DENTISTRY - Equine Dentistry Flashcards
What is the equine permanent dental formula?
3-1-3(4)-3 / 3-1-3-3
How do you label equine teeth using the Triadan System?
The Triadan System describes each tooth using three digits, with the first digit referring to the quadrant in which the tooth is located. 1 refers to the upper right, 2 refers to the upper left, 3 refers to the lower left and 4 refers to the lower right
What does the occlusal surface refer to in dentistry?
Occlusal refers to the surface of the teeth in contact with the opposing teeth
What does apical refer to in dentistry?
Apical refers to the area of the tooth furthest away from the occlusal surface
What does lingual surface refer to in dentistry?
Lingual refers to the medial surface of the lower teeth
What does palatal surface refer to in dentistry?
Palatal refers to the medial surface of the upper teeth
What does buccal surface refer to in dentistry?
Buccal surface refers to the lateral surface of the upper and lower teeth
What does labial surface refer to in dentistry?
Labial refers to the rostral and rostrolateral surfaces of the upper and lower incisors and canines
What is the clinical crown?
The clinical crown is the erupted portion of the anatomical crown the tooth
What is the reserve crown?
The reserve crown is is unerupted portion of the anatomical crown of the tooth
What are the two subdivisions of the reserve crown?
Alveolar crown
Gingival crown
What is the alveolar crown?
The alveolar crown is the portion of the reserve crown located in the alveolus
What is the gingival crown?
The gingival crown is the portion of the reserve crown that has erupted from the alveolus but still remains sub-gingivally
What is hypsodont dentition?
Hyposodont is a pattern of dentition characterised by teeth with high crowns and prolonged eruption to allow for continuous attrition (wear)
How much do equine teeth wear annually?
Equine teeth wear 2 - 3mm per year
What are the six main anatomical components of hyposodont teeth?
Dental pulp
Enamel
Dentin
Cementum
Periodontium
Infundibulum
How does the structure of dental pulp differ in horses?
At eruption, equine permanent teeth have a large common dental pulp, however, over time the pulp develops into seperate pulp horns
What is type 1 enamel?
Type 1 enamel is composed of rows of enamel prisms and this is very strong against wear resistance, however there is an increased risk of cracking along interprimatic lines
Where is type 1 enamel found within equine dentition?
Type 1 enamel is found in greater abundance in the cheek teeth, where high wear resistance is required
How is enamel structured within the cheek teeth?
The cheek teeth have peripheral infoldings of enamel and the upper cheek teeth have two enamel containing infundibula. This structure increases the surface area and creates a more irregular occlusal surface for grinding
What is type 2 enamel?
Type 2 enamel is composed of interweaving bundles of enamel prisms, making it very strong and less likely to crack under conditions of high mechanical stress
Where is type 2 enamel found within equine dentition?
Type 2 enamel is found in greater abundance in the incisors where the teeth encounter high mechanical stress
How is dentin structured within equine dentition?
Dentin is interspersed between enamel, creating an irregular occlusal surface through differential wear compared to the harder enamel
What are the three classifications of dentin?
Primary dentin
Secondary dentin
Tertiary dentin
How does primary dentin respond to local insults?
Primary dentin responds to local insults by developing sclerosis to prevent microorganisms from gaining access to the dental pulp
What is the function of secondary dentin?
Secondary dentin is laid down in the periphery of the dental pulp through most of the life of the tooth, preventing exposure of the pulp during normal wear. Furthermore, secondary dentin absorbs pigments from foods, giving it a dark brown colour described as the ‘dental star’
What is the function of tertiary dentin?
Tertiary dentin is formed in response to local insults
How is cementum structured within equine dentition?
Cementum covers the crown and fills the infunfibula in equine dentition
What are the four components of the periodontum?
Gingiva
Alveolar bone
Cementum
Periodontal ligament
What are the functions of the periodontum?
Protection of the teeth, nerves and blood vessels
Attachment of teeth to alveolar bone
Transmission of occlusal forces
What is the term used to describe the infundibulum present in the incisors?
Incisal cusp
What are the occlusal differences between maxillary and mandibular cheek teeth?
Maxillary cheek teeth contain infundibula whereas mandibular cheek teeth do not, resulting in a greater infolding of peripheral enamel in mandibular cheek teeth
What is anisognathia?
Anisognathia is where the mandibular teeth are more narrow set than the maxillary teeth in horses
What is the normal angulation between the maxillary and mandibular cheek teeth in horses?
10 - 15°
When do the first deciduous incisors erupt?
6 days old
When do the second deciduous incisors erupt?
6 weeks old
When do the third deciduous incisors erupt?
6 months old
When do the first permanent incisors erupt?
2.5 to 3 years old
When do the second permanent incisors erupt?
3.5 to 4 years old
When do the third permanent incisors erupt?
4.5 to 5 years old
When does the permanent second premolar erupt?
The permanent second premolar erupts at 2.5 years old
When does the permanent third premolar erupt?
The permanent third premolar erupts at 3 years old
When does the permanent fourth premolar erupt?
The permanent fourth premolar erupts at 4 years old
When does the permanent first molar erupt?
The permanent first molar erupts at 1 year old
When does the permanent second molar erupt?
The permanent second molar erupts at 2 years old
When does the permanent third molar erupt?
The permanent third molar erupts at 3.5 years old
Which equine teeth are embedded in the maxillary bone?
The alveoli of 106, 107, 206 and 207 are embedded in the maxillary bone, and commonly the rostral portion of 108 and 208 are also embedded in the maxillary bone
Which equine teeth lie in the rostral maxillary sinus?
The caudal aspect of the alveoli of 108, 109, 208 and 209 usually lie in the rostral maxillary sinus
Which equine teeth lie in the caudal maxillary sinus?
The alveoli of 110, 111, 210 and 211 usually lie in the caudal maxillary sinus
What is the difference between an overbite and an overjet?
Also known as ‘parrot mouth’
When a horse has an overbite, the upper teeth are vertically misaliged and overlap the bottom teeth, whereas with an overjet, the upper teeth are horizontally misaligned
What is the prognosis for an overbite/overjet in horses?
An overjet/overbite does not tend to affect grazing and generally has a good prognosis
When should you treat overbites/overjets?
Horses with overbites/overjets will generally be fine without treatment however if you are going to treat it, it should be treated in young horses. It can be beneficial to treat this as overbites can result in incisor overgrowth and concurrent malocclusion of the cheek teeth
What can be done to treat an overbite/overjet?
Biteplates
Bitewires
What is the main disadvantage of bite plates and bite wires?
Bite plates and bite wires can break and may require repeat general anaesthetics to repair them
Make owners aware of this
Identify this equine dental abnormality
Incisor overgrowth ‘smile mouth’
What can cause incisior overgrowth ‘smile mouth’?
Incisior overgrowth can be caused by uncorrected ‘parrot mouth’
What is a mandibular prognathism (‘sow mouth’)?
Mandibular prognathism (‘sow mouth’) is misalignment of the lower jaw resulting in an malocclusion and an underbite
Identify this equine dental abnormality
Developmental incisor displacement
What are the potential consequences of developmental incisor displacement?
Developmental incisor displacement can cause damage to surrounding soft tissue structures (such as cheeks, lips etc) and result in diastema between the teeth which can accumulate with food and progress to periodontal disease. Because of this, these teeth often require removal
(T/F) You should always immediately remove retained deciduous teeth in horses
FALSE. You should investigate the age of the horse as retained deciduous teeth are normal in horses of a certain age and thus do not require removal
What is a mental nerve block in horses?
A mental nerve block is the infusion of local anaesthesia into the mental foramen
When are mental nerve blocks indicated in horses?
Mental nerve blocks are indicated for extraction of the lower teeth
What is a infraorbital nerve block in horses?
An infraorbital nerve block is the infusion of local anaesthesia into the infraorbital foramen
When are infraorbital nerve blocks indicated in horses?
Infraorbital nerve blocks are indicated for extraction of the upper teeth
When are mandibular nerve blocks indicated?
Mandibular nerve blocks are indicated for caudal lower cheek teeth extractions
When are maxillary nerve blocks indicated?
Maxillary nerve blocks are indicated for caudal upper cheek teeth extractions
Identify this equine dental abnormality
Supernumerary incisors
What should be done before extracting supernumerary incisors?
Dental radiography to see where the roots sit to plan your extractions
What is the prognosis for horses with supernumerary incisors?
Supernumerary incisors tend to have little clinical significance
Which signalement is prone to tooth trauma?
Juvenile horses due to kicks and collisions
What is the difference between uncomplicated and complicated fractures?
Uncomplicated fractures do not involved the dental pulp whereas complicated fractures do involved the dental pulp
When does incisor trauma require treatment in horses?
Incisors involving the pulp cavity - i.e. complicated fractures - require treatment
Do radiographs to determine if there is pulp involvement
What can be done to try and preserve teeth that have suffered complicated fractures in horses?
When a tooth suffers trauma, there will be a lot of inflammation which can cause avascular necrosis of the pulp cavity so you should give anti inflammatory drugs to try and preserve the pulp. There is also risk of infection so you should disinfect and debride the area to preserve the pulp cavity
What is an avulsion fracture?
An avulsion fracture is a fracture involving the surrounding bone structures resulting in the teeth and the bone becoming displaced
How do you treat avulsion fractures?
Wire fixation of the avulsion fracture. Often the teeth will be left in situ even if they’re damaged until the alveolar bone has repaired and then the teeth will be extracted
What is one of the most common causes of abnormal incisor wear?
Crib biting
What is equine odontoclastic tooth resorption and hypercementosis (EOTRH)?
Equine odontoclastic tooth resorption and hypercementosis (EOTRH) results in resorbative lesions of the teeth and excessive sub-gingival cementum deposition
What is the typical signalement for equine odontoclastic tooth resorption and hypercementosis (EOTRH)?
Older horses
What is the carrot test?
The carrot test is a test used to determine if a horse can bite through a carrot to test if they are in pain due to equine odontoclastic tooth resorption and hypercementosis (EOTRH)
How do you treat equine odontoclastic tooth resorption and hypercementosis (EOTRH)?
There is not much treatment available for equine odontoclastic tooth resorption and hypercementosis (EOTRH) other than extracting any loose or painful teeth and treat any secondary apical infections
Identify this equine dental abnormality
Slant/slope mouth
How do you treat slope/slant mouth?
Typically slant/slope mouth does not require treatment
What is wry nose?
Wry nose is a congenital condition in foals where the nose appears twisted or crooked due to gestational malformations
What are the consequences of wry nose?
Wry nose can result in nasal occlusion and incisor malocclusion and abnormal wear. Severe cases of wry nose may require euthanasia
What are the consequences of incisor diastemas?
Incisor diastemas can result in food impaction and gingivitis
How do you treat incisor diastemas?
A toothbrush can be used to remove trapped food and impactions and use hacksaw blades and diamond coated discs to widen the gaps to reduce the risk of impaction
Which canine abnormalities can be seen in horses?
Canine displacement
Incomplete eruption
Calculus
Equine odontoclastic tooth resorption and hypercementosis (EOTRH)
Why do equine canines commonly develop calculus?
Canines commonly develop calculus as they are not used for chewing so the calculus does not get broken off
How do you treat calculus accumulation?
You can use forceps to crack the calculus on the teeth
Which portion of the mouth should you assess if a horse is resisting the bit?
Interdental space
What is the wolf tooth in horses?
A wolf tooth is an underdeveloped first premolar
When do wolf teeth typically erupt?
Wolf teeth typically erupt at one year old
What are the indicators for removing wolf teeth in horses?
Displaced wolf tooth
Fractured wolf tooth
Large wolf tooth
‘Blind’ wolf tooth
Wolf tooth on the lower jaw
What is a ‘blind’ wolf tooth?
A ‘blind’ wolf tooth is a wolf tooth which does not fully erupt from the gums
Why should lower wolf teeth be extracted?
Lower wolf teeth should be extracted as they can cause bitting discomfort
What should you be aware of when carrying out wolf tooth extractions?
When carrying out wolf tooth extractions, be aware that the greater palatine artery runs medially towards the palate, under the gingiva and it is possible to damage the artery
What are retained caps?
Retained caps is the retainment of the remnants of deciduous cheek teeth
What are the potential consequences of retained caps?
Retained caps can result in soft tissue trauma and oral pain in horses
Describe the normal anatomical positioning of the equine cheek teeth and the functional significance of this
Equids have 24 cheek teeth split into four groups of 6 on each side of the upper and lower jaw. These 6 teeth should be closely packed together to act as one grinding unit, with the front and back tooth of each row slightly angled so they keep the teeth positioned tight together
What is equine diastemata?
Equine diastemata is the term used to describe gaps between the cheek teeth
What are the two classifications of equine diastemata?
Open diastema
Valve diastema
What is the difference between open and valve diastema?
Open diastema is where the gap is the same width whereas valve diastema is where the gap is narrower near the occlusal surface and is wider apically
What are the consequences of equine diastemata?
Equine diastemata allows food to become stuck and compressed into the gaps which can result in peridontal disease and oral pain. In severe cases this can result in secondary apical infection which in the maxillary cheek teeth can extend into the maxillary sinuses
Which radiograph view can you use to investigate equine diastemata?
Open mouth dental radiographs
What is one of the key clinical signs of equine diastemata?
Quidding
How can you treat equine diastemata?
Removal of impacted food
Filling the diastemata with impression material
Partial or full widening of the diastemata
Reduce the excessive transverse ridges opposite the diastema
Dietary modification
Which tools can be used to remove impacted food from equine diastemata?
Right-angled diastema forceps
Flushing
How should you prepare for removing impacted food from equine diastemata?
This is a painful procedure so you should sedate the horse, administer local anaesthetic and give anti-inflammatories
What are the risks of diastemata widening procedures?
There is a risk of direct pulp exposure and overheating the teeth with diastemata widening
What dietary modifications are essential for treating equine diastemata?
Eliminate long fibre foods (i.e. hay, haylage, mollichaff) and replace with short fibre foods
List three examples of short fibre foods
Grass
Alfalfa
Cubes
How much can you reduce rostral overgrowths of the cheek teeth per treatment?
You can reduce rostral overgrowths of the cheek teeth 3-4mm per treatment to avoid exposing the dental pulp
Which dental overgrowths are often missed in equine dentals?
Caudal overgrowth of the third molars (11s)
What is the curve of spee?
The curve of speed is the term used to describe the anatomic curvature of the third molars (11s)
How do you differentiate between the curve of spee and an overgrowth?
The curve of spee should be running parallel to the gingiva however if it is not, then it is likely a caudal overgrowth
What is the typical presentation of developmental cheek teeth displacements?
Developmental cheek teeth displacements tend to be severe bilateral buccal or lingual displacements usually affected the 09s and 10s (first and second molars)
What is the typical presentation of acquired cheek teeth displacements?
Acquired cheek teeth displacements tend to be less severe displacements affecting the mandibular 10s and 11s (second and third molars) as a result of disease
What are the consequences of cheek teeth displacements?
Cheek teeth displacements can result in malocclusion and uneven wear, diastemata which can result in feed accumulation and periodontal disease, damage to surrounding soft tissue structures and oral pain
How do you treat cheek teeth displacement?
To treat cheek teeth displacement, treat the periodontal disease and rasp down any overgrowths every 6 months
When do displaced cheek teeth require extraction?
Displaced cheek teeth require extraction if there are more than 50% out of alignment from the other cheek teeth or if there is severe periodontal disease, especially in older horses
What are connated cheek teeth?
Connated cheek teeth is a term used to describe fused teeth
What are the consequences of supernumerary cheek teeth?
Supernumerary cheek teeth result in malocculsion, overgrowth and periodontal disease
How do you treat supernumerary cheek teeth?
To treat supernumerary cheek teeth, treat the periodontal disease, rasp down any overgrowths every 6 months
When do supernumerary cheek teeth require extraction?
Supernumerary cheek teeth require extraction if there is severe periodontal disease
What is oligodontia?
Oligodontia is the developmental absence of the normal number of teeth
(T/F) Oligodontia is very common
FALSE. True olidgodontia is very rare
What is stepmouth?
Stepmouth is a form of malocclusion where one of the cheek teeth is longer than the others
What is wavemouth?
Wavemouth is a form of malocclusion where the entire grinding surface rises and falls in a wave-like pattern
How does feeding concentrates affect the wearing of the cheek teeth in horses?
Feeding concentrates reduces the lateral masticatory jaw movements, altering the wear patterns of the cheek teeth which can result in the development of sharp enamel points
Where do sharp enamel points typically develop on the maxillary cheek teeth?
Sharp enamel points typically develop on the buccal surface of the maxillary cheek teeth
Where do sharp enamel points typically develop on the mandibular cheek teeth?
Sharp enamel points typically develop on the lingual surface of the mandibular cheek teeth
What are the consequences of sharp enamel points on the cheek teeth?
Sharp enamel points on the cheek teeth can cause both cheek and tongue ulceration
How do you treat sharp enamel points?
Rasp the sharp enamel points (be aware to only rasp the points and not the occlusal surface of the tooth which should remain irregular to allow horses to break up their feed)
When do cheek teeth fractures require treatment?
Complicated fractures (dental pulp involvement) require treatment
What are the potential complications of cheek teeth lateral slab fractures?
With cheek teeth lateral slab fractures, the slab of tooth can be diverted and cause trauma to the surrounding soft tissue. Can also result in infection of the pulp cavity or apical infection
What is infundibular cemental hypoplasia?
Infundibular cemental hypoplasia is the developmental failure of complete cemental filling of the infundibula
What are dental caries?
Dental caries is dental decay which occurs in horses due to the breakdown of the teeth due to the action of bacteria which ferment and produce acids, often as a result of the horse’s diet
How does infundibular cement hyoplasia predispose horses to caries
Infundibular cement hypoplasia predisposes the infundibula to become filled with feed material and the bacteria can ferment and product acid which can result in midline sagittal fracturing of the teeth as the affected teeth continue to erupt, known as dental caries
What is grade 1 dental caries?
Grade 1 is where the caries only affects the cementum
What is grade 2 caries?
Grade 2 is where the caries affects the cementum and underlying enamel
What is grade 3 caries?
Grade 3 is where the caries affects the cementum, enamel and dentine
What is grade 4 caries?
Grade 4 is where the tooth integrity is affected (i.e. there has been a secondary dental fracture)
Which oral tumours are more commonly seen in young horses?
Fibro-osseous tumours of the rostral mandible
What is a key clinical sign of an apical infection of mandibular cheek teeth?
An apical infection of the mandibular cheek teeth can result in swelling at the jaw
What is a key clinical sign of an apical infection of rostral maxillary cheek teeth?
An apical infection of the rostral maxillary cheek teeth can result in swelling
What is a key clinical sign of an apical infection of caudal maxillary cheek teeth?
An apical infection of the caudal maxillary cheek teeth will have no swellings however there will be nasal discharge due to secondary sinus infection
How do you treat apical infections?
Apical infections are very challenging to treat and usually require tooth extraction
Which imaging modality is useful for assessing apical infections?
CT
What abnormality can be detected in this latero-lateral radiograph?
Fluid line in the maxillary sinuses
What is indicated by a fluid line on radiography?
A fluid line is indicative of paranasal sinusitis
What is one of the key signs of paranasal sinusitis?
Unilateral nasal discharge
Paranasal sinusitis is the most common cause of this in horses
What is important to determine when investigating paranasal sinusitis?
If you suspect paranasal sinusitis, it is important to determine whether it is primary or secondary as this will dictate future treatment of the patient
What is the most common cause of secondary paranasal sinusitis?
Apical infection of the caudal maxillary cheek teeth
How do you treat paranasal sinusitis secondary to apical infection of the cheek teeth?
Treatment consists of a combination of tooth extraction, lavage of the paranasal sinuses and administration of systemic antibiotics
What are the four cheek tooth extraction techniques?
Oral extraction
Minimally invasive transbuccal extraction (MTE)
Tooth sectioning and retrieval
Repulsion
What is the preferred method of cheek tooth extraction?
Oral extraction
Which extraction technique should be used if oral extraction is not possible?
Minimally invasive transbuccal extraction (MTE)
What are some of the complications of tooth repulsion?
Make a hole in the upper and lower jaw and insert a pin through the alveolar bone and hit it with a mallet to push out the tooth
Chronic sinusitis
Oronasal fistulas
Sequestration of alveolar bone
Persistent tooth fragments
