Orthodontic tooth movement

Question 1

What force is applied in order to orthodontically move teeth?

Answer 1

Centre of resistance

Question 2

Describe tipping forces and were are they greatest?

What dental appliance tips teeth?

Answer 2

Tipping forces are when the crown and root move in opposite directions

These are the greatest at the root apex and alveolar crest

Removable appliances

Question 3

Describe bodily forces and how it is applied:

Answer 3

Bodily forces occur when the crown and root move is the same direction

The force is applied through a force couple using fixed appliances ONLY

Question 4

When fibres within the PDL are stretched, list 3 chemicals which are activated:

Answer 4

Prostaglandins
Cytokines
Nitric Oxide

Question 5

How do osteoblasts and osteoclasts behave during tooth movement?

Answer 5

Osteoblasts = appear in tension sites and deposit bone

Osteoclasts = appear in the compression site and resorb the alveolar bone

Question 6

What is the role of fibroblasts during tooth movement?

Answer 6

Fibroblasts = help the remodelling of the PDL

Question 7

What can occur as a result of excessive forces on the roots?

What does resorption of necrotic tissues lead to?

Answer 7

Ischemia, cell death and tissue necrosis can occur from excessive root force

Resorption of necrotic tissues leads to resorption by cells which is called cementoclasts

Question 8

Where does bone resorption occur and what is it called?

Answer 8

Bone resorption starts below areas of necrosis and is called undermining resorption