Fixed appliances

Question 1

What 4 movements can fixed appliance allow?

Answer 1

1. Tipping
2. Intrusion
3. Extrusion
4. Bodily movement

Question 2

What is the mode of action for fixed appliances?

Answer 2

Appling a mechanical force couple to the crown, in conjunction with simple forces can achieve rotation, apical and bodily movement

Question 3

Give 2 advantages and 2 disadvantages of buccal fixed appliances:

Answer 3

Advantages:
1. Good access
2. Reduced working time

Disadvantages:
1. Poor aesthetics
2. Decalcification very visible

Question 4

Give 2 advantages and 2 disadvantages of lingual fixed appliances:

Answer 4

Advantages:
1. Good aesthetic
2. Decalcification not visible

Disadvantages:
1. Poor access
2. Longer working time

Question 5

What is the most aesthetic but expensive alternative for buccal fixed appliances?

Answer 5

Ceramic (clear) brackets

Question 6

Give 3 properties of arch wires:

Answer 6

1. Spring back
2. Stiffness
3. Resilience

Question 7

What are the 2 most common materials of arch wire?

Answer 7

1. Stainless steel
2. Titanium alloys

Question 8

Give 4 potential effects of excessive force on teeth:

Answer 8

1. Pulpal death
2. Root resorption
3. Pain
4. Mobility

Question 9

Give 4 reasons why we use retainers after fixed appliances:

Answer 9

1. To minimise relapse
2. To hold teeth into new position
3. To allow remodelling of PDL and fibres
4. Long term stability

Question 10

What are the 3 types of retainers?

Answer 10

1. Removable retainers
2. Vacuum formed retainers
3. Fixed retainers