Teeth Flashcards
Enamel
Hard Brittle 2mm thick Translucent Covers anatomical crown
Dentine
Specialized CT
Hard
Strong and resilient
Dentinal tubules
Cementum
Tooth support
Resistant to reabsorption
Covers tooth roots
Mineralised CT
Tooth sections
Enamel Amelodentinal Junction Dentine Cementum Pulp
Tooth development- epithelium
(ectoderm)
Enamel
Hyaline layer of root
Tooth development- Mesenchyme
(ectomesenchyme)
Dentine
Pulp
Cementum
Peridontium- peridontal ligament and bone
First sign of tooth development
6 weeks (iul)
Bud stage
Spherical epithelial condensation
Cell proliferation
No histodifferentiation or morphogenesis
Cap stage
Cap shaped enamel organ
Poorly histodifferentiation
Little morphogenesis
Late cap stage
Some histodifferentiation- inner and outer enamel epithelium
Some morphogenesis
Early bell stage - Enamel organ
Inner enamel epithelium - form amaloblast (enamel) Stratum intermedium Stellate reticulum Outer enamel epithelium
Early bell stage - ectomesenchyme
Dental papilla -forms odontoblasts (dentine) and pulp
Dental Follicle
-forms cementum, PDL and bone
Dentinogenesis
Cytodifferentiation - dental papilla cells form odontoblasts Matrix formation - Odontoblasts produce predentine -collagen rich -Odontoblasts retreat inwards -Odontoblasts have a long cell process - forms dentinal tubule
Mineralisation
- predentine mineralizes forming dentine
Amelogenesis
Inner enamel epithelium produces ameloblasts
Ameloblasts secrete enamel protein matrix
Virtually immediate mineralisation
- rapid increase to 30% mineral - immature enamel
Gradual maturation
- further mineralisation to 96%
- requires removal of most of the enamel proteins
Root formation
Root = Dentine + cementum> derived from ectomesenchyme
Requires epithelial signal for initiation > root sheath
Enamel structure
Tightly packed hydroxyapatite crystals
Basic unit = enamel prism
Enamel prism is made of …
Prism core and prism sheath
Prism core
Tightly packed hydroxyapatite crystals
Prism sheath
Boundary of clearly different crystal orientations
Crystals less tightly packed
More space for organic components
What are striae
Incremental growth lines
What are the shallow furrows where striae reach surface called
Perikymata
What do dentine tubules contain
Cell processes
Nerves
Fluid -flows out
Is dentine innervated ?
Yes but only in inner aspect
Primary dentine
Formed during tooth development
Secondary dentine
Formed after root completion slowly throughout life of tooth
Tertiary dentine
Response to pulpal insult
What happens to pulp volume with age
Decreasesb
What are the two types of cementum
Acellular and cellular
