Embryology of tooth development 2 Flashcards
What branchial arch is dentine derived from
1st
How is formation of dentine induced
Interaction with epithelial cells of the enamel organ
What does the oral ectoderm turn into
Ectomesenchyme
What happens with the Internal enamel epithelium and pre- ameloblasts
They are constantly turning into ectomesenchyme
What do odontoblasts turn into
Ameloblasts
What are some types of dentine
Mantle Circumpulpal Globular Pre-dentine Peritubular Sclerotic Secondary
Characteristics of matrix vesicles
Extracellular
100 nanometer diameter, small
Membrane bound
They represent the first signs of mineralisation within an unmineralised matrix
Formed by polarised budding and pinching off of vesicles from specific regions of the outer plasma membrane of chondrocytes, osteoblasts and odontoblasts
Multi stage process of enamel formation
Secretion of an organic matrix Crystal nucleation Crystal elongation Removal of the organic matrix Crystal maturation
What occurs during enamel maturation
Decrease in ameloblast height and volume
Decrease in number of organelles
Cyclical removal of water and organic material with deposition of inorganic material
Smooth vs ruffled ameloblasts
Cyclical removal of water (smooth) and organic material with deposition of inorganic material (ruffled)
Unique proteins of the enamel matrix responsible for mineralisation
Amelogenins Tuftelin Ameloblastin Enamelins Proteinases (including MMP's)
How are roots formed
The cervical loop migrates downwards as a bilayer of epithelial cells to form Hertwigs root sheath
What leads to root odontoblast formation
Epithelial ectomesenchymal interactions take place between the root sheath and cells of the dental follicle
What does Hertwigs root sheath break down
Epithelial cell rest of malassez
