Open Up Wide and Say Ahhhhh

Today's blog post is all about horse teeth.  I have found some great photos online this week for equine dental issues and information.  This first one is of a horse tooth that was removed, root and all.  The horse was at Model Farm Equestrian in Liverpool, England.  They took a young horse with a tooth root abscess to the vet to have it extracted, and after the tooth was pulled they took a photo to show people what the whole tooth looks like.
https://m.facebook.com/modelfarmequestrian/

The part above the black line is what you would see if you opened the horse's mouth and looked inside, the part below the black line would be below the gums.  The root is really long on young horses!  On an older horse who had a tooth extracted the root would be much shorter, because as a horse ages and wears down the tooth by grinding it against food (and other teeth) it wears away.  The tooth will continue to grow (or "erupt") into the horse's mouth over the course of his life, replacing the tooth that was worn down.  So if this tooth had been removed from someone older it would have looked more like this photo from a 28 year old horse:
This photo came from http://www.equineelders.org/frequentexams.htm

Where in the horse's head does all this tooth fit?  It is an amazing system to accommodate so many large teeth, but a necessary one so the horse has enough tooth with which to eat over the course of his life.  This picture of a skull shows where those teeth and their long roots are stored in the upper and lower part of the mouth.

For those who need a little more perspective on how that looks, here is another image from Equus Magazine Nov 2006 that gives a better idea of where those teeth are stored when you look at a horse's face.  Notice how far back into a horse's mouth those teeth go.  The back tooth root goes all the way up near to the eye socket.

This last set of images I find extremely helpful to explain why you should do at least semi annual dental exams on young horses.  There is a misconception in the horse world that only elderly horses need to have their teeth examined and filed, or "floated".  I much prefer to have my young horses tended to early so that training goes more smoothly (more on that later) and then when they become elderly they don't need to have extensive dental work done because we addressed and thus prevented the problems early on in life.

If you look at the bottom right image of the horse with the normal mouth, you will notice that the teeth line up evenly. There is some roughening where the top teeth would meet the bottom teeth, but overall things look pretty even.  That is how you want the horse's mouth to look.  A young horse loses his baby teeth and his adult teeth come in at different times.  Because of this, each tooth begin to wear by grinding on the opposing tooth at a different time.  If the mouth is maintained with proper filing to reduce sharp points and keep things level, the mouth with stay looking mostly like the "normal" image. 

If the young horse doesn't have his teeth tended to early in life, the varying arrival times of the adult teeth can create the pattern you see in the top left image, called a Wave Mouth.  It's named for the wave-like shape you can see further back in the oral cavity.  Another issue that can stem from neglecting the young horse's teeth early on is the Step Mouth, seen in the bottom left image, where one tooth has gotten longer than the others, creating the shape of a step in those grinding teeth.  These abnormalities all make it very difficult for a horse to chew, and cause dramatic problems with bitting and riding, especially if you want the horse to reach his head and neck forward and down.  The Overbite seen in the top right image is partly genetic, partly maintenance.

All of these dental issues affect a horse's riding and training.  Unfortunately, riders often will overlook dental issues, not realizing that the horse' bottom teeth must slide smoothly against the top teeth in order to comfortably put his head down.  If there is a wave mouth, an overbite, or a step mouth, and you force the horse's head down, he must open his mouth so the teeth can get around each other and his jaw doesn't get locked into place.  When the mouth opens, the humans will often put a noseband on the horse in an effort to teach him to keep his mouth shut.  For example, as in the case of a dramatic overbite which has made significant hooks at the front and back of the mouth, it's not physically possible for the horse to put his head down with his mouth closed because his teeth are blocking the sliding of his jaw preventing it from moving.  Additionally, tying his mouth shut may even be forcing sharp teeth into sensitive tissues in the mouth, creating pain. 

There are many other things that can go awry in a horse's mouth, but these are the most common ones I see as I work with veterinarians on dental issues.  Thankfully a good equine veterinarian can resolve them if they are caught early and maintained, so next time you are wondering why a horse is high-headed or acting up, have the vet take a good look in his mouth.

For more information on fitting a bit to a horse's mouth you can watch this excellent video, which has thorough information presented by a veterinarian.
http://epona.tv/how-to-fit-a-bit-to-your-horses-anatomy#st_refDomain=www.facebook.com&st_refQuery=