Physiology of Tooth Movement Flashcards
How much of the root length is lost during orthodontic treatment?
1-2mm.
What is the differential pressure theory of orthodontic tooth movement?
When a force is applied to the crown of a tooth, you create stressed in the PDL.
In areas where the PDL is compressed- we get bone resorption.
In areas of tension, we get bone deposition.
What type of tooth movement does a URA elicit?
Tilting and tipping of teeth only.
How much force do you want for tipping teeth?
35-60 grams.
What does a functional appliance do to the teeth?
Retroclines the upper incisors
Proclines the lower incisors
Distalises the upper teeth
Mesialises the lower teeth
What is the goal of a functional appliance?
Restrain maxillary growth and encourage mandibular growth.
Mandible is postured away from it’s normal rest position
- downwards and forwards.
What type of removable and fixed functional appliances are available?
Removable-
- Twin block
- Activator/bionator
Soft tissue borne- Frankel
Fixed- Herbst
What is a dental consequence once a twin block has been used?
Lateral open bite.
What tooth movements can be achieved through a fixed appliance?
Bodily movements
Torque
Intrusion
Extrusion
Rotation
What is Bodily movement of teeth?
Tooth and the root move together.
If the tooth moves in a medial direction, there will be resorption on the medial side and deposition on the distal side.
What is intrusive movement of teeth?
Tooth moving apically.
10-20 grams of pressure.
Bone resorption apicall- pressure of the supporting structure.
What is extrusive movement of teeth?
Teeth move coronally- tension is induced in the supporting structures and bone deposition occurs apically.
What is rotational movement of teeth?
Tooth rotated along its long axis.
35-60 grams required.
Requires an elastic chain to be attached palatally to pull tooth in opposite direction to buccal.
What is torque movement of teeth?
Apical root torque- root movement to change the inclination of a tooth.
