Lecture 33 - Mammalian teeth Flashcards
What does a higher metabolic rate allow for?
Higher rate of sustained activity
What are the advantages of endothermy?
Exploit wider range of thermal environments
Mammals can have a higher basal metabolic rate
What is thecodonty?
Mammal’s teeth are anchored within bony sockets of the jaw
What is diphyodonty?
Mammals have two different sets of dentition
What are the two sets of dentition?
Milk drinking
– and –
Permanent
What is heterodonty?
Mammals have different teeth in different parts of the mouth that have different functions
What direction is mesial?
Towards anterior portion of the mouth
What is distal?
Towards posterior portion of the mouth
What is lingual?
Towards the tongue
What is buccal?
Towards the cheek
What is labial?
Towards the lips
What are the two regions of the tooth?
Crown and root
What covers the crown?
Enamel
What covers the root?
Cementum
What makes up most of the tooth?
Detine
What is within pulp?
Nerves and blood vessels
What do the nerves and vessels enter the tooth through?
Apical foramen
What is the boney socket in which the tooth is called?
Alveolus
What holds in the tooth?
Periodontal ligament
What are the four types of mammalian teeth?
Incisors - Canines - Premolars - Molars
What are molars for?
Fracturing
What are premolars for?
Fracturing
What are canines for?
Gripping
What are incisors used for?
Gripping and cracking
What is the dental formula for marsupials (metatherians)?
I5-C1-P3-M4
I4-C1-P3-M$
What is the dental formula for eutherians (placental mammals)?
I3-C1-P3-M4
same
What is the dental formula for dogs?
I3-C1-P4-M2
I3-C1-P4-M3
What is the dental formula for cats?
I3-C1-P3-M1
I3-C1-P2-M1
What are pigs dental formula?
Same as eutherians
What is polyphyodonty?
Teeth are constantly replaced
Where is the primordium of the permanent tooth located in relation to the deciduous tooth?
Lingual side
What part of the permanent tooth forms first?
Crown
What happens before the permanent tooth can push out the deciduous?
Root of the deciduous is resorbed
What pushes the permanent tooth up?
Formation of the root
What is different about the formation of molars?
Only have permanent?
Why is grip important?
Grasping food item and transferring to mouth
Why do animals chew?
To fracture food
What does soft food require from teeth?
Long slices
What does tough shelled with soft contents require from teeth?
Puncturing and/or cracking of shell with little processing after
What does softer shell with inner contents that require processing need from teeth?
Puncturing and/or cracking of shell with crushing/grinding of inner contents
What does tough fibrous materials need for processing?
Large amount of grinding and maceration to break down cellulose
What is imprecise occlusion?
Cusps of contact surface cheek teeth do not occlude accurately with each other
What is precise occlusion?
Cheek teeth occlude precisely with each other in a proscribed manner that is associated directly with food processing
What is different about carnivora teeth?
Upper teeth bite on buccal side of lower ones in shearing motion
Preludes lateral movement of the jaw
No grinding
What are large incisors and canines for in carnivora?
For capturing prey and removing large chunks
What are carnassial teeth?
Upper P4 and lower M1
What are carnassial teeth used for?
Form two long blades that act like scissors to slice meat
What is another name for carnassial teeth?
Sectorial teeth
What are bunodont teeth?
Teeth that have low-rounded cusps
What animals have bunodont teeth?
Gorilla and wild boar
What happens as animal ages with bunodont teeth?
Create dentine pits or bowls which opposing cusps fit
What has occurred with swine canines?
Have become tusks
What is the function of tusks?
Fighting
When do canines stop growing in sows?
2 years
What are two adaptations of a herbivore diet?
Browsing and Grazing
What is a browsing diet?
Woody dicot plants
What is a grazing diet?
Primarily monocot plants
What are lophodont teeth?
Teeth with ridges connecting molar cusps
What are loxodont teeth?
Extreme lophodonty
What animals have lophodont teeth?
Chinchillam Taprius
What animals have loxodont teeth?
Mammoths and elephants
Some rodents
What are selenodont teeth?
Teeth with long mesio-distal crescent
What animal have selenodont teeth?
American bison
What is brachydonty?
Low-crowned teeth
With longer roots
What is hypsodonty?
High-crowned teeth with long crowns and short roots
What is high amount of hypsodonty related to?
Exogenous grit in diet
What is lacking in ruminants?
Upper incisors and canine
What is lower canine called in ruminants?
Fourth incisor
What is a diastema?
Space between anterior and cheek teeth
What is the adaptation of the dental pad in browsers?
Narrower - allows for finer control of what food parts are consumed
What is the adaptation of the dental pad in grazers?
Wide dental pad - Allows for cropping of more grass with each bite
What is the structure of the decidous incisors of a newborn calf?
Enamel still surrounds the crown
What happens to the teeth of a two year old ruminant?
I1 has been replaced
Distal border of I1 is slightly word, dentine is exposed
What is the characteristics of tooth wear in a three and a half year old calf?
I1, 2, and 3 are permanent
I4 still deciduous
Occlusal surface of I2 - wider than I 3
What is the characteristics of tooth wear in a eight year old ruminant?
Lingual edge of occlusal surgace of I1 and 2 is smooth
What are the characteristics of the cheek teeth in ruminants?
Selenodont
Hypsodont
Increase in size distally
What are the characteristics of a grazer’s incisors?
Hypsodont
Roots converge so upper and dental arcades form wide grasping surface
What are the characteristics of canines in grazers?
usual only males
Large roots into maxillary sinus
Small crowns
What are the characteristics of cheek teeth?
Selenodont
Complex enamel folding - florets
What is a wolf tooth?
Upper P1 - often fails to develope
What are dental caries?
Cavity formed in the enamel and dentine of the tooth
