Anchorage

Question 1

What factors affect anchorage?

Answer 1

• number of teeth to be moved
• distance to move teeth
• type of tooth movement
• root surface area
• skeletal pattern
• occlusal intercuspation
• tendency for tooth movement in the arch

Question 2

What is the definition of anchorage?

Answer 2

The resistance to unwanted tooth movement

Question 3

How can anchorage be supplemented?

Answer 3

• extraction decisions
• bond the second molars
• lingual arch
• transpalatal arch +/- nance button
• intermaxillary elastics
• fixed class II traction
• functional appliance
• removable appliance - baseplate, palatal coverage
• implants - restorative, TAD, mini screws

Question 4

How can anchorage strains be reduced?

Answer 4

• tip rather than bodily movements
• light forces
• decrease friction - self ligating brackets
• separate retraction on individual teeth
• push rather than pull
• correct the centre line one tooth at a time

Question 5

What are the sources of anchorage?

Answer 5

• simple
• compound (intra or intermaxillary)
• stationary
• reciprocal

Question 6

How does a TPA assist with anchorage?

Answer 6

Maintains the inter molar width

Question 7

What factors affect anchorage?

Answer 7

• number of teeth to be moved
• distance to move the teeth
• type of tooth movement - bodily needs more
• root surface area of anchor teeth
• skeletal pattern - increased vertical height are more at risk of anchorage loss
• occlusal intercuspation
• tendency for tooth movement

Question 8

How can anchorage loss sometimes be useful?

Answer 8

Burning anchorage - when the overjet is average but there are still spaces present

Question 9

What is simple anchorage?

Answer 9

One tooth against another

Question 10

What is stationary anchorage?

Answer 10

Use of TADS, implants, ankylosed teeth

Question 11

What is reciprocal anchorage?

Answer 11

Equal forces applied to equal teeth which causes equal movement towards each other - for example using powerchain on a midline diastema

Question 12

What is compound anchorage?

Answer 12

More than one tooth in an anchor unit
Intra maxillary - same arch
Inter maxillary - opposing arches - class II / III traction

Question 13

What are reasons for anchorage loss?

Answer 13

• forces too heavy
• maxillary arch is more susceptible
• occlusal interferences
• vertical growth pattern
• poor patient compliance - not wearing ura/headgear/elastics, fixed appliances with lots of breakages

Question 14

How can anchorage be reinforced?

Answer 14

• increase teeth in anchor unit
• making movement of anchor teeth more difficult
• intermaxillary elastics
• palatal/lingual arches

Question 15

What dimensions should be considered with anchorage?

Answer 15

All dimensions - AP, lateral and vertical