Teeth Lecture Flashcards
Types of teeth (2)
Brachydont
- Low crown
- No growth after eruption through gingva (gum)
- Humans
Hypsodont
- High crown
- Continued growth after eruption through gingiva
- Horses
Brachydont-Crown (anatomical and clinical)
Anatomical: Covered by enamel
Clincal: Visible portion of tooth above gum line
Brachydont-Root
- What
- Covered by
- Purpose
- Where
Attached portion of tooth that extends from anatomical crown
Covered by cementum
Anchors tooth to mandible and maxilla via periodontal ligament
Alveolus
Brachydont-neck
- What
- Purpose
Jxn of anatomical crown and root where enamel ends and cementum begins
Attachment site of gingival epithelium to tooth
Enamel
- What is it
- What is it made of
- What is it NOT made of
It’s the outer covering of crown
Made of 99% calcium phosphate in form of hydroxyapatite crystals
–>Crystals form enamel rods that span enamel
Made of 4% water and enamelin/amelogenin
–>Secreted by ameloblast
NO COLLAGEN PRESENT
Dentin
- what does it do
- Appearance
- What is it made of
- Secreted by
- Dentinal tubules
Forms internal template of tooth
Yellow
70% calcium hydroxyapatite
20% organic
10% water
Secreted by odontoblasts (line surface of pulp cavity)
Dentinal tubules builds thickness of tooth in open channels
What are in patent channels that extend in the entire thickness of dentin?
Dentinal tubules
What do dentinal tubules contain
Odontoblast, tissue fluid, nerve endings
Toughest structure in body
-Second strongest
Enamel
2nd=dentin
Cementum
- What does it do
- Is it cellular or acellular
- What is it made of
Anchors periodontal ligament to root of tooth and coats outer surface of root
Cellular (cementocytes) and acellular
Made of 50% organic (type I collagen) and water
What makes cementum? Maintains?
Cementoblasts make cementum
Cementocytes maintain cementum
Pulp cavity
- What is it made of
- What is it lined by
- Ageing causes
LCT and extensive nerves and vessels transit through apical foramen
Lined by odontoblasts
With age, there is decrease in size (due to life time secretion of dentin)
What can the pulp cavity be divided into
Pulp chamber (cavity of the crown)
Root canal (pulp in root of tooth)
Give some supporting tissue
Gingiva (gum)
Gingival sulcus
Periodontal ligament
Gingiva
- what is it
- classify
- How is gingiva oriented to bone?
Cutaneous mucous membrane moistened by salivary glands
Stratified squamous epithelium w/DICT
Anchored to bone
Gingiival sulcus
- What
- Classify
- Attachment
Wedged shaped potential space btw gingiva and anatomical crown
(bacteria and debris can get stuck here)
Cutaneous mucous membrane= stratified squamous epithelium and DICT
Epithelium attached to neck of tooth at bottom of gingival sulcus
(junctional epithelium at site of attachment)
Periodontal ligament
- purpose
- made of
- reflex
Suspends tooth ina alveolus (shock absorber)
Made of coarse type 1 collagen and Sharpey’s fibers anchor ligament in alveolar bone and cementum
Jaw-jerk reflex= muscles relax when bite on something hard…proprioceptive nerve endings sense tooth location.
Periodontal disease
Destruction of suspensory apparatus of tooth
Initiated by food/debris in gingival sulcus
Inflammation/bacteria can lead to destruction of alveolar bone and periodontal ligament
Epithelial attachment of gingiva forced onto exposed root
Teeth cleaning
Every 6-12 mo to clean gingival sulcus
Expands life span avg 3 yrs
Hypsodont teeth example species
All horse teeth
Tusks of pig
Cheek teeth of cattle and ruminants
Crown, root, and neck of hypsodont tooth
Crown=long w/enamel
Root=short w/no enamel
Neck= hard to define
Cementum of hyposodont tooth
Cememntum is deposited on entire surface of tooth (covers enamel)
Infundibulum and cup of hypsodont tooth
Infundibulum: surface invagination lined by enamel, covered by cementum
Cup=cavity in center of infundibulum
Enamel crest of hyposodont tooth
Projections of enamel on occlusal surface
Enamel wears away until dentin is exposed
