DENTISTRY - Equine Dentistry Flashcards
How many permanent teeth do horses have?
Horses have between 36 and 44 permanent teeth
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 tje 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?
Within 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 incisions where the teeth encounter high mechanical stress
How is dentin structured within equine dentition?
Dentin is interspersed between enamel, creating a 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 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 second premolar erupt?
The permanent second premolar erupts at 2.5 years old
When does the permanent third premolar erupt?
The permanent second premolar erupts at 3 years old
When does the permanent third molar erupt?
The permanent third molar erupts at 3.5 years old
When does the permanent fourth premolar erupt?
The permanent fourth premolar erupts at 4 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?
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
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
Identify this equine dental abnormality
Incisor overgrowth ‘smile mouth’
What is a mandibular prognathism?
Mandibular prognathism is misalignment of the lower jaw resulting in an underbite