Dentition 2 - Large Animal was Flashcards
Horses are radicular hypsodonts. What does this mean?
They have true roots
They have long crown
What type of teeth do ruminants have for their premolars and molars, and their incisors and canines?
Radicular hypsodonts - true roots, long crown
Brachydont incisors and canines - short crown, longer wide root
How many deciduous teeth do horses have? When do these erupt?
24
6 weeks except incisor 3 (I3)
How many adult teeth do horses have? When do these erupt by?
36-44 (variable canines and premolars)
4.5 years, except canines - 6 years
What is the wolf tooth?
Small, first premolar. Not always found
P1
Why are horse teeth rigid?
Different hardness of cementum, dentine and enamel. Wear at different rates.
Cementum initially covers crown
What is the gap between the canines and premolars called?
Diastema
Bar
As the teeth wear down, the dental star becomes visible. What is the dental star?
Where the pulp cavity has filled with secondary dentine and darkened
What is the name of the ‘cup’ of the horse tooth, which is a hole which fills with compact food?
Infundibulum
How does the cross-sectional shape of a horse tooth change over their life?
Oval -> circular -> triangular
In older horses, a white spot can be visible in the dental star. What is this?
Tertiary dentine
The incisor hook can be used to age a horse, however it is unreliable. What is the incisor hook? What ages is this present?
Hook on I3 due to incomplete occlusion
5-7, 11-13
The Galvayne’s Groove is another unreliable way to age horses. What is this? What ages is it present?
Yellow groove down I3.
Starts at age 10, half way down tooth at 15, fully down at 20
As teeth age, which way do they point?
Rostrally
Which teeth are classed as horse teeth cheek?
Premolars and molars except wolf (PM1)
As horse cheek teeth age, what is different about their pulp cavities?
They seperate into up to 8 chambers
What shape are the horse cheek teeth?
Rectangular
Except M3 is triangular
In horse cheek teeth there should be no gaps as they work as one functional unit. If there is a gap this can cause issues. What is this gap called?
Diastemata
Describe the shape of the upper and lower cheek teeth of a horse
Upper cheek teeth are wider and curved
Lower cheek teeth are straight
Both rows curve at caudal end - Curve of Spee
For normal horse occlusion, what proportion of teeth should be in contact?
1/3
In the upper and lower cheek teeth, how many infundibulas should be visible on the occlusal surface?
Upper - 2
Lower cheek - none, infoldings of enamel
What happens to the cheek teeth and maxillary sinus as a horse ages?
Overlap changes, sinus can be used to access roots at older age
What are 3 methods for tooth extraction?
Per os - through mouth (front teeth only)
Buccotomy - through cheek, remove overlying bone (premolars)
By repulsion - via skull/maxillary sinus (molars). Invasive - uses metal punch and hammer
Which structures do you need to avoid during tooth extraction of a horse?
Infraorbital nerve
Dorsal/ventral buccal nerves
Parotid duct (saliva)
On radiographs, around each tooth a thin white and black line can be seen. What are these lines?
Thin white line = thin alveolar bone - Lamina dura
Thin black line - periodontal ligament
How many deciduous and adult teeth do cattle and sheep have?
20 deciduous
32 adult
Cattle and sheep do not have front upper teeth (incisors and canines). What do they have instead?
Dental pad
Why are the deciduous premolars of cattle/sheep larger than the adult ones?
The deciduous are unsupported by molars and need to do more grinding
At what age do cattle deciduous teeth and adult teeth erupt?
3 weeks
3.5 years old
At what age do sheep deciduous and adult teeth erupt?
4 weeks
2.5 years (except canines - 4 years)
