1 - Basic Tooth Struture Flashcards
Name main parts of tooth and surrounding areas (7)
Enamel Dentine Pulp Cementum Periodontal ligament Alveolar bone Gingival tissue/Oral mucosa
Enamel:
Covers ____
Derived from ___
Vital or non vital?
Describe the structure of enamel
Covers anatomical crown
Derived from ectoderm
non-vital/acellular therefore cannot repair itself
Hard but brittle
96% Ca HA, 2% enamel proteins, 2% water
Made from enamel rods (mass of HA crystals)
Orientation of crystals determines rod boundaries
Dentine:
Forms bulk of ___
Derived from ___
Vital or non vital?
Describe the structure
Forms bulk of crown and root
Derived from ectomesenchyme
Vital - can repair to some extent
70% Ca HA
30% collagen (type 1)
Made from dentinal tubules - contain odontoblast cell processes extending from cell bodies at pulp-dentine boundary
Odontoblasts don’t die - remain in quiescent state but can be reactivated and repair to some extent
Pulp:
Found in ___
Derived from ___
Vital or non-vital?
Describe the structure and main structures found in pulp
Found in pulp chamber in crown and root canals
Derived from ectomesenchyme
Vital
Has a layer of highly specialised odontoblasts on outer borders of pulp
Contains: pulp horn, root canal, coronal pulp, radicular pulp
Cementum:
What is it/what does it cover
Derived from ___
What are the 2 variations of cementum
What 2 types of fibres contained in cementum
Thin layer of bone like tissue covering tooth roots
Derived from ectomesenchyme
Acellular - thin - covers cervical root
Cellular - thick - covers apical root
Extrinsic collagen fibres - acellular & cellular
Intrinsic collagen fibres - cellular
What are the periodontal tissues found in the tooth structure
Periodontal ligament
Alveolar bone
Gingiva/mucosa
Periodontal ligament:
Is a ___
Derived from
Connects cementum to ____
Describe the structure
Is a dense fibrous tissue
Derived from ectomesenchyme
Connects cementum to: alveolar bone, adjacent teeth, gingivae
Fibrous stroma in a gel of ground substance containing blood vessels and nerves. Stroma consists of collagen with fibroblasts interspersed and neurovascular bundles
Collagen fibres arranged in different orientations to absorb masticatory load
Withstands force in axial orientation best
Reforms during orthodontic treatment
Alveolar bone:
What does it form
Give its composition p
What are the two parts/structures of alveolar bone
Forms tooth sockets and anchor for PDL
Inorganic contents: 67% = HA
Organic contents: 33% = collagen (28%) & non collagenous proteins (5%)
- Alveolar bone proper - direct contact with root of tooth
- Supporting alveolar bone - consists of cortical and trabecular bone
BOTH have nerves blood vessels and fibres
Gingival tissue / oral mucosa
For both individually:
Colour?
Where is it found?
Structure (histology)
Gingiva:
Pink
On alveolar bone
Keratinised
Oral mucosa:
Red
Lines oral cavity
Stratified squamous epithelium
Can be:
Keratinised in areas of high abrasion (tongue, hard palate etc.)
Non keratinised in areas of low abrasion (oral surface of cheeks lips floor of mouth etc.)
Primary dentition:
When does it develop
How many teeth?
How many in each quadrant?
What are these/what types of teeth in each quadrant
From 6 months - 2 years
20 teeth
5 per quadrant
2 incisors, 1 canine, 2 molars
Permanent dentition:
When does it replace primary dentition?
How many teeth?
How many in each quadrant?
What are these/what types of teeth in each quadrant
From 6-12 years
32
8 per quadrant
2 incisors, 1 canine, 2 premolars, 3 molars
