BASICS OF HORSE DENTITION
Samantha Mixon, D.V.M.
Why does a horse need dental work at all?
For the same
reason you do, good health. Understanding anatomy plays a key role
in understanding how and why dental problems occur in the horse.
First, the upper jaw of a horse is always wider than the lower jaw.
So even in the best of equine mouths the outer edge of the upper
cheek teeth and the inside edge of the lower cheek teeth have no
opposing tooth to wear against. Therefore sharp points form on the
outside, or cheek surface, of the upper cheek teeth and on the
inside of the lower cheek teeth against the tongue. These points can
become so sharp that they cut cheek and tongue tissue causing
ulceration and scarring of the mouth. I often cut my fingers when
palpating the teeth during my initial exam. As these points become
larger they also prevent the natural lateral movement of the horses
jaw. The oral and dental anatomy of the horse is designed to rip and
chew roughage, browse and graze, for 18-20 hours a day. The natural
action of the jaw in a horse is to chew side to side in a circular
motion NOT to chew up and down as humans do. These points are the
most common problem inhibiting this normal chewing action but they
are only one of several abnormalities that lock a horses jaw and
force it to chew abnormally, up and down.
Secondly, a horse has 12 incisors, front teeth), and 26 to 30
premolars and molars, cheek teeth), as an adult. Looking at these
numbers it quickly becomes apparent to most horse owners that the
majority of their horse’s dentition is out of sight! This means that
the majority of dental and oral problems are also out of sight.
Horse teeth are hypsodont teeth, which means that they grow
continually during the life of the horse. Therefore they can
continually develop reoccurring problems or new ones as the teeth
grow. Humans, cats and dogs have brachyodont teeth which are one
size for life and wear as we age. Horses need good yearly Oral
Equilibration (returning the teeth to as normal contact as possible)
or their teeth will not be with them in their twenties. Good
thorough yearly dental care will extend the life of horse’s teeth by
approx. 5 years. Dental care should start in horses as yearlings to
prevent and correct problems and abnormalities.
Why does a young horse need it’s teeth examined?
Horses have 24 baby teeth called deciduous teeth that need to be
shed before their permanent replacements, adult teeth, can erupt
through the gum. Deciduous teeth that do not shed at the appropriate
time are called retained caps. Caps being the term equine veterinary
dentists give to baby teeth that should be shedding. A retained cap
in any location predisposes the mouth to numerous short and long
term consequences: (1) the eruption of the permanent tooth in an
incorrect location because the baby tooth is in the way; (2) delayed
eruption of the permanent tooth, causing malocclusion problems of
the incisors and cheek teeth; and last but not least, (3) severe
pain and discomfort resulting in eating and training difficulties.
The deciduous equine teeth are shed and replaced by adult teeth from
the ages of 2 to 5 years of age. Often I do not see a mouth until a
horse is 6 to 8 years of age. At this point I cannot prevent any of
the abnormalities caused by caps that were retained too long. All I
can do is start to correct the abnormalities over time, which may
take 2 years of corrective dental work every 6 months to correct.
Correcting is usually more time consuming and expensive for the
owner than preventing the dental problems in the beginning. Young
horses deserve excellent dental care for another very obvious
reason…THEY ARE IN TRAINING! Horses are put into training anywhere
from 2 to 4 years of age. These first experiences will leave a
lasting impression of how it feels to hold a bit in the mouth and
will mold the responses to human commands. Often a “bad” horse or a
“stubborn” horse is a horse trying to say, “This command /exercise
is causing me pain”. There is no excuse to start training off on the
wrong foot by putting the bit into a young tender mouth that has
very sharp points on it’s cheek teeth. Deciduous teeth form the same
very sharp points that the adult teeth do. The training messages
should be consistent and a pleasant experience for the new trainee.
The best program is to have a thorough dental exam and O.E.
performed when the wolf teeth are removed at the age of two. Start
your training off on the right hoof!
EVD: Equine Veterinary Dentist, a veterinarian who specializes
Hypsodont Tooth: A tooth that grows throughout the lifetime
of the animal. Found in horses and cheek teeth of ruminants.
Deciduous Teeth: Baby teeth of a horse.
Cap: A baby horse tooth that is about to come out, one that
needs to be lost before adult tooth can emerge in the right
Retained Cap: A cap that is not being shed in a timely
fashion and is causing abnormal eruption of an adult tooth.
Oral Equilibration: The correcting of dental abnormalities to
bring the teeth back into as normal contact as is possible for that