Lecture 36: Mammalian Dental Anatomy Flashcards
What is the relationship between mammalian teeth and endothermy
Mammalian teeth permit mammals to process a very diverse array of foods and to do so efficiently, this is critical for maintaining large supply to energy to counter high energy requirements of endothermy
Mesial
Towards anterior portion of mouth
Distal
Towards posterior portion of mouth
lingual
Towards tongue
Palatal
Towards palate
Buccal
Towards check
Labial
Towards lips
What are the three specializations of mammalian teeth
Thecodonty, heterodonty, diphyodonty
What is thecodonty
Teeth are anchored within bony sockets of the jaws (maxillary, pre maxilla, mandible)
What is heterodonty
Differentiation of teeth in different parts of the mouth into distinct functional units
What is diphyodonty
Two different sets of dentition (milk and permanent)
What is the crown part of mammal tooth
Extends from gum line into oral cavity- usually covered by enamel
What is the root part of the mammal tooth
Extends from gum line into the alveolus, coated with cementum
What are the crown and root primarily made of
Dentine
What is the pulp cavity
Hollow cavity filled with pulp
What does pulp of the tooth contain.
Soft tissue that contain nerves and blood vessels of tooth
What anchors teeth within alveolus
Periodontal ligaments
What kind of receptors do periodontal ligaments contain
Stretch receptors important for chewing
What are the steps of diphyodonty- process of tooth replacement
- Periodic thickening of dental lamina, ectoderm inside labiogingival will produce dental buds which give rise to individual teeth.
- If bud is destined for deciduous tooth an additional bud for permanent tooth develops
- As deciduous tooth erupts the primordium of the permanent tooth is already located on lingual side of deciduous tooth
- Crown of permanent tooth is forming and resorption for the root of deciduous tooth occurs
- Permanent tooth ready to breakthrough and deciduous tooth fully reabsorbed
- Permanent molar erupts pushing deciduous out of alveolus
When does eruption of temporary incisors 1-3 occur in dogs
4-6 weeks
When does the eruption of permanent incisors 1-3 occur in dogs
Incisors 1+2: 3-5 months
Incisor3: 4-5 months
When does eruption of temporary canine occur in dogs
3-5 weeks
When does eruption of permanent canine occur
5-7 months
When does eruption of permanent premolar 1 occur in dogs
4-5 months
When does eruption of temporary premolar 2-4 occur in dogs
5-6 weeks
When does eruption of permanent premolars 2-4 occur in dogs
Premolars 2+3: 5-6 months
Premolar 4: 4-5 months
When does permanent eruption of molars 1-3 occur in dogs
Molars 1+2: 5-6 months
Molars 3: 6-7 months
When does the eruption of temporary of feline incisors 1-3 occur
3-4 weeks
When does the permanent eruption of feline incisors 1-3 occur
3.5-5.5 months
When does the temporary eruption of temporary canines in felines occur
3-4 weeks
When does the permanent eruption of canines in felines occur
5.5-6.5 months
When does the temporary eruption of premolars 2-4 occur in felines
5-6 weeks
When does the permanent eruption of premolars 2-4 occur in felines
4-5 months
When does the permanent eruption of molar 1 occur in kittens
5-6 months
What are the four basic tooth types of mammals
Incisors, canines, premolars, and molars
Where are incisors and what are they used for
Anterior dentition and usually used for gripping but also initiating cracks
Where are premolars and what are they used for
Cheek teeth usually used for fracturing
Where are molars and what are they used for
Cheek teeth, usually used for fracturing
What are some advantages of mammalian heterodonty
Increased efficiency and specialization
Do mammals have precise of imprecise occlusion
Precise
What are the three different crown shapes
Bruno don’t, lophodont, Selendont
Bunodont teeth
Rounded cusps
Lophodont teeth
Cusps connected by ridges, ridges can run either bucco-lingual or mesic-dorsally
Selendont teeth
Molar cusps elongate to form ridges
Long mesio-distal crescent shaped molar cusps
Brachydonty
Low crowned teeth, usually with longer roots
Hypsodonty
High crowned teeth, usually with long crowns
What does cementum cover in brachydont vs hypsodont teeth
Cementum only covers root in brachydont teeth but in hypsodont teeth cementum is surrounding enamel
Why is root formation delayed in hypsodont mammals
So that crown continues to grow out of alveolus and can increase amount of exogenous grit in diet
What is the primitive dental formula for mammals
3-1-4-3
What are the 1st, 2nd, and 3rd numbers in triadan numbering system
1st- quadrant
2nd and 3rd- describe the position in the mouth, always begin with central incisor and progress medial to distal
Incisors are always what numbers
01, 02, 03
Canines are always what number
04
Premolars are always what numbers
05, 08
First molar is always what number
09
What are food specialists
Adapted to rely on very limited range of foods
What are food generalists
Adapted to rely on wide range of foods
What teeth are important for capturing and gripping prey
Large caniniform incisors and very large canines
What teeth are responsible for shearing motion in carnivores
Carnassial teeth- upper P4 and lower m1 are enlarged
Do carnivores gain or lose molars as an adaption for processing meat
Loss/reduction of molars
What are the swine adaptions for an omnivorous diet (what crown shape)
Bunodont teeth and the wear of teeth creates pits/bowls which opposing cusps fit
What must herbivores rely on to breakdown structural carbohydrates forming plant cell walls
Symbiotic microbes that ferment carbohydrates in herbivore food into energy rich byproducts- volatile fatty acids
What is the primary energy source in herbivores
Volatile fatty acids
What are the characteristics in a browsing diet
Less homogenous, increased chemical defense, reduced protein digestibility, less exogenous grit diet
What are the characteristics of a grazing diet
Relatively homogenous, less chemical defense, increased protein digestibility, more exogenous grit in diet
What are some adaptions for grazing and browsing in cows
Lack upper incisors and canines, lower canines have a very incisor like shape (4th incisor-I4), large space between anterior and cheek teeth
Do goats/browers have a wide or narrow dental pad and what does it allow for
Narrower dental pad that allows for finer control of what food is being consumed
Do cows/grazers have a narrow or wide dental pad and what does it allow for
Wide dental pad that allows for cropping of more grass with each bite
What crown shape do ruminant cheek teeth have
Selendont and hypsodont
Cheek teeth ___ in size distally
Increase
Upper cheek teeth are ___ than lower ones
Wider
At what age does enamel still surround the crown in cows
Newborn calf
At what age in cows has incisor 1 been replaced, but others haven’t and the distal border of I1 has been slightly worn down with dentine exposed
2 years
At what age in cows are I1-3 present I4 still deciduous
3.5 years
At what age in cows are the lingual edges of occlusal surface of I1 and I2 smooth- teeth are level
8 years
What crown type are horse incisors
Hypsodont
Pattern of incisor wear is very important for ____ in horses
Estimating age
What crown type are cheek teeth in horses
Selendont
Where do dental cavities form
Enamel and dentine of tooth
What species are dental cavities most common
Horses, often extracted
Where can you gain access to maxillary teeth in horse for extraction
Via maxillary sinus
What is gum disease
Bacterial infection of gum surrounding the tooth, leading to placque accumulation
Gingivitis
Only gingiva but no damage to ligaments and bone
Periodontitis
Tissue damage includes ligaments and bones
When do temporary incisors 1-3 erupt in cattle
Birth-2 weeks
When does permanent incisor 1 in cattle
18-24 months
When does permanent incisor 2 erupt in cattle
24-30 months
When does permanent incisor 3 erupt in cattle
36-42 months
When does temporary incisor 4/canine erupt in cattle
Birth- 2 weeks
When does permanent incisor/canine erupt in cattle
42-48 months
When do temporary premolars 2-4 erupt in cattle
Birth-1 week
When does permanent premolar 2 erupt in cattle
24-30 months
When does permanent premolar 3 erupt in cattle
18-30 months
When does permanent premolar 4 erupt in cattle
20-36 months
When does molar 1 erupt in cattle
6 months
When does molar 2 erupt in cattle
12-18 months
When does molar 3 erupt in cattle
24-30 months
When does temporary incisor 1 erupt in horses
6 days
When does temporary incisor 2 erupt in horses
6 weeks
When does temporary incisor 3 erupt in horses
6 months
When does temporary incisor 3 become in wear in horses
1yr
When do temporary incisors 1+2 level out in horses
2yrs
When does permanent incisor 1 erupt in horses
2.5 years
When does permanent incisor 3 erupt in horses
3.5 years
When does permanent incisor 3 erupt in horse
4.5 years
When are all cusps present in horses
5yrs
When is incisor 1 cup gone in horse
6yrs
When is incisor cup 2 gone in horses
7yrs
When is incisor cup 3 gone in horses
8yrs
At what age does galvayne’s groove appear in horses
10 yrs