Odontogenesis and Tooth development Flashcards
what is the periodontium made of
gingivia, periodontal ligament, cementum, alveolar bone proper
when do ectoderm/mesenchyme interactions occur
before any of the 6 stages of tooth development
what layers play an instructional role during the pre-tooth bud stage of tooth formation
ectoderm (epithelium) and mesenchyme (neural crest cells)
what does the epithelium/ectoderm do in tooth development
specifies the dental nature of mesenchyme
what does the mesenchyme do in tooth development
specifies the tooth type and nature of product produced by epithelium
what does the dental papilla differentiate into
pulp and dentin
what does the dental follicle differentiate into
PDL, cementum, and alveolar bone proper
what are the 6 stages of tooth development and what happens in each
- initiation: cellular induction
- bud stage: cellular proliferation
- cap stage: proliferation, beginning of differentiation and morphogenesis
- bell stage: proliferation, differentiation, and morphogenesis. all parts of the enamel organ are visible
- apposition: induction and proliferation. mineralized tissues grow against each other
- maturation: maturation, calcification of more proteinaceous matrices
when does initiation/induction stage occur and what specifically happens
6-7th week
-invagination of the ectoderm into the mesenchyme forms the dental lamina
when does the bud stage occur and what specifically happens
8th week
- vestibule occurs through apoptosis of mesenchyme to make room for the oral ectoderm to make the primitive gut
-proliferating oral ectoderm makes transition into dental lamina
when does the early cap stage occur and what specifically happens
9-10th week
-apoptosis results in creation of buccal vestibule
what layers form in the cap stage
-outer enamel epithelium
-inner enamel epithelium
-stellate reticulum
-dental papilla
-dental follicle
what do cells in the stellate reticulum do
supportive cells, hold shape of enamel organ
what do the cells in the dental papilla do
undifferentiated cells making their way up into the inner enamel epithelium and eventually forms pulp and odontoblasts
what does the dental follicle do
encapsulates the enamel organ and eventually forms the periodontal ligament, cementum, alveolar bone
what layers are visible in the bell stage
all layers are distinguishable and enamel organ can be differentiated
what makes up the enamel organ
outer enamel epithelium, inner enamel epithelium, stellate reticulum, stratum intermedium
what type of cells are in the outer enamel epithelium and what is their function
-cuboidal cells
-protective barrier
what type of cells are in the inner enamel epithelium and what is their function
cuboidal cells
- differentiated into ameloblasts (enamel)
what type of cells are in the stellate reticulum and what is their function
-star shaped cells forming network inside enamel organ
- supportive function in enamel production
what type of cells are in the stratum intermedium and what is their function
-compressed layer of flat cuboidal cells
-supportive function in enamel production (makes alkaline phosphatase)
what type of cells are in the dental follicle/sac and what is their function
-collagen fibers around enamel organ
- differentiate into cementum, periodontal ligament, and alveolar bone
what type of cells are in the dental papilla and what is their function
-cells nearest IEE have basement membrane separation
-outer cells differentiate into odontoblasts and inner cells differentiate into pulpal tissue
what occurs with the inner enamel epithelium in the apposition stage
IEE starts cuboidal (inactive)and becomes columnar (active)
-pre ameloblasts have receptors (fibronectin) that attract dental papilla cells (pre-odontoblasts)
