Comparative dentition Flashcards
What is the deciduous dental forumla for Cow?
I 0/4 C 0/0 PM 3/3
(x2) = 20
What is the permanent dental forumla for Cow?
I 0/4 C 0/0 PM 3/3 M 3/3
(x2) = 32
What is the deciduous dental forumla for Sheep?
I 0/4 C 0/0 PM 3/3
(x2) = 20
What is the permanent dental forumla for Sheep?
I 0/4 C 0/0 PM 3/3 M 3/3
(x2) = 32
What is the deciduous dental forumla for Pigs?
I 3/3 C 1/1 PM 4/4
(x2) = 32
What is the permanent dental forumla for Pigs?
I 3/3 C 1/1 PM 4/4 M 3/3
(x2) = 44
What is the foals’s dental forumla for Horse?
I 3/3 C 0/0 PM 3/3
(x2) = 24
What is the Mature male’s dental forumla for Horse?
I 3/3 C 1/1 PM 3(or 4)/3 M 3/3
(x2) = 40 (- 42)
WT = Wolf Tooth
What is the Mature female’s dental forumla for Horse?
I 3/3 C 0/0 PM 3(or 4)/ 3 M 3/3
(x2) = 36 - 40
What is a dental arcade?
A series or arches + how the teeth are arranged within the oral cavity
How many dental archades are there in the oral caivity?
2
Name the 2 bones that are associated with the 2 dental arcades?
- Top arcade = Maxilla
- Bottom arcade = Mandible
What is meant by the term Diastema
A gap in the teeth between the incisors + cheek teeth
What are Hypsodont teeth?
Teeth with:
* Deep roots
* Tall crowns
* No discernable neck
* Straight sides
What are Brachydont teeth?
Teeth with:
- Short roots
- Short crowns
- Discernable neck
- Curved edges
What are Heterodont teeth?
Hetero = different
Vairous different types of teeth that have specialised functions
(I, C, PM, M)
“Di-phyo-dont” = ‘DIffyodont’
What are Diphyodont teeth?
Di = 2
Describes teeth that go through 2 cycles - deciduous + permanent
Think D for Deciduous
How does poor molar health impact a Ewe?
It is detrimental for both lamb + ewe, as they cannot maintain their nutritional health, energy or milk for the lamb
What percentage of male horses have wolf teeth?
+
What percentage of female horses wolf havve teeth?
- Male horses = 15%
- Female horses = 25%
Where are the Incisors located?
+
What is their function?
Located = Front of the mouth
+
Function:
* Biting
* Cutting
* Fine nibbling
* Grooming
Where are the Canines located?
+
What is their function?
Located = Between the incisors + premolars
+
Function:
* Grip prey
* Tusks in Pigs
* In male Horses
Note =
* Not present in all species
* In carnivores
Where are the Premolars located?
+
What is their function?
Located = Between the canines + molars
+
Function:
* Known as ‘Cheek’ teeth
* Grinding food
Where are the Molars located?
+
What is their function?
Located = Back of the mouth + after the premolars
+
Function:
* Grinding food
* Not present in deciduous teeth
What is the function of the wolf teeth in horses?
- No known function!
- Vestigal teeth
Why are wolf teeth sometimes removed in horses?
- Because they can interfere with the bit
- Can cut the mouth’s soft tissues, needing filed down
How many hours a day do horses typically graze for?
18 hrs
True or False.
Cheek teeth, otherwise known as premolars, slowly erupt throughout the horses life.
True
True or False.
Almost the entire hypsodont tooth is covered in rigid enamel.
True!
What can wear patterns + tooth shape tell you about the horse?
Their age
When do wolf teeth develop in the horse?
From: 18 months > 5 years
At what age do cows 1st Incisor erupt?
18 - 24 months
At what age do cows 2nd Incisor erupt?
24 - 30 months
At what age do cows 3rd Incisor erupt?
36 months
At what age do cows 4th Incisor erupt?
24 - 48 months
Do cows have upper incisors?
No
What replaces a cow’s deciduous incisors?
A Hard pad of tissue, known as a dental pad
True or False.
The cow’s **deciduous lower canines **develop into 9 lower incisors.
False, they develop into 8!
What type of incisors do cows have?
Brachydont
Do cows have canines?
No
Do cows cut or break grass?
Break!
How do cows chew their herbivorous diet?
From chewing from side to side (vertically)
How many hours do cows graze for?
8 - 10 hrs
How many hours do cows ruminate for?
8 - 10 hrs
True or False.
The canine teeth usually appear only in male horses; the canine teeth are usually regressed or absent in mares.
True!
What type of teeth are the wolf teeth?
Small premolars
True or False.
The wolf teeth is most commonly seen in the upper jaw, sometimes in the lower jaw + can be unilateral or bilateral.
True!
How many mm does the occulusal surfaces wear down per year, by mastication, in the Horse?
2 - 3 mm
True or False.
All teeth grow continually in the horse.
True
What term is used to describe the horses teeth?
Hypsodontal
What does Hypsodontal mean?
They do not have a layer of enamel over the top or occlusal surface
What is the occlusal surface of the tooth?
The surface of the tooth that is used for chewing or grinding
What happens to hypsodontal teeth over time?
- The enamel + softer dentine provide a effcient grinding surface that wears down with age + use
What are the 3 signs of age + use in hypsodontal teeth, in Horses?
- Marks
- Stars
- Grooves
How can you tell the age of the horse?
By the quality of their teeth, due to the marks, stars + grooves of the hypsodontal teeth
What 2 types of teeth does ‘cheek teeth’ refer to in the horse?
- Premolars
- Molars
How many premolars + molars are there in the horse, in each jaw ?
6 premolars + 6 molars
At what age do wolf teeth develop in the horse?
Between:
18 months > 5 years old
Which of the following animals have Hypsodont teeth?
A. Cow
B. Sheep
C. Horse
D. Pig
A. Cow
B. Sheep
C. Horse
Which of the following animals have Brachydont teeth?
A. Cow
B. Sheep
C. Horse
D. Pig
D. Pig
Which of the following animals have both Brachydont + Hypsodont teeth and why?
A. Cow
B. Sheep
C. Horse
D. Pig
C. Horse
D. Pig
+
* The Horse has canine teeth, the wolf teeth and they are brachydont, whereas the rest are hypsodont
* The Pig has canine teeth, the tusks and they are brachydont, whereas the rest are hypsodont
