Modern Equine Dentistry - Durham Equine Practice

Report
MODERN EQUINE
DENTISTRY
Why Equine Dentistry?
Routine dental care and oral health are important for your
horse’s health. Periodic examination for dental problems,
correction of wear problems and maintenance of healthy teeth
and gums is highly beneficial
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Poor dentition can lead to poor nutrition, weight loss, impaction colic
and reduced athletic performance (pain on riding)
Diets of many modern horses result in chewing patterns which are
different to natural grassland
We demand more performance and keep horses over a wider age
range than ever before
Breeding of horses has not selected for good mouth conformation
especially in particular breeds
Your horse’s teeth
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Horse’s teeth are continually worn down at the grinding
surface and the teeth emerge gradually throughout life
so that they stay the same length in the mouth
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This mechanism requires that the teeth are in perfect contact
with each other, otherwise growth is uneven and some teeth
become overgrown
Circular chewing motion in horses means that many
horses develop some sharp edges over time, which can
injure the cheeks, tongue or gums and make chewing or
contact with the bridle uncomfortable.
Dental Anatomy
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Foals are born with deciduous incisors and molars
These milk teeth are replaced with 36-44 adult teeth
between 2 and 5 years
Aged horses teeth wear out from 25-30 years of age –
become smooth or fall out
Surfaces of teeth have enamel ridges which slow the
rate of wear
Damaged enamel cannot repair itself
Dentine is a tissue inside the tooth which is laid down to
protect the live tissues – blood and nerve supply
Dental Anatomy
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The periodontal ligament and membrane attaches
the tooth to the jaw.
Dentine, pulp and periodontal membrane all contain
nerves which make them sensitive.
The pulp and periodontal tissues contain blood
vessels
 Because dentine is laid down
close to the surface of the tooth,
and contains nerves, it cannot
be assumed that horses do not
feel tooth rasping
Diet and Dentition
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Horses have evolved to eat grass (which is often fed as hay or
haylage now)
Grass contains silicates which causes wear at the grinding surface
Concentrate feeds cause less wear and in some cases reduced wear
may contribute to abnormal wear patterns
Horses pick up food including grass with the lips and incisors
The tongue pushes the food towards the cheek teeth
Food is crushed on one side of the mouth at a time in a circular
motion
Alteration in the chewing pattern due to pain or
overgrown teeth can contribute to abnormal angle of
the grinding surface of the teeth - creating a greater
problem over time (shear mouth)
Dental Problems
Common Dental Disorders
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Developmental disorders
Abnormal number of teeth – too many or few
 Abnormally placed teeth
 Abnormally shaped teeth
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Abnormalities caused by uneven wear
Acquired diseases
Trauma
Incisor Disorders
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Significant incisor disorders are less common than cheek
teeth disorders
This is because the incisors are less integral to the horse’s
health and ability to eat 
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The lips and tongue can be used to pick up food
Therefore horses which have abnormal incisor wear alone
are unlikely to lose weight
It is now known that incisor reductions (used to be done by
cutting top off tooth) can open into live tissues and
potentially kill the tooth.
Significant removal of incisor tissue is rarely warranted as
incisor problems are unlikely to affect chewing efficiency
(and are often secondary to cheek tooth abnormalities
which require correction)
Abnormal incisor wear
Smile mouth
Cribbing wear
Cheek Tooth Abnormalities
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Significant abnormalities more common than with incisors 
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Important to maintain cheek teeth to optimise feed utilisation
Abnormal wear and sharp points can cause painful ulcers of
the cheeks and tongue
Tooth fractures are relatively common
Diastema (spaces between the teeth) can allow food
packing at gum surface leading to painful gum disease
(periodontal disease)
Tooth root abscesses are painful and can lead to facial/jaw
swelling or sinusitis
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Interestingly they often don’t cause chewing problems
Dental decay (caries) are likely to cause pain and may lead
to tooth root abscesses
(27-39)
Signs of Dental Disease
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Difficulty chewing (+/- weight loss)
Chewing only on one side
Signs of pain when ridden
Resistance to the bit
Head tossing
(8-12)
Modern Dentistry
What’s new? Can my horse be treated?
Does he need treatment or management?
What’s new in Equine Dentistry?
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Interest among vets in producing quality research in
the field and evidence based medicine
Improved regulation of and qualifications for
Equine Dentists (see BAEDT for info)
Peer reviewed research must inform our diagnosis
and treatment in dentistry as in every other field of
equine medicine
Historical dogma is no substitute for science
What does this mean?
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Better understanding of dental anatomy
 E.g.
we must understand where blood vessels and nerves extend
to in teeth - to avoid damaging them through inappropriate
reduction of tooth overgrowths
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Better understanding of dental disease
We now understand that dental disease is painful and can
affect overall health
 Understand the way in which diseases progress over time –
 Put in place disease prevention strategies – from regular
checks, to management of overgrowths and diastema
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Advances in Dentistry
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Improved Diagnosis
Experience in equine digital dental radiography
 Use of mirrors and endoscopic cameras
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Allows earlier diagnosis, better treatment plans and more
accurate prognosis
Treatment evaluation
E.g. methods of removing cheek teeth have been refined
over last 20 years
 Some new treatments such as root canal treatments are still
being evaluated
 It is important to choose the correct treatment and the
correct person to perform it – as with any other type of
surgery or procedure
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Modern Equine Dentistry
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Advances in diagnostic equipment and techniques
New equipment and safer use of equipment
Improved knowledge of diseases and anatomy
Keep in mind chewing cycles and grinding surfaces
Improved knowledge of the effects (potential
consequences) of dentistry
Avoid risks associated with inappropriate treatments –
DO NO HARM
Modern Dental Examination
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Take complete relevant history
Examine head and mouth (and other body systems where
indicated)
Teeth
(41-61)
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Fractures and caries
Food packing, periodontal pockets and diastema
Abnormal wear
Loose teeth or loss of enamel ridges in aged horses
Normal eruption times, shape and number of teeth
Rest of mouth and head
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Ulcers, sores or other lesions of the lips cheeks and tongue
Swellings indicating possible tooth root abscess
Nasal discharge due to sinusitis associated with abscess
Result!
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Many horses when examined at an annual teeth
check do not require any intervention at all
This does not mean your vet is too tired to rasp
teeth!
It means you are lucky enough to have a horse with
good mouth conformation who is grinding food well
and maintaining his own teeth
In a survey of vets: Of 4925 equines examined
1483 needed no dental treatment
Some Dental Treatments
Removal of Overgrowths
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Sharp points on the sides of teeth can be removed
with hand rasps or power rasps
Care must be taken with power tools as it is easy to
remove more tooth than intended and it is also
possible to damage soft tissues if proper care and
restraint of the horse are not undertaken
Grinding surface of the tooth should not be touched
unless the individual tooth is causing a problem
Removal of Overgrowths
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Hooks due to parrot mouth, and overgrowths due to
uneven wear are usually removed using power rasps
unless very small
It is important to be aware that the live tissues can be
near the surface. It is safe to remove only 2mm
Further work can be done after about 12 weeks – the
live tissues will recede away from the surface and
dentine is laid down to protect them.
This is a normal response of the tooth which also occurs
as the tooth is ground down naturally
Fractured Teeth
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Commonly ‘slab’ fractures of cheek teeth in older
horses may not involve vital tissues
 They
may be found incidentally – no clinical signs
 Sometimes the displaced fragment may become sharp
and will then require rounding with a power rasp, or
removing if loose
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Fractures of incisors or other types of cheek tooth
fracture may require more complicated treatment to
try to save the tooth, or the tooth may require
removal
Tooth Removal
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Diseased teeth may need to be removed if fractured or if a
tooth root infection (abscess) is present
In young adult to middle aged horses this can be a very
difficult task as the roots are long and are usually still well
attached by the periodontal ligament
It can take hours to remove teeth in young adult horse
Teeth are usually removed from the mouth under sedation.
Sometimes anaesthesia is required and occasionally
repulsion (punching out) from the jaw is used
Once a tooth is removed its opposite number will require
management with power rasping over time, to prevent
overgrowth affecting the chewing action
Tooth Removal
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Removal of cheek teeth in younger horses is avoided
where possible due to the necessary ongoing
management required for the rest of the horse’s life
Complications can occur particularly in the back 4
upper cheek teeth on either side as the roots of these
extend into the bony walls of the sinuses of the head,
therefore care must be taken to avoid leaving a hole
between the mouth and sinus
Leaving a part of the root of the tooth can also cause
problems and prevent healing so this must be avoided
Diastema
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Spaces between the teeth that can lead to food becoming
packed and forced down between gum and tooth causing
damage and pain
Diastema should be carefully flushed under sedation to remove
packed food and allow the gum to heal. They are often packed with
a dental plug so that food is excluded
Some diastema require widening so that food is not forced into a v
shaped space (valve diastema) – widening to a U shape can allow
food to be removed by the tongue without causing a problem
Diastema widening needs to be done with care as there is potential
to damage the live tissues of the tooth
Diastema treatment is painful for the horse and deep sedation is
usually required
Excessive Transverse Ridges
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Enamel ridges are a normal part of the grinding
surface of cheek teeth
In some cases one or two teeth may have prominent
ridges which may drive food into the spaces
between the opposite teeth causing periodontal
food packing and gum disease (similar to situation
with diastema)
In these cases it may be appropriate to reduce the
enamel ridge (with a power rasp) to avoid or treat
this problem
Dental ‘Modifications’
Bit seating and Wolf Tooth Removal – Modern
Viewpoint
Bit seating
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Popular in disciplines such as dressage and polo
A notch for the bit at the front of the cheek teeth is
unnecessary as the bit should sit on the lower bars of the
mouth
There may be rationale in some horses for rounding of the
first upper and lower cheek teeth to prevent a soft tissue
fold becoming trapped between the tooth and bit
This is only usually required where a lot of bit strain is used
or a double bridle
Excessive bit seating is potentially harmful as the live tissues
are close to the surface at the front of these teeth
(59)
Wolf Tooth Removal
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Historically popular although there is little evidence of any benefit in
normally erupted, normally placed wolf teeth
Unerupted (blind), loose, or displaced wolf teeth may be sensitive if
contacted by the bit
Wolf tooth removal should be done with sedation and local
anaesthesia to avoid unnecessary pain
Legally only a vet or qualified EDT under continuous supervision of a
vet can remove wolf teeth. This is because of the need for pain
control and rare but potentially dramatic complications of wolf tooth
removal!
If done correctly there is no harm in removing these
Young horses may have lost erupted wolf teeth by the age of 3
because the eruption of the adult first upper cheek tooth can cause
the root to be resorbed and the wolf tooth may drop out all by
itself!
ANY QUESTIONS…
Or are you all asleep?
Did you know?
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FREE stuff from Vets, Well I
Never!
Most vets don’t charge for a basic oral examination to see if horse
needs sharp points removing at annual vaccination (or at other times
when we are seeing your horse)
Good equine vets will give an honest opinion as to whether any
work needs to be done or not
But please let us know in advance (if you can) if you want teeth
checking when we are doing vaccs (one of the reasons vets are
always late!)
We may not be more expensive than most dentists (certainly
qualified ones!) and we only charge an extra £10 for sedation if
required (unless the horse needs bucketloads!)
You only need to get together 4 people to have any type of work
done by us to benefit from a free yard visit (however we try to
avoid knowingly depriving other vets of their routine work so all
clients must ring to register with us BEFORE the visit)

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