What is the force needed for Intrusion?
10-20g
What is the force needed for Tipping?
30-60g
What is the force needed for Rotation?
30-60g
What is the force needed for Extrusion?
30-60g
What is the force needed for Torque?
50-100g
What is the force needed for Bodily movement ?
60-120g
What are the cells involved in bone remodelling?
Osteoblasts
Osteoclasts
Osteocytes
What is the origin of OSTEOBLASTS?
- Originate from mesenchymal stromal cells
- Lie on the surface of bone
What is the origin of OSTECLASTS?
- Originate from blood monocytes
- Multinucleated cells
What is the Hormone responsible for tooth movement ?
PROSOGLANDIN
What is the result of using HIGH forces ?
HIGH FORCES = undermining resorption
- Occlude the capillaries > cell death NECROSIS > process called HYALINISATION
- Tooth movement is delayed and bone commences from marrow spaces beneath the necrosis area after a few days. (10-14days delay)
- Osteoclast have to migrate from adjacent undamaged areas
What is FORCE?
Force = vector that can be described by magnitude and directions
Components of force = moment of a force and couple
What is the role of OSTEOBLASTS in bone remodelling?
Responsible for production of bone organic matrix and mineralization
- Recrut and activate osteoclast via produvtion of cytokines
- Main regulator of bone remodeling
What is the role of OSTEOCLASTS?
- Responsible for bone resorption
What is a force couple?
- 2 opposite and equal forces act to cause pure rotation
What is Centre of resistance and where?
point in the body where the resistance is concentrated
single rooted tooth - halfway down the root
multi rooted tooth - furcation area
What are the components of Force?
moment of a force and couple
Moment of force calculation ?
- tends to cause rotations
- calculated as:
MAGNITUDE of the force x Perpendicular DISTANCE from the point of force application to the centre of resistance of a tooth
