Teeth & Mastication Flashcards
What’s Cementum?
‘Glue’ that links root dentine and periodontal ligament
Mouth anatomical directions?
2 Things that happen to grow tooth?
Enamel knot
Dentine forming cells?
Odontoblasts
Enamel forming cells?
Ameloblasts
What’s Dentine made of?
Weave of collagen, ground substances and hydroxyapatite
70% Mineral
What does an odontoblast secrete?
A single dentine tubule
How is enamel made?
1) Ameloblasts secrete enamel matrix (mostly proteins/minerals)
2) Mineralization: Hydroxyapatite crystals grow & encompass matrix
96% Mineral
Each ameloblast creates a single enamel prism
How does Circadian Rhythm affect enamel?
Secretion pauses every day, creates lines and striations that can help determine how long it took animal to grow the tooth
(longer time often = larger brain)
Homodonty?
Having only 1 type of tooth (fish & early tetrapods)
Single-cusped teeth
Good at catching prey, but not for chewing
Heterodonty
Mammals
incisors
‣ canines
‣ premolars
‣ molars
Evolution of multicusped teeth?
Tribosphenic Molar
What is each human tooth specifically called?
Properties of incisors
Single, blade-like cusp
Single root
Properties of canines
Single, pointed cusp
Single root
Properties of premolars
2 cusps
Single root
Properties of molars
4-5 cusps
2 or 3 roots
What are postcanines good for in different animals?
Humans/apes: Grinding brittle foods
Cats, etc: Shearing/cutting ductile foods
Diphyodonty
Having deciduous teeth before permanent teeth
Odontoclasts
Absorb roots of deciduous teeth
TMJ movements
elevation/depression
protraction/retraction
medial-lateral shift (“Bennett shift”)
Masticatory Muscles & innervation
Medial-Lateral Movement
Requires the activation of the masseter on one side and the medial pterygoid on the other
