Biology of Tooth Movement Flashcards
What is the width of the PDL?
0.5mm
What is the job of osteocytes?
Most abundant cells in bone – Involved in cell signalling/responses to mechanical forces
What is the relation between the PDL and tooth movement?
The PDL has an intrinsic force which needs to be overcome before teeth move
Loss of PDL support – loss of force required – uncontrolled movement
What % of cancellous bone is calcified?
15-25% calcified with the remainder being bone marrow, CT and blood vessels
In terms of ortho teeth define centre of resistance
Point on the tooth when a single force is passed through it, it will bring about its translation along the line of action of the force
On average how much root can be resorbed during ortho tx?
1-2mm
What is the job of osteoclasts?
Responsible for bone resorption
What type of roots have an increased risk of resorption?
Blunt, short, pipette roots
What can be found in the cellular component of bone?
Osteoclasts
Osteoblasts
Osteocytes
What is an extra-oral anchorage device that is commonly used? What are its components?
HEADGEAR
* Uses Kloehn bow which attaches to headgear tubes on upper 6 bands to prevent mesial molar movement & loss of anchorage
* Can also be used to distalise molars by increasing forces needed to create space
What type of tooth movement is this?
How much force is required?
Bodily movement
100-150g
What factors of ortho tx can increase the risk of root resorption?
Long treatment time
Use of class II elastics
Pushing roots into cortical plate
Tartrate resistant acid phophatase (TRAP) is secrected by osteoclasts. What is its role?
Important for differentiation, activation and proliferation of osteoclasts
What are the two components of bone?
Matrix (organic and mineral)
Cellular
What does the anchorage value of a tooth mean? What increases this value?
Anchorage value of a tooth is proportional to the surface area of the root
The tooth with larger root surface area requires greater force to move (higher anchor value)