Physiology Of Tooth Movement Flashcards
What types of tooth movement are there?
Tipping
Bodily movement
Intrusion
Extrusion
Rotation
Torque
What are the optimum forces for each type of movement?
Tipping, extrusion and rotation = 35-60g
Intrusion = 10-20g
Bodily movement = 150-200g
Torque = 50-100g
What is the difference in movement in light and heavy forces?
Light forces exhibit a linear slow movement of teeth
Heavy forces have a rapid movement, followed by periods of stasis, then period of movement.
How does duration of force affect tooth movement?
As duration in hrs/day increases, the % efficiency of tooth movement increases then plateaus
What deterioration can occur from orthodontic movement?
Root resorption
Pulpal changes
Pain and mobility
Loss of alveolar bone
Relapse of tooth position
What occurs in light forces when moving a tooth?
Force causes hyperaemia in blood flow to PDL
Osteoclasts then appear on pressure side and osteoblasts on the tension side.
Osteoclasts resorb lamina dura on pressure side while osteoblasts lay down osteoid matrix on the tension side in the new PDL space
This is frontal resorption
What occurs when moderate forces act on a tooth?
Increased force causes occlusion of blood vessels on the pressure side and hyperaemia of vessels on the tension side
Cell free areas on pressure side due to increased pressure (hyalination)
Period of Stasis followed by increased vascularirty on underside of bone supporting tooth leads to a sudden move in the desired direction.
What occurs with heavy forces On a tooth?
Occlusion of blood vessels leading to necrosis of PDL and bone occurs, areas of cell free hyalination areas occur and also resorption of root surface