Flashcards in Equine Dentistry Deck (55):
What teeth do horses have and how are they named simply?
Wolf Teeth (P1)
Cheek teeth (P2-P4 & M1-M3
What type of teeth do horses have?
Hypsodont (high crowned teeth with enamel that extends past the gum line)
Describe the chewing motion of a horse, including where pressure is applied.
Horses have a lot of lateral movement at the TMJ. Their mastication occurs in a figure of 8 motion and consists of an opening stroke, closing stroke and power stroke which is where major pressure is applied at one side at a time!
What do the following teeth numbers correspond to? Give the arcade and the tooth.
a) Right top wolf tooth
b) Bottom left first incisor
c) Decidous tooth is preceded by the number '5'
note: The first number indicates the arcade and the second number indicates the tooth. The numbers go from 1-4 top right-bottom right (topR topL bottomL bottomR i.e. clockwise)
Why can a horse only grind on one side of its mouth at a time? What other adaptations of the mouth, with respect to arcade angles, are there?
The horse has anisognathism which means the maxillary arcade is wider than the mandibular arcade.
The occlusal surface is 10-15 degrees in angle and the teeth curve upwards at the caudal aspect which is called the 'curve of spee'.
What are the normal components of a tooth? Describe a difference in these components between maxillary, mandibular and incisor teeth in the horse
Cementum - holds the tooth to the peridontal ligament.
Enamel - hardest part of the tooth, laminated sheets
Dentine - makes up the bulk of the tooth, tubular structures
Infundibulum - infolding of enamel from the occlusal surface (full of cementum)
Pulp - blood and nerve supply
Maxillary teeth have 2 infundibulae
Mandibular have none
Incisors have 1
What is important to bear in mind when filing a horses tooth?
Horses have secondary dentine which normally protects the pulp and its movement down towards the root is stimulated by wear. Excessive filing of the teeth may expose the pulp which is counterproductive.
When might one perform an equine dental exam?
Annually - prophylaxis
Specific problems -
-Unilateral nasal discharge
What is quidding?
Taking in food, chewing but then spitting out the bolus. Would see a bile of half chewed boluses on the floor of the stable.
How is a dental examination performed?
Other physical exam (e.g. BCS)
Head exam (see lect for more info!)
What things are needed for an equine dental exam?
-Restraint/Sedation - if possible as gives a better idea of back of the mouth
What aids are there to diagnostic of dental problems?
What should teeth cheek teeth be examined for?
Molar table angle
Excessive transverse ridges
What aspect of the diet can lead to 'point' formation?
Chewing concentrates as this encourages a vertical chewing motion rather than a lateral chewing motion. Enamel overgrows and ulcerates parts of the mouth
What is 'shearmouth'?
This is when the occlusal surface is greater than 15 degrees, it results from severe enamel overgrowth.
How can shearmouth be treated?
Reduce buccal and lingual points
Reduce angle starting at the high side.
Treat regularly and
Treat underlying problems
What are the different types of rasp blade and their disadvantages/advantages?
Carbide chip - Cheap but robust and ok for routing work but harder to remove hooks
Tungsten carbide blades - expensive and brittle but excellent. Better for removing hooks than carbide chip blades
What are the basic types of rasp needed for routine work?
Straight head long length
Obtuse angle with length
Angled offset head of medium length
What care needs to be taken when using power tools for rasping?
The palatine artery! This runs 1cm medial to the upper cheek teeth!
How should remaining deciduous teeth be dealt with?
Remove with forceps or a screwdriver but be careful not to damage the permanent tooth behind it!
How do rostral and caudal overgrowths develop? Which teeth is this referring to (use number)?
Usually due to the rostral displacement of the maxillary arcade (parrot mouth). Affects 106, 206, 311, 411
How can hooks be distinguished from the curve of spee?
Run a finger over the back of the tooth to the gingiva behind it and if it feels sharp then it is a hook.
What can focal overgrowths be a result of and what can they develop into?
Can develop into wavemouth
Why does care need to be taken when removing overgrowths?
As overgrowths have reduced occlusal contact, and this is what causes the pulp migration of secondary dentine - need to be careful as reduced secondary dentine. Therefore these should be removed gradually.
How can pulp exposure be detected?
Probe secondary dentine overlying pulp horns. Also if when rasping pink filings are seen this could be pulp.
What can cause pulp exposure?
Can be due to reduced secondary dentine from overgrowths.
Apical tooth infections (can also be a consequence)
What is an infundibular cary and what can it lead to?
It is hyperplasia of the infundibulae. Can lead to a sagittal fracture of the tooth.
Should excessive transverse ridges of the tooth be reduced?
The normal height for these is unknown and removing the crown may not be great. If treatment is required then it should only be to remove INDIVIDUAL larger ridges whilst maintaining normal ridging.
What is periodontal disease?
Disease of the peridontum:
What is periodontal disease generally caused by in horses?
It is very rarely primary. Mostly caused by diastemata
Describe the pathogenesis of periodontal disease
Localised gingivitis leads to pocket formation. Trapped debris forms which stagnates producing VFAs that erode the periodontal ligament. The pocket is also deepened by compression during mastication. The alveolar bone is destroyed and bacteria enter the pulp cavity through root canals. (It usually begins between teeth)
What is diastemata?
When food gets trapped in a gap between tooth which puts pressure on the periodontal ligament leading to pain.
When is diastemata considered 'normal' and are there any factors that predispose to their development?
normal in aged horses
displaced teeth/overgrowths can predispose
Which teeth are more commonly affected by diastemata?
Caudal lower cheek teeth
How can diastemata be treated?
Widening the spaces or removal of the food.
How else can diastemata be managed?
Replace long fibre foods with short ones
Treat overgrowths that have resulted from the diastemata.
How can displacements of cheek teeth come about?
Congenital - arcades overcrowded during eruption.
Acquired - More common, lower 10s/11s in old horses
What can cheek tooth displacement lead to?
Diastemata and periodontal disease
How can cheek teeth fractures occur?
Secondary to infundibular caries.
What are the clinical signs of an apical tooth infection?
Aysymettrical jaw swelling
Vetral discharging tract
Submandibular LN enlargement
Is bilateral swelling indicitative of an apical tooth infection?
No bilateraly involvement is rarely pathological. It is more likely 'bumps' which form during eruption of the teeth.
How are apical tooth infections diagnosed?
Using radiography or ideally CT
What can cause apical tooth infecitons?
Pulp exposure due to excessive wear
Fracture exposing pulp
What is a problem with doing oral endoscopy on lots of horses?
It is hard to disinfect the endoscope.
What is the best way to take an oral radiograph?
Take it on a 45 degree ventral-lateral oblique
What is the most common cheek tooth to be affected by an apical tooth infection?
What is a voxel and how is a voxels hounsfeld unit helpful?
Voxel is a 3D pixel. A Hounsfeld unit can be used to work out what tissues are which
What are the radiographical signs of an apical tooth infection?
Periapical schlerosis or a periapical halo
Which tooth should be removed if a horse has a supernumary tooth?
The more caudal one
What is the only really good way of treating an apical tooth infection? What are the less effective ways?
Removal of the tooth is the best way.
Cutterage, antibiotics and endodontic treatment are less effective.
If repulsing a tooth, what aftercare is necessary?
Need to have frequent aftercare to prevent stepmouth.
What is a better method of tooth extraction than repulsion?
Extraction - this has 1/3 less complications than repulsion
Also, minimally invasive repulsion
Should lower wolf teeth be removed?
These are uncommon but may interfere with the bit so should be removed.
What should horses be vaccinated against when removing wolf teeth?