Horses are herbivores which have adapted to eating fibrous plant material such as grass. During normal grazing behaviour the grass is grasped between the top and bottom rows of front teeth (the incisors) and passed backwards in the mouth by the muscles of the tongue and lips. Here the grass is ground down into small pieces between the rows of powerful cheek teeth. This crushing of food is powered by huge muscles on either side of the jaw. You will all be familiar with the grinding sound your horse makes as its teeth crush its food.
Humans’ teeth are covered all over in a hard substance called enamel (the hardest substance in the body) which resists wear. The wear surface of horses’ cheek teeth is made of several substances: enamel, cementum and dentine. These substances have different hardnesses and so wear at different rates. The result is a very irregular or ridged surface to the teeth, a perfect grinding surface.
Despite having very hard teeth, such repetitive grinding slowly wears the teeth down. Horses cope with this by having reserve tooth under the gum line which is pushed out slowly over the horse’s lifetime (about 2 to 3 mm of tooth per year). This is different to humans whose permanent teeth do not continue to erupt during life.
When we stable horses, reduce their access to forage or give them cereal based feeds, their chewing activity changes. It makes them more likely to develop abnormal wear to their teeth, most commonly in the form of sharp edges.
Horses have different types of teeth.
The incisors are the teeth at the front of the mouth. There are a total of 12 incisor teeth, six in the bottom jaw and six in the top. All of these teeth appear in young horses by 6 to 9 months of age as milk teeth (deciduous teeth). These milk teeth are gradually pushed out and replaced by adult or permanent incisor teeth as the horse ages. In most horses, these have all appeared by 4 1/2 years of age. Adult incisor teeth tend to appear at quite predictable time points and can be used, in conjunction with other changes in the appearance of the teeth, to provide an estimation of a horse’s age. This estimation is relatively accurate up to about 6 years of age, after which the technique becomes increasingly inaccurate.
The canine teeth or tushes. These are the pointed teeth found in the bars of the mouth between the incisors and the cheek teeth. They are much more common in male horses, appearing at 4 to 6 years of age. These teeth are similar to human teeth and do not continue to erupt over time. Unlike carnivores, the canines of horses’ mouths tend not to rub together as the mouth opens and closes. This makes them prone to accumulating tartar (a build up of irregular, yellow deposit around the base of the tooth).
Wolf teeth. Many thousands of years ago, the descendants of the modern horse had an extra cheek tooth. As the horse evolved, this first cheek tooth shrunk, leaving a small rudimentary tooth referred to as the wolf tooth. Wolf teeth are found in front of the first cheek tooth. They are not present in every horse. They vary in size from a few millimetres to several centimetres from crown to root. The teeth are more common in the upper jaw. Wolf teeth sometimes cause problems during riding and bitting and can be removed by your vet. Not all wolf teeth cause problems.
Cheek Teeth. There are a total of 24 cheek teeth in an adult horse. They are arranged in four straight rows of 6 teeth. The first three (counting from front to back) are premolar teeth. These teeth, like the incisors, first appear as milk teeth that are pushed out by the adult teeth. These milk teeth are known as dental caps. Most horses lose their dental caps spontaneously as the adult teeth erupt.
The back three teeth are molar teeth. These teeth do not have milk teeth.
As they look similar, premolars and molars are referred to simply as cheek teeth.
The upper cheek teeth are wider and the rows wider apart than the lower cheek teeth. This produces a natural slope to the surface of the teeth. A common result of this arrangement of teeth is the production of sharp points on the outside of the upper cheek teeth and the inside of the lower cheek teeth.
Horses suffer a large array of dental conditions, just like humans. Signs of poor or painful teeth vary from dropping food and weight loss through to behavioural and riding problems.
It is important for your horse to have a thorough dental evaluation by a Vet or qualified Equine Dental Technician (EDT) at least once every 12 months.
There are lots of people who rasp horses’ teeth. Some are totally untrained, have inadequate equipment and do poor work. The British Equine Veterinary Association (BEVA – see links page) has developed a training programme, an examination and a qualification as an Equine Dental Technician. This qualification allows horse owners to recognise who is qualified and recommended by BEVA to carry out dental work.
The frequency of the examination will depend on the individual animal. Young horses should also be checked because problems can occur when the milk teeth are developing or are being replaced by the permanent teeth.
Your vet or EDT will always use a special gag ( Hausmann gag). This has a metal ratchet system which keeps the mouth open and is placed between the incisor teeth. They will look at and feel the teeth and, if appropriate, will carry out treatment. This is usually some form of rasping. They should be willing to discuss treatment with you and can supply a dental record chart.
Your annual vaccination date is an excellent time for your horse to receive a dental check. An advantage of your veterinary surgeon performing the dental work is that some horses require intravenous sedation to allow the work to be performed effectively. Only vets can administer intravenous sedation. We are also happy to sedate horses for treatment by BEVA qualified EDT’s.
Chine House also offers clients a full dental diagnostic and surgical service. An important development at the hospital has been the installation of internal stocks to carry out some of the more invasive procedures required, including cheek tooth extractions and standing sinus surgery.
Ridged grinding surface of equine cheek teeth
Upper and lower jaw of a horse
Horse wearing a Hausmann Gag for dental examination
Dental work being carried out in our indoor stocks
A selection of dental instruments
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