#4 Tooth Movement Flashcards
(30 cards)
What is the width of the PDL?
0.5mm (perio says 0.25mm ….)
The PDL is adapted to resist ______ duration forces.
short (seconds)
Force magnitude and duration are both very important because a force as little as ____ gm can induce tooth movement.
2 gm
T or F, PDL fibers need to be remodeled for tooth movement.
True, the remodeling mostly done by fibroblasts.
_____ is required for tooth moment beyond the PDL space.
Bone resorption
_______ are responsible for bone resorption.
Osteoclasts (multinucleate, produce acid and enzymes that remove bone)
What are the theories of tooth moment?
- The bioelectrical theory - bony changes caused by electric signals:
- Force induces induces piezoelectical signals
- Bioelectrical potential changes cell activity - The pressure-tension theory = bony changes caused by chemical signals
- pressure and tension alter blood flow.
- formation and release of chemical messengers
- Chemical messengers change cell activities.
How long does it take to displace tooth in PDL space?
1-2 secs light pressure
How long does it take to alter blood flow?
3-5 sec of light pressure
What happens after minutes of sustained light pressure?
Oxygen tension at compression side decreases -> Prostaglandins (PG-E) and cytokines (IL1) release)
What happens after hours of sustained light pressure?
Chemical messengers cause metabolic change; second messengers (such as cAMP) release –> osteoclasts recruitment (from blood), maturation and activation –> frontal bone resorption (good)…
How long does it take for tooth to move beyond the PDL space with sustained light pressure?
2 days
What happens within minutes of heavy sustained pressure?
Blood flow is cut off to compressed PDL and after a few hours cell death occurs in compressed area.
What happens within 3-5 days of heavy sustained pressure?
Osteoclasts recruitment from bone marrow), maturation and activation –> undermining bone resorption (Bad)
How long does it take for tooth to move beyond PDL space with heavy sustained pressure?
7-14 days
How is the movement of movement of teeth different over time with heavy vs. light force?
Light force = continued steady movement
Heavy force = Choppy, stop and go movement
How many hours a day of sustained force is needed to activate cellular activity?
4-8 hrs/day *longer duration produces more efficient tooth movement
The compression area larger during _____ that ______.
Translation than tipping *Greater force is needed to produce the same pressure.
Is movement faster in the Maxilla or mandible?
Maxilla * Bone density
What drugs inhibit tooth moment?
Prostaglandin inhabiters: NSAID, Corticosteroids
Bisphosphates
What methods can accelerate tooth Movement?
Local injury: regional acceleratory phenomenon (RAP)
Corticotomy Assisted tooth movement (Wilckodontics)
Is anchorage needed for reciprocal space closure?
No! because both teeth are moving to close a gap.
What is stationary anchorage control?
Only allows bodily movement of the molars, which requires stronger pressure.
What is skeletal anchorage?
Use temporary anchorage devices (TAD’s) to prevent unwanted movement.
