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Tom Elms- Equine Dentist

 

Why horse dentistry?
 
Horses require the same sort of routine dental care as humans, the only difference being they do not moan as much about it!
Dental care simulates the sort of wear they would get in the wild from eating course grasses, shrubs, and stems (1). To cope with this wear on the teeth, horses have evolved continually erupting ‘hypsodont’ teeth (2). These erupt 2-3 mm a year, which is about the same as a horse in its natural environment grazing 16-18 hours a day wears them down (3) This balance of attrition and eruption of the teeth is regularly effected by modern husbandry. Hard feeds and lush pasture mean our horse’s are not getting the wear to counteract eruption, producing dental malocclusions effecting performance and condition. Horse’s rely on bacterial fermentation in the caecum to digest their food, so if forage particles are larger than 4mm approx they will often pass through undigested) (2) General well being in our horse is also affected as trauma, sores or tooth pain from malocclusions can cause head shyness, development of bad habits and reduce a horse’s quality of life.
 
Signs of dental problems
 
Much of the time our horses suffer in silence until dental problems become serious. There are however signs that you may notice as an owner that can give away something’s not right. These are
• Loss of hard feeds from mouth
• Balls of food being dropped which is know as ‘quidding’
• Facial expressions during eating
• Raising the head in the air during eating
• Loss of weight/condition
• Undigested grains or hay in manure
• Squirreling: storing food in cheeks
 
There are also signs visible while riding, these can be.
• Difficulty in flexing to one side
• Head throwing
• Continually playing with the bit
• Rearing
• Tongue hanging out of the mouth or being visible through the lips
 

The young horse
 
At no other stage of your horse’s life is dental care more important than in the first few years. The young horse will loose 24 milk teeth and replace them with 36 to 44 permanent teeth up to 5 years of age (2).
It is recommended that foals are checked in the first few weeks of life so problems such as overbite (parrot mouth), under bite (sow mouth), wry nose, or congenital defects of the lips or palate can be sorted out while the bones of the jaw are still growing and can be corrected by veterinary treatment. If left unchecked these defects can affect suckling and development of your horse (5).
The young horse’s development can also be affected by problems within its oral cavity. Pain and dental malocclusions can distract it from it work or training, and bad habits which are difficult to eradicate later in life can develop under the influence of oral pain, such as letting it’s tongue hang out. Therefore prevention is recommended over a cure, as it will stop these bad habits developing.
During the period of up to 5 years, dental checks every six months are recommended. While annual checks are sufficient for adult horses as the teeth have attained their definite place in the mouth (5).
 
 
 Plate1. An example of the change that occurs in the young horses mouth. You can see permanent teeth, the top right erupting and the bottom left milk tooth falling out.
 
Young horse dental Issues
 
Below are some common problems associated with young horses,
 
Buccal/Lingual points
Horse’s teeth are anisognathic, meaning the upper teeth are around 30 % wider than the lower teeth (1). They are designed to grind laterally across each other breaking down cellulose in forage. Any asymmetry in the jaw, alignment of teeth or an incomplete chewing cycle can result in the development of sharp points of enamel on the teeth (5). These can cause soreness, lacerations and ulcers to the sides of the cheeks and the tongue. This pain can affect riding and feeding.
 
Wolf teeth
Wolf teeth are remnant teeth left over from 'thirty to sixty' million years ago when they were functional (4). They commonly erupt in front of the first upper and lower cheek teeth at around six to eight months (5) Wolf teeth can interfere with the bit and cause discomfort and pain as well as some feeding problems in these cases it’s recommended to have them removed by a vet or equine dental technician who has passed a Department of Environment, Food and Rural Affairs (DEFRA) approved exam (6).
 
Caps or Deciduous teeth
 
The transition from deciduous to permanent teeth can be a painful one for young horses if there are problems shedding (7). Sometimes a deciduous tooth can become retained between adjacent teeth, causing impaction of the permanent tooth coming through or conditions like periodontitis. This is caused by entrapment and decay of food between the deciduous and permanent tooth coming through (1).
Impaction normally occurs in the cheek teeth, and can be visible from the outside as ‘eruption cysts’ can form. These are an inflammation of surrounding structures, and are common at around three to four years as permanent teeth push through. Eruption cysts should disappear by the age of five as the cheek teeth have pushed up into mouth and are all in wear (5-2) The eruption times of teeth are also the most reliable way of aging your horse, these eruption times are detailed below.
Tooth Erupts In wear Erupts In Wear
1 6 days 6 days 2 ½ yrs 3 yrs
2 6 wks 6 wks 3 ½ yrs 4 yrs
3 6 mths 6 mths 4 ½ yrs 5 yrs
4’s - - 5 yrs -
5 6-18 mths - - -
6 Birth 6 days 2 ½ yrs 3 yrs
7 Birth 6 days 3 yrs 3 ½ yrs
8 Birth 6 days 3 ½ yrs 4 yrs
9 - - 1 yrs 2 yrs
10 - - 2 yrs 3 yrs
11 - - 3 yrs 4 yrs
Fig 1. Table to show eruption times of teeth in the young horse, deciduous teeth are in blue, permanent in red.
 
 
Plate 2. Example of eruption cysts on a three year old mare, these are normally no problem.
 
Excessive transverse ridges
 
Transverse ridges are a series of enamel ridges, which occur on the grinding surface of all horse’s cheek teeth. These are to cut up and break down forage, occasionally the rows of teeth are not correctly aligned causing sharp enamel points to develop and make a ridged appearance of the molars (6).
These excessive ridges need to be reduced back to normal levels as they can restrict the lateral movement during the chewing cycle and put pressure on temporomandibular joint, which articulates the lower jaw. Any soreness or damage here can affect riding as well as feeding (7).
 
Hooks and Ramps
 
These are caused by slight misalignment of the upper and lower cheek teeth and is often a result of an over bite or under bite, appearing commonly at the ages of seven and eleven years of age (7). Hooks occur were the tooth is not aligned; the opposing one does not wear it down, and it grows into a sharp hook (2).
They are most prevalent on the first or last upper molars, causing riding problems due to the fact that when your horse is going well on the bit, it’s lower jaw is relaxed and moves forward, hooks prevent this happening (2), and can cause pain in the turn as well as causing lesions and non-efficient feeding.
 
 
Plate 3. Example of a hook on the first upper premolar.
 
Ramps in contrast to hook’s, are a gradual rising of the whole tooth from front to back, where hooks involve only part of the tooth.
They occur normally in the first and last teeth of the lower jaw (2), and cause problems in the movement of the jaw and alignment of the teeth, which can lend to secondary malocclusions.
 
Over bite and Under bite
 
Over bite is commonly referred to as parrot mouth, and is when the upper incisors project out in front of the lower incisors (1). This can be corrected is the condition is picked up early by using a brace of surgical metal wire from the age of three months (2), this encircles the upper incisors and fixed onto the first molar.  A loose bite plate must also be fitted which is removed every time the foal is fed. This illustrates the importance of a dental examination within the first weeks of life.
Over bite is a common cause of hooks, ramps, and other cheek teeth malocclusions due to the misalignment of the whole jaw (5). Due to the lack of attrition from the incisors not meeting incisors commonly have to be reduced during dental treatment (2).
 
 Plate 4. A classic over bite due to misalignment of the upper and lower jaw.
 

Under bite or sow mouth is fairly rare in horses, this is when the lower incisors protrude in front of the uppers. It causes the same sort of problems as over bite and can corrected if found early in life.
 
Wry nose
 
This a shortening or deviation of the bones in the upper jaw and nose (1) producing asymmetry in the head and stopping the teeth fitting neatly together as well as producing breathing problems (2). Serious cases can be repositioned if spotted early in life. Milder cases can be controlled by routine dental care, as the poor alignment will cause cheek tooth malocclusions, and incisor problems such as diagonal bite (4).
 
Bit seating
 
This involves smoothing and rounding the first upper and lower cheek teeth, as the bit can push or pull soft tissue against them causing lacerations and ulcers if they are sharp. Good bit seating can remove this pain, reducing the risk of problems occurring during riding and biting. (4-2)
 

Dentistry legislation
 
As a horse owner it is important to be familiar with legislation on dentistry. The 1966 vet surgeons act made it illegal for people to diagnose or treat their own animals, but the Department for Environment, Fisheries and Rural Affairs (DEFRA), has since approved a scheme of categories which explains who is qualified to do what when it comes to our horses teeth.
Cat 1 procedures (7)
• Examination of teeth
• Removal of small points using rasps
• Removal of small dental overgrowths (max 4mm)
• Removal of loose deciduous caps
• Bit seating of first cheek teeth
 
These procedures can be done by anybody, further procedures can be performed by equine dental technicians that have passed a DEFRA approved exam, such as the British Equine Veterinery Association Exam. These are referred to as
Cat 2 procedures (7)
• Examination and recording of dental abnormalities.
• Extraction of teeth with no periodontal attachment must be by hand only.
• Removal of wolf teeth under veterinary supervision
• Use of motorised equipment to remove enamel points and reduce overgrowths in appropriately sedated horses
 
Cat 3 procedures (7)
• This basically includes everything else that could be done, such as extraction of teeth. These can only be done by qualified veterinary surgeons.
 

Case Study Ben 2 ½ yr old Gelding (9)
 
Ben was showing signs of discomfort and leaning on the bit, which was making his training as a sport horse hard work. After examination Ben was found to have all for wolf teeth present, as well as sharp enamel points on his cheek teeth.
 
 
Plate 5. Ben having sharp enamel points removed from his molars
All four wolf teeth were removed after sedation by the vet to alleviate his biting problems, along with two deciduous incisors from his upper arcade, which were stopping his permanent ones coming through straight.
 
 
Plate 6qa
 
Ben was cleaned up after the procedure and disinfected and after a well-earned rest was back to himself the next day!
Pictures, and information courtesy of kearsargemeadows.blogspot.com
 
Correct dental care can be the difference in your horse’s mood and welfare and shouldn’t be overlooked –
 
Regular dental checks are best commenced before your young horse is bited; it’s this period when it’s possible to set up your horse’s oral health for the rest of its life, as prevention is defiantly better than the cure when it comes to dentistry.
 

Useful information for owners
 
If you require any more information on dentistry for your horse these following books and websites are recommended.
 
www.beva.org
 
www.baedt.com
 
www.horsevetdirect.co.uk
 
British Veterinary Dental Association
www.bvda.co.uk
 
Equine dentistry, Easley et al 2011
 
Caring for the horses teeth and mouth, Chris Hannes 2009
 
 
 
 
 

References
 
Equine Dentistry, Jack Easley, Padraic. M Dixon, James Schumacher. Elsevier Limited 2011 (1)
 
Caring For The Horse’s Teeth And Mouth, Dr Chris Hannes. Trafalgar Square Books, 2009 (2)
 
The Horse & Pony Care Handbook, Amanda Lang. S.Webb & Son Ltd 2003 (3)
 
Oral Health In The Equine, Dale Jeffrey. 2009 (4)
 
Equine Dentistry, Gordon J Baker & Jack Easley. Harcourt Publishers Ltd 2000 (5)
 
www.horsevetdirect.co.uk (6)
 
www.baedt.com (7)
 
www.kearsargemeadows.blogspot.com (8)
 
ww2.defra.gov.uk/ -
 
www.horsedentistry.com (4)
 
www.kearsargemeadows.blogspot.com (9)