Close-up on wolf teeth

A freshly extracted wolf tooth.
A freshly extracted wolf tooth.

Bryan L. Boone, DVM, takes a look inside the horse’s mouth at wolf teeth, which are estimated to be present in anything from  50 to 75% of horses.

Wolf teeth are the first upper pre-molars, and they are vestigial, which means they are not as fully formed as the other pre-molars and don’t really have a function in the horse today like they probably did thousands of years ago.

They are located at the back of the interdental space – the space between the incisors and the molars. Usually they are located just in front of the upper (maxillary) second pre-molar, which is the first tooth that actually looks like a molar. I’ve never seen a wolf tooth on the lower jaw (mandible), but there are reports in the literature of them being there.

A "rostral wolf tooth".
Wolf teeth are extremely variable in size, from being small pegs only 3 mm in diameter to having roots up to 2 cm long. In a small number of cases they may be “molarized” with a distinct irregular rim of enamel. Licensed via Wikimedia Commons

The bottom arcade is where the bit lies in most performance horses, but in racehorses the bit tends to be up in that interdental space and hits those wolf teeth in the upper arcade and can cause the horse problems.

Tradition has dictated that they are prophylactically taken out because occasionally they cause problems with the bit, which fits in the interdental space. Trainers don’t like horses to develop bad habits with their mouth, which can happen if the horse is uncomfortable with the bit hitting a wolf tooth. Trainers also don’t want to stop on a young horse’s training program to take out a wolf tooth that is causing problems. Probably 99% of owners have them taken out because they think at some point the wolf teeth will cause problems. I’m not sure it’s always justified, but as soon as you tell someone they don’t have to take the tooth out, it’s going to be the one that will cause a problem right before the horse is ready to make its first start.

So, wolf teeth are routinely taken out when the horses are two or under. Usually they have erupted or broken the surface of the gumline by then. Occasionally you have some that haven’t erupted, but you can feel where they are and usually see a reddened area where they will erupt. You do this procedure when you are floating their teeth and smoothing their pre-molars. In all, the process takes maybe 10-15 minutes per horse. Some can be hard to get out and be a more complicated process, but usually it’s not a long procedure.

In order to take them out you separate the periodontal membrane from the small tooth. It’s usually about a half-inch of tooth and three-quarters of an inch of roots. The biggest tooth I’ve extracted was about three-quarters of an inch long with roots an inch long. Even if they have not erupted, they need to be taken out. They can still interfere with the bit.

Once you have the tooth loosened, you can lift it out by using the second pre-molar as a fulcrum. There are some other instruments that go all the way around the tooth and cut around it, but that’s not the way I prefer to do it.

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I usually use sedation, but it’s not necessary. It just seems to facilitate the process and makes it easier on the horse, the handler, and the veterinarian. Also, the palantine artery lies along the inside of the upper arcade. If it is damaged it can bleed seriously, but it’s not life-threatening. That’s really the major concern in extracting the wolf teeth.

Invariably, veterinarians and owners get busy and we don’t get to the horses that need to have this done before they start training.

The horses that have trouble with their mouth – the horses whose wolf teeth really cause problems – are the ones that have wolf teeth that aren’t right against the second pre-molar. They are some distance away from that second pre-molar. I guess because of the space the wolf teeth are not protected by that second pre-molar. That lets the bit beat around on the wolf tooth and causes periodontal disease, inflammation, and soreness around the tooth. Those are the horses that the riders and trainers say need to be done right away because their teeth are bothering them.

This article, courtesy of the AAEP, was first published on Horsetalk.co.nz in 2005.

The larger wolf tooth on the left was taken from a six year old, It had been "blind" up to that year.
The larger wolf tooth on the left was taken from a six year old, It had been “blind” (present but not erupted) up to that year.

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