Domestication of the horse has led to huge changes in his management and diet. Horse teeth erupt approximately 2-3 mm a year, but in the wild they would be worn down naturally by grazing for up to 16 hours a day on coarse, low nutrient grasses. A feral horse would have a life expectancy of around 12 years due to limited dentition - if a predator or parasites didn’t kill him first. Therefore it is important to look after the teeth, which in turn will help keep the horse healthy for longer.
Horses should be kept in as natural environment as possible e.g. 24 hour turn out and fed ad lib hay. However, this isn’t always practical or possible, so we generally provide processed feeds a couple of times a day with limited hay and turn out. This often results in dental issues and malocclusions (abnormal contact of upper and lower teeth). Concentrate/hard feeds reduce occlusal wear and range of movement, but teeth will continue to erupt at normal rate. Problems such as hooks, ramps, shear mouth, rotations and sharp enamel points can then form over time and will require dental attention. If left to progress these sharp cusps can easily cause soft tissue damage and ulceration.
A horse has a psychological and physiological need to chew, which helps maintain his physical and mental well being. A horse chews around 30,000 times a day, so it is essential that it can do so without being in pain. We can also feed from the ground, which is a natural position aiding normal biomechanical function and drainage of sinuses.
Ramps
Shear Mouth
Fractured Incisor (201)
No. An annual maintenance check and float should be a pain free experience. Horses are naturally nervous creatures and can become upset by change in routine or handler, but most will settle down for treatment without the need for sedation. Floating (rasping) the teeth can actually relax a horse, it is not the same as human dentistry – as with many things we tend to anthropomorphize.
An Equine Dental Technician is a lay person that practices dentistry. They are not veterinarians, but should have a good understanding of equine biology and be experienced horse people. Most EDTs will be more than happy to discuss their training and experience.
EDTs are often referred to as horse ‘dentists’, but legally only registered human ‘dentists’ can use the term, therefore we are titled technicians.
Most vets and EDTs will provide high standards of work and are up to date with advances in equine dentistry, but as with any profession there are a few ‘rogue traders’ that give EDTs a bad name. It is very important that vets and EDTs work together for the benefit of the horse.
My understanding is there are not enough equine vets to carry out dental procedures even if they wanted to, due to the high numbers of horses requiring other types of veterinary attention. It is estimated that there are 1.35 million horses in the UK, which is more than enough to go round!
A number of vets I have worked with are more than happy for proficient EDTs to carry out dental care as their speciality is in another area e.g. lameness.
Depending on the course taken most EDTs will generally be more advanced and up to date then vets who receive basic dental training on their degree course. However, some vets specialise in dentistry and are essential for advanced procedures. An EDT cannot sedate a horse or prescribe medication, but can assist a vet with surgery.
Basically, EDTs and vets need to work in conjunction with each other for the good of the horse, to educate owners and improve equine welfare.
The obvious reason is due to diet. Horses are herbivores and need to grind their fibrous food. Horses have ‘hypsodont’ teeth, which have limited growth, but erupt throughout the animal’s life. Humans being omnivores need to be able to chew meat and break down soft fibre, so they have ‘brachydont’ teeth which do not continue to erupt.
The equine tooth is made of the same substances as human dentition (cementum, enamel, dentine and pulp), but the matrix is different. Our teeth are encapsulated in enamel; where as the horse’s occlusal surface shows a cross section of all material except pulp. The three substances wear away at different rates due to different densities, providing uneven occlusal/grinding surface or self sharpening mechanism. These calcified dental tissues also lie in different directions, which gives the tooth its strength (like plywood).
The equine upper jaw (maxilla) is approximately 25% wider than the lower jaw (mandible). This can lead to sharp enamel rims forming through natural wear along the buccal (cheek) side and lingual (tongue) edge, which can cause pain.
Incisor cap (303)
Premolar caps & Wolf tooth (105)
Periodontal disease
Older horses are prone to dental problems as their teeth are coming to the end of their useful life. The teeth change shape with age as they narrow towards the root (apex). The gaps (interdental spaces) formed can pack with food and become an ideal breeding ground for bacteria. This can lead to gingival (gum) pocketing and ultimately periodontal disease, which loosens the ligaments anchoring teeth resulting in extraction.
The incidence of peridontitis increases with age, but can be prevented with regular dental care. However, there are many horses in their 30s with teeth better than horses half their age as they have been regularly maintained.
Youngsters often look like they have bumps or cysts along the jaw line, but this is usually skin distension caused by permanent teeth looking for space to grow and waiting for the skull to catch up! The skull alters throughout the horse’s life. The bones are dynamic and can reform as permanent teeth develop within the jaw.
A horse reaches full dental maturity around 5 years of age and has 36-44 teeth. As with humans, some horses are late developers, so permanent teeth may erupt at slightly different times depending on the individual.
Tooth Name | Tooth function | Number of teeth | Permanent teeth erupt |
---|---|---|---|
Incisors | Prehension & cutting food | 12 | 2 ½ to 4 ½ years |
Canines | Defence & fighting | 4* | 4 to 6 years |
Wolf teeth | Obsolete | 4* | 4 to 7 months |
Premolars | Grind food | 12 | 2 ½ to 3 ½ years |
Molars | Grind food | 12 | 1 to 3 years |
* May not be present
Each type of tooth has a specific function and classification. The Triadan system of nomenclature is used in all species, even humans. It allows lay dentists and veterinarians to discuss dentition accurately using a simple numbering method:
Human teeth are shiny and white as they are covered in enamel, but horse teeth are covered in cement. This is dull and porous, so stains easily. Horses that have regular access to fresh grass tend to have slightly browner teeth as the chlorophyll discolours the cementum.
It is down to the individual owner to decide if their horse goes better in a bit or a bitless bridle and there are pros and cons with both systems. It is sensible to obtain advice from your instructor and a bit specialist first www.informedbitting.com
If you decide to ride with a bit remember all horses are different and require a bit that is fit for the purpose and comfortable if animal is to perform to its best ability. It is important that teeth are well maintained as over erupted premolars can create pressure and wolf teeth will cause severe discomfort. Bit seats should be created as standard for the ridden horse as they help relieve pressure and reduce the risk of pinching tissue between teeth and the bit.
There is an enormous range of bits on the market and the type of bit used depends upon many factors including:
Today’s modern horse Equus Caballus has evolved over 50-60 million years. He started out as Eohippus, which was the size of a small dog, inhabiting forests and browsing on soft vegetation.
Equine dentition has evolved with the horse and adapted to environmental and dietary changes. Eohippus’ short crowned teeth (brachydont), experienced full molarisation in order to withstand grinding action required for successful mastication (chewing) of tough, abrasive prairie grasses when the forests retreated.
The horse evolved as a herbivore that relies on microbial digestion in the hind gut. It is not a ruminant able to re-digest its food and chew the cud like a cow. Therefore the horse has to rely on getting the most nutrients out of its food first time round. In order for digestion to be effective, the feed matter needs to be presented to the stomach in an easily digestible form - this is where good dental care helps. This simplified and lighter digestive system developed to allow for a large heart and lung capacity, providing the horse additional speed and stamina to out run predators.
The horse is a trickle feeder and cannot cope with large feeds as his stomach is small – approximately the size of a rugby ball. Hence, why they need food little and often and can graze up to 16 hours a day when kept in as natural environment as possible.
Evolution is still in progress today with redundant wolf teeth eruptions in gradual decline. Also some miniature horses have fewer molars due to over crowding, because of human intervention and selective breeding.