Dentition 2 - Large Animal was

Question 1

Horses are radicular hypsodonts. What does this mean?

Answer 1

They have true roots

They have long crown

Question 2

What type of teeth do ruminants have for their premolars and molars, and their incisors and canines?

Answer 2

Radicular hypsodonts - true roots, long crown

Brachydont incisors and canines - short crown, longer wide root

Question 3

How many deciduous teeth do horses have? When do these erupt?

Answer 3

24

6 weeks except incisor 3 (I3)

Question 4

How many adult teeth do horses have? When do these erupt by?

Answer 4

36-44 (variable canines and premolars)

4.5 years, except canines - 6 years

Question 5

What is the wolf tooth?

Answer 5

Small, first premolar. Not always found

P1

Question 6

Why are horse teeth rigid?

Answer 6

Different hardness of cementum, dentine and enamel. Wear at different rates.
Cementum initially covers crown

Question 7

What is the gap between the canines and premolars called?

Answer 7

Diastema

Bar

Question 8

As the teeth wear down, the dental star becomes visible. What is the dental star?

Answer 8

Where the pulp cavity has filled with secondary dentine and darkened

Question 9

What is the name of the ‘cup’ of the horse tooth, which is a hole which fills with compact food?

Answer 9

Infundibulum

Question 10

How does the cross-sectional shape of a horse tooth change over their life?

Answer 10

Oval -> circular -> triangular

Question 11

In older horses, a white spot can be visible in the dental star. What is this?

Answer 11

Tertiary dentine

Question 12

The incisor hook can be used to age a horse, however it is unreliable. What is the incisor hook? What ages is this present?

Answer 12

Hook on I3 due to incomplete occlusion

5-7, 11-13

Question 13

The Galvayne’s Groove is another unreliable way to age horses. What is this? What ages is it present?

Answer 13

Yellow groove down I3.

Starts at age 10, half way down tooth at 15, fully down at 20

Question 14

As teeth age, which way do they point?

Answer 14

Rostrally

Question 15

Which teeth are classed as horse teeth cheek?

Answer 15

Premolars and molars except wolf (PM1)

Question 16

As horse cheek teeth age, what is different about their pulp cavities?

Answer 16

They seperate into up to 8 chambers

Question 17

What shape are the horse cheek teeth?

Answer 17

Rectangular

Except M3 is triangular

Question 18

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?

Answer 18

Diastemata

Question 19

Describe the shape of the upper and lower cheek teeth of a horse

Answer 19

Upper cheek teeth are wider and curved
Lower cheek teeth are straight
Both rows curve at caudal end - Curve of Spee

Question 20

For normal horse occlusion, what proportion of teeth should be in contact?

Answer 20

1/3

Question 21

In the upper and lower cheek teeth, how many infundibulas should be visible on the occlusal surface?

Answer 21

Upper - 2

Lower cheek - none, infoldings of enamel

Question 22

What happens to the cheek teeth and maxillary sinus as a horse ages?

Answer 22

Overlap changes, sinus can be used to access roots at older age

Question 23

What are 3 methods for tooth extraction?

Answer 23

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

Question 24

Which structures do you need to avoid during tooth extraction of a horse?

Answer 24

Infraorbital nerve
Dorsal/ventral buccal nerves
Parotid duct (saliva)

Question 25

On radiographs, around each tooth a thin white and black line can be seen. What are these lines?

Answer 25

Thin white line = thin alveolar bone - Lamina dura

Thin black line - periodontal ligament

Question 26

How many deciduous and adult teeth do cattle and sheep have?

Answer 26

20 deciduous

32 adult

Question 27

Cattle and sheep do not have front upper teeth (incisors and canines). What do they have instead?

Answer 27

Dental pad

Question 28

Why are the deciduous premolars of cattle/sheep larger than the adult ones?

Answer 28

The deciduous are unsupported by molars and need to do more grinding

Question 29

At what age do cattle deciduous teeth and adult teeth erupt?

Answer 29

3 weeks

3.5 years old

Question 30

At what age do sheep deciduous and adult teeth erupt?

Answer 30

4 weeks

2.5 years (except canines - 4 years)