BDS3 revision

Question 1

what are the 3 theories of how orthodontic tooth movement occurs

Answer 1

piezo electric - historical
mechano-chemical - bunching of osteoblasts in compression areas allows osteoclast action
differential pressure - tension sees deposition, compression sees resorption

Question 2

light pressure for orthodontic tooth movement impact at cell level

Answer 2

hyperaemia at tension and compression sides
PDL has time to remodel
(gingival fibres stay distorted - main reason for relapse)

Question 3

hyalinisation

Answer 3

cell death due to blood vessel occlusion - leaves a cell free zone

seen in root resorption and when moderate forces used for tooth movement

Question 4

consequences of excessive forces for tooth movement

Answer 4

root resorption
loss of vitality
loss of anchorage

Question 5

how does mandibular growth occur after birth

Answer 5

surface deposition
growth at cartilages - mainly condylar cartilage

Question 6

3 methods of facial growth

Answer 6

sutures - joints between intramembranous bones
synchondroses - cartilaginous joint that pushes bone apart
surface depositon - remodelling

Question 7

2 theories of facial growth

Answer 7

cartilaginous - cartilage generates forces
functional matrix - growth of functional units stimulates growth e.g coronoid in response to temporalis growth