Dental Care
Blue
Sky Animal Hospital offers top-notch dental care for your equine friends.
Click the "Chew on This" link to the left for in-depth dental
information. Our doctor uses a
power float with safe sedation to minimize your horse's discomfort during the
floating. In addition to dental
exams every 6-12 months on adult horses they may require a floating just as
often, depending on age, dental structure, vices, and eating habits.
We can have your horse seen at the clinic if you prefer to trailer in or
we can make a house call for your convenience. Don't forget to have Dr. Johnson
check those teeth during vaccine appointments!
Ever wonder what your veterinarian is doing in
your horse’s mouth?
Don’t be hesitant to ask. Most of us would be happy to show or explain it to
anyone that has interest. First let us take a brief tour of the horse’s mouth.
Your horse has 42 hypsodontic teeth. The molar teeth have enamel ridges that
wrap around the cementum and dentin of the crown. The in-foldings of enamel
create pulp chambers called infundibula, which run throughout.
Horses grind their food in a circular motion. The crown is very long and the
teeth grow throughout their lives. You and I have short crowned brachydontic
teeth where the enamel covers the dentin on thecrown. We chew our food in a
pounding motion. The adult horse has six incisors on the top and six on the
bottom. These are numbered 101-103 on the right side on top and 401-403 on the
right side on the bottom. They are named I1, I2, and I3 on both sides and top
and bottom. Next is the pair of canine teeth numbered 104 on top & 404 on the
bottom. Then come four premolars 105-108 and named PM1-4. 105 is the “wolf
tooth”. The wolf tooth is usually present by 4 years of age on the top jaw or
maxilla. This tooth can also fail to erupt and remain just under the gum line
causing pain. Many trainers, veterinarians, and horse enthusiasts request that
the wolf tooth be removed to relieve behavioral problems caused by discomfort
from the bit. The wolf tooth also has a short, weak root that makes it sensitive
to the bit. The last three cheek teeth are the molars named M1-3 and numbered
109-111 on the top and 409-411 on the bottom. Remember that on the left side
they are named the same but numbered 201-204, 205, and 206-211 on the top, and
301-304, and 306-311 on the bottom. The missing 305 tooth is the PM1 on the
bottom that is usually absent. This would have been the opposing tooth to the
wolf tooth on the top had nature decided the horse needed it.
OK, enough
nomenclature, now we can talk about horse dentistry.
The front
deciduous teeth on a foal come in within a few weeks of birth.
The first incisor I1 erupts in about a week on the top and bottom. The second
incisor I2 is usually in by six weeks. The third incisors come in between 6-9
months. The first, second, and third premolars come in at the same time the
first incisor comes in. By 18 months the foal has 24 deciduous teeth.
The permanent teeth begin to come in at 28 months at the 1st incisor
positions, (I1) top and bottom. Then one year later the second incisors come in,
followed by the third one year after that. Many times the incisors will be
dislodged early by trauma, kicks, and falls. It is important to consult with
your veterinarian in these cases as this is the time to assess if the permanent
tooth is injured. We also need to correct malocclusions before the tooth has
completely erupted. These can create problems down the road if not addressed.
The canine teeth come in at four years, up to five years in some individuals.
The premolars, PM2, come in at about 32 months, 4 months later for the PM3 set,
and 8 months later for the PM4 set. The term “caps” refers to the retained
deciduous tooth overlying the permanent premolar. These interfere with normal
chewing. Impacted cheek teeth can lead to swellings on the face and jaw. These
should always be examined by your vet. The first molar M1 comes in by 1 year.
The second molar erupts by 2 years and the third between 2 ½ and three years.
One needs to allow for individual variation.
So how do horses survive in the wild without all this dental care?
The
feeding of grains increases the acid environment in the mouth compared to that
of the horse on pasture. The feeding of dry hay or sandy foods increases wear of
the teeth. Vices such as cribbing can also create abnormal and painful
situations in the mouth. The natural chewing motion of the horse is a large
eccentric circular motion. They do not chomp and chew like humans or dogs. They
grind their food in a circular grinding action. The weight baring is on the
incisors and TMJ joint. The molars are intended to just float. If wear or
abnormalities create problems such as slanting of the molar tables, hooks,
ramps, waves, and overbites, the horse cannot chew properly.
The horse
produces saliva as do many other animals. The saliva has a flushing action that
prevents feed stasis in the mouth. At rest, in a stall for instance, the saliva
flow is just enough for a moist intra-oral environment.
Chewing stimulates saliva flow. The horse can produce 50ml/min from the parotid
salivary gland. The average horse on range may graze 14 hours a day, thus
producing 40 liters of saliva. The saliva contains antibodies, buffers acids,
and mechanically cleanses the mouth, preventing gingivitis and periodontal
disease. When we feed a horse short meals, sweet feeds, and hard dry materials,
food stasis develops, followed by decay. Microscopically, decay begins in the
cementum. This is stage I. As decay progresses the enamel and dentin become
involved. This is stage II. Studies report that 70% of the nation’s horses over
15 years of age have stage I decay.
So, how
do
you know if your horse is experiencing these problems?
First, realize that asking your friend or even a veterinarian how old he or she
thinks your horse is does not replace a thorough dental exam. The mouth needs to
be flushed out and a clear visualization of the teeth performed. This often
requires a light source. Palpation of the jaw is also needed to detect swellings
and pain. Injuries to the tongue and cheek can help identify dental conditions.
As a horse owner, you may notice foul breath, head tossing, dropping grain or
rolled hay (quidding), refusing to take a lead, large pieces of undigested food,
facial swellings, and weight loss. Your veterinarian may pull the tongue to one
side to see the underside. It looks comical, but it is part of a thorough dental
exam.
What can be done if these problems exist, and why did they “float” my horse’s
teeth?
Having a
regular dental exam can identify problems when they are easy to correct.
Floating your horse’s teeth is a term used to describe the corrective leveling
of the molar tables. The goal is to regain the eccentric circular grinding
motion your horse is intended to have. When the horse balances
on the incisors and temporal mandibular joint, the molars just float as the
horse grinds its food. As the horse gets older the incisors tend to elongate and
wear in an extending manner which loads the molars. Floating involves reducing
enamel ridges that often form on the lingual (tongue) side of the bottom cheek
teeth, and buccal (cheek) side of the top teeth. Most veterinarians will create
a bit seat for you if you use a bit on the horse. The bit seat is a slope to the
rostral PM1 where the bit sits against that tooth.
Steps can form when a tooth is lost, or wears unevenly. This creates a lock on
the jaw and often reduces measial movement of the jaw. Corrective dentistry
refers to reducing points, waves, ramps, hooks, and other abnormalities.
Performance dentistry includes medications to treat periodontal disease,
fillings, cleanings, pulling wolf teeth, and other treatments to enhance the
horses comfort and health.
Finally, how can I prevent dental problems in my horse?
Feeding
horses off the ground will not only reduce sand colic and parasite transmission,
but puts less sand and grit in the mouth. Grazing on pasture and good quality
hay reduces feed stasis by using natural saliva production to cleanse the mouth.
Giving horses things to do and curbing vices can prevent abnormal ware. Keeping
the teeth in good approximation through dental care when needed will allow for
the natural chewing motions. I am reluctant to say don’t feed your horse sweet
feeds and sugary treats because clients enjoy giving these to their horses. But
consider giving carrots, hay cubes, and other low sugar treats. Also, increase
the forage ration of your horse to do a better job of flushing the mouth.
Jeff S. Johnson DVM
