11. Tooth Movement Flashcards
Resorption occurs (ahead/behind) the moving tooth
ahead
Osteoblasts are positioned (infront of/behind) drifting tooth
behind
What is osteoid bone
- organic bone matrix
- This is what is initially laid down by osteoblasts
Osteoid bone is (more/less) prone to resorption
less (thus more resistant to resorption)
What changes occur with the tooth pulp during ortho movement
- Increased hyperemia (may have thermal sensitivitiy)
- Excessive forces may cause pulp degeneration
Changes to cementum as result of ortho movement
- -Cementoid may perforate with semilunar areas of resorption in cementum
- Cementoblasts fill in “punched out” areas after active movement
Changes in dentine in response to tooth movemenet
- Severe forces perforate cementoid layer –> cementum and dentin resorption
- Cementoblasts may repair dentine
Changes in enamel with tooth movement
none- caution with decalcification (brackets)
Describe bone deposition and resorption patterns with a tooth crown tipped palatally
- Deposition at center of rotation
- Most resorption at the palatal crease
- Most compression of PDM at alveolar crest
- Increased PDM thickness apically
On the side with the widened PDM (osteoclast/osteoblasts) are stimulated
osteoblasts
Excessive pressure has what consequences for PDM
- Crushed –> necrosis
- Stretched (tension side) –> fibers torn/ hemorrhage
Optimum force range to move a tooth
50-200 grams
Force through the center of mass causes _ movement
linear movement (no rotation) -- translational mvoement The root apex and crown move the same distance
When the line of force is not through the center of mass –> _ movement
tipping
Continuous heavy forces on teeth leads to
hemorrhage, stasis and necrosis
- Undermining resorption
- Tissue reorganization after clean up of necrotic debris
- Damaging**
Intermittent light force results in
- Allows recorvery
- Osteoid deposition on pressure side
- Resists resorption until calcified
- Slows orthodontic tooth movement
Continuous light force
- Bone directly resorbed
- Minimal undermining resorption and necrosis
- No osteoid bone
- Ideal ortho movement!! **
Reorganization of perio fibers is (slow/rapid) alveolar crest fibers = (slow/rapid)
rapid and slow
Hooke’s law
deflection is proportional to load (related to stiffness of an object)
Minimal change in force occurs with (low/high) stiffness springs
low
Deflection occurs up to
the elastic limit
High modulus and low modulus what do they mean in terms of stiffness
high modulus= high stiffness and low modulud= low stiffness
Loops and helicies in springs (increase/decrease) stiffness
decrease
