melfi 1 Flashcards
What is the only direction a tooth does NOT move normally?
apically
Does tooth movement occur throughout life?
yes
What cells are involved in eruption?
cells of the PDL:
cementoblasts, osteoblasts, osteoclasts (from bone marrow), fibroblasts
What functions do fibroblasts serve in the PDL?
secretes extracellular substance
lysis extracellular substance (“fibroclast”)
can become a contracting cell called a fibromyocyte myofibroblast
How does a fibromyocyte (myofibroblast) work?
cell is connected by integrins to principle collagen fiber bundles that connect the tooth to alveolar bone. when the cell contracts the collagen fibers contract, moving the tooth
What glycoprotein exhibits properties that serves as an integrin that binds to extracellular components such as collagen?
fibronectin
What are the three stages of eruption
- Preemergence
- Prefunctional
- Functional
What is the main direction of movement in the preemergence stage
facially
What is the main direction of movement in the pre functional stage
occlusally
What is the main direction of movement in the functional stage
mesially
What important events occur during pre emergence stage
appearance of tooth germ appearance of crown dentin appearance of pulp chamber enamel formation enamel organ becomes REE Hertwig's sheath forms (determines # root canals)
What is the make up of immature enamel?
70% organic (mature is 1% organic)
What are the two main functions of Hertwig’s epithelial root sheath
determines # of root canals
determines root dentin outline
During the pre emergence stage, are roots present?
NO but the number of root canals is determined by HERS
What attaches the REE to enamel
basal lamina