile, there are risks that it can be carried out too often.

“There are two things to stress,” says Graham. “First, that the horse only has three inches (7.5cms) of tooth to last him a lifetime and wears it down naturally at about one tenth of an inch per year.

“Because the first permanent check tooth comes into wear when he is about a year old, he has a natural maximum of 30 years’ worth – so if you are aggressively wearing teeth down too often, you are not helping the horse.

“Second, as the horse has evolved, so have his teeth. Things like transverse ridges, the irregular grinding surfaces, have evolved to make it easier for him as a grazing animal.

“Again, by taking them away, you aren’t doing him any favours and it’s something English vets don’t think is a good idea. Some US vet sand dentists grind them absolutely smooth, so when you put your hand in a horse’s mouth, it’s like running your hand over a set of billiard balls.”

There is also a myth, says Graham, that transverse ridges affect the horse’s ability to come into collection.

“Some people believe that the cheek teeth need to slide over each other,” he says.

“In fact, when the mouth is closed, the incisors meet but the cheek teeth don’t touch.”

Another American idea, the bit seat, is something that Graham looks on as a viable option in some cases. This involves burring back the teeth next to where the bit lies, to try and make the soft tissue sit more comfortably behind the bit.

“I don’t like the idea of the Texas bit seat, so called because everything that comes out of Texas is bigger,” he says. “But the Kentucky bit seat, which is smaller, can be a good option.

High-tech dental tools make the vet’s work easier, but only belong in skilled and qualified hands.

“There is some serious equipment available now,” he says. “And while you’re unlikely to over-rasp with the old-fashioned hand rasp, that can happen with an electric ‘powerfloat’, which is why it needs careful use and is only available to vets.

“Personally, I think that because of the dangers of electricity and water in the horse’s mouth, battery ones are safer.”

Management and feeding can promote good dental care. Graham advises feeding from the ground dand feeding long fiber, which will ensure that the horse’s teeth weaar correctly.

“If it’s a choice between feeding poorer quality long fibre and more hard feed, change to better quality long fibre and less feed.”

So what is the best dental routine for a horse, from cradle to grave?

“Foals should be checked soon after birth to see if they are parrot-mouthed,” says Graham. In some cases, new techniques involving the fitting of braces might be considered.

This needs to be done by the time a foal is about four months old, which is why a veterinary check soon after birth is so important.

If such techniques are not appropriate, the horse will need careful attention to dentistry throughout its life.

“If foals are normal, there is not much point doing anything until the two-year-old stage, when you need to check that dental caps are not causing problems,” says Graham.

“It’s also a good idea to get the horse used to the rasp, putting it in the mouth and moving it a little.

“Then check at six-monthly intervals in case dental caps are retained. The horse will have its full set of teeth by about 5½ years. From about seven to 12 years, you can often move to an annual check – though if there are problems at any time, you need to get them investigated.

“From 12 onwards, it’s generally best to go back to six-monthly checks. With the truly old horse, including those who lose teeth, good dental care can make a big difference to their health and condition.”

• This veterinary feature first appeared in H&H (9 September 2004)