Anchorage

Question 1

What is anchorage?

Answer 1

Resistance to unwanted reciprocal tooth movements

Question 2

What is the rate of tooth movement related to? And what is this theory called?

Answer 2

Differential theory stages that: level force per unit root area over a certain range of force

Question 3

What are the sources of intraoral anchorage?

Answer 3

root surface area
teeth in same arch
palate
opposing teeth
implants/TAD

Question 4

What is EO anchorage and What are sources of E/O anchorage?

Answer 4

This is when the force to move the teeth is from the outside head gear attaching onto cranial bones

Question 5

What is loss of anchorage?

Answer 5

movement of the anchor teeth during orthodontic treatment

Question 6

What is excessive loss of anchorage?

Answer 6

UNWANTED movement of anchor teeth during orthodontic treatment which prevents dsired tooth movement from occurring

Question 7

How can we prevent LOA?

Answer 7

move small number of teeth at any one time
keep active forces light
make anchorage root area as large as possible

Question 8

Which requires more anchorage, full bodily movement or tipping?

Answer 8

full bodily movement as there is more area for which bone has to resorb

Question 9

What is the disadvanage of intermaxlliary anchorage?

Answer 9

this can sometimes lead to the over eruption of posterior teeth and reduction of the overbite

Question 10

What are the groups os intra oral traction?

Answer 10

simple: one tooth
compound: several teeth
reciprocal: 2 groups of teeth are pitted against eachother so get movements in both sets, this is needed in palatal expasion

Question 11

When would we use head gear?

Answer 11

to move all teeth distally

when there is not enough I/O anchorage

Question 12

What are the two types of head gear?

Answer 12

cervical pull

high pull

Question 13

How does cervical pull work?

Answer 13

this is at the level of the occlusal plane and causes the upper molars to extrude so cannot be used in people with increases lower facial height

Question 14

How does high pull head gear work?

Answer 14

this is placed above the occlusal place

Question 15

How long does the head gear need to be worn?

Answer 15

10/12 hours

Question 16

How much force is exerted by hed gear?

Answer 16

200-250g

Question 17

WHat do TAD create?

Answer 17

temporary anchorage device

they provide absolute anchorage

Question 18

Tooth moving forces create equal and opposite forces according to who?

Answer 18

Newtons third law

Question 19

How can we monitor anchorage?

Answer 19

By recording each visit the extent of movements you want to happen

Question 20

What is the root surface area of upper incisor?

Answer 20

Central: 2.2cmsq
Lateral: 1.8cmsq

Question 21

What is the root surface area of an upper canine?

Answer 21

2.7cmsq

Question 22

What is the root surface area of an upper second premolar?

Answer 22

2.3cmsq

Question 23

What is the root surface area of an upper molar?

Answer 23

4.6cmsq

Question 24

Anchorage within one jaw is known as what?

Answer 24

Intra maxillary

Question 25

Anchorage across jaws is knows as?

Answer 25

Intermaxilliary

Question 26

What are the components of head gear?

Answer 26

1. Headcap
2. Elastic bands
3. Facebow/whiskers
4. J Hooks

Question 27

How much force is needed to tip a tooth?

Answer 27

25-60g

Question 28

How much force is needed to bodily move a tooth?

Answer 28

50-120g

Question 29

How much force is needed to torque a tooth?

Answer 29

50-100g

Question 30

How much force is needed to rotate a tooth?

Answer 30

35-60g

Question 31

How much force is needed to extrude a tooth?

Answer 31

34-60g

Question 32

How much force is needed to intrude a tooth?

Answer 32

10-20g

Question 33

What level of force must be not exceeded during tooth movement?

Answer 33

30mmHg
Because this is the pressure in capillaries and above this the capillaries will occlude and this then leads to hyalinasation of the pdl

Question 34

How does bone resorb under physiological conditions ie. When the amount of force exerted by the brace does not exceed the capillary force?

Answer 34

1. Osteoclasts are formed by the fusion of blood monocytes which then resorb bone under the control of osteoblasts

Question 35

How does bone resorb in ortho when there has been death of the pdl?

Answer 35

Osteoblasts and osteoclasts that would be returned from the pdl are not available and for frontal resorption of bone
This means bone remodelling would be otherwise performed by cells migrating from Undamaged areas of pdl which may take several days therefor in these circumstances bone is resrobed outward a by osteoclasts lining the marrow spaces from the cancellous bone to the pdl.

Question 36

What is the type of bone resorption that takes place in hylanisee pdl?

Answer 36

Undermining resorption

Osteoclasts resorb the bone from the cancellous bone to the pdl

Question 37

When the pdl is hylainsee bone resorption is faster. T/F

Answer 37

F

Delay of 10-14 days

Question 38

What is there more likely to be as a consequence of hylaisation?

Answer 38

LOA
This is because the force maybe too strong or the tooth in question but form the remaining anchor teeth the force maybe just the right level

Question 39

Why does bodily movement have greater optimal force levels that the other types of movements?

Answer 39

Because a greater area of pdl is involved and thus more force can be applied

Question 40

What happens if toot much force is used to intrude teeth?

Answer 40

Since only a small amount of pdl is involved

1. Root resorption
2. Tooth devitalisation as the apical blood is constricted

Question 41

What does class 2 Intermaxilliary anchorage look like?

Answer 41

From upper 3’s to lower 6’s

Question 42

What does class 3 Intermaxilliary anchorage look like?

Answer 42

Fro lower 3’s to upper 6’s