Fixed Appliances in Orthodontics 1

Question 1

What are the types of movement in fixed appliances?

Answer 1

Tipping 
Bodily movement 
Rotation
Torque 
Vertical movements: extrusion and intrusion

Question 2

What are the problems with fixed appliances?

Answer 2

Enamel demineralisation
Root resorption - 0-1mm of root apex, reduces long-term prognosis
Periodontal problems - gingivitis/hyperplasia
Unwanted tooth movements
Pulp devitalisation
Soft tissue lacerations
Allergies

Question 3

What are the positives of using fixed appliances?

Answer 3

Good tooth alignment - corrects rotations, controlled tipping and torque control
Good space closure (bodily movement)
Excellent tooth alignment in planes

Question 4

What are the components of the fixed appliance?

Answer 4

Brackets
Molar tubes/bands
Arch wires
Auxiliaries

Question 5

What are the components of the bracket?

Answer 5

Tie wings on the corners and slots down the centre

Question 6

Which wire is used for the intital movement of teeth?

Answer 6

Ground arch wire - fully engaging the slot around the wire

Question 7

What is the slot diameter size?

Answer 7

0.022x0.028’’

Question 8

What is the max dimension wire used?

what happens if it exceeds this?

Answer 8

0.019x0.024

If bigger then will jam the slot, creating friction so high that the tooth cannot move

Question 9

Which wire is used for initial tooth alignment?

Answer 9

Round wires

Question 10

How are rectangular wires different?

Answer 10

0.019x0.025

Full 3D control

Question 11

What are rectangular wires used for?

Answer 11

Space closure and final alignment

Question 12

What are the different bracket materials?

Answer 12

Metal - SS
Ceramic
Plastic

Question 13

Why is the bracket base a mesh?

Answer 13

To increase SA and retention

Question 14

What 3 different aesthetic brackets are there?

Answer 14

Ceramic
Lingual SS
Plastic

Question 15

What is the problem with plastic brackets?

Answer 15

Fracture
Discolouration
Distortion

Question 16

What are the problems with ceramic brackets?

Answer 16

Fracture
Debonding - ceramic remnants left of the teeth
Abrasion to other teeth - can only be used in upper teeth so that cant wear lowers
Increased friction - treatment takes longer
Cost

Question 17

What’s the problems with lingual appliances?

Answer 17

Difficult technique
Cost
Traumatic to tongue

Question 18

What are the components of lower molar tubes?

Answer 18

Single tube for archwire and hook for auxilaries

Question 19

What are the components of upper molar tubes?

Answer 19

Additional hook for headgear

Hook for auxillaries

Question 20

What is used to place molar band on tooth?

Answer 20

Aquagem

Question 21

How long do you place separator on tooth before fitting molar band? Why place separators?

Answer 21

Place sepeartors for 1 week
More comfortable for patient
Easier for operator
More accurate band selection

Question 22

How are molar tubes placed on tooth?

Answer 22

direct bond - just stick on top

Question 23

What are the problems with molar tubes?

Answer 23

Difficult isolation from moisture - more likely to debond
problem with wire if debonds
Cant use with headgear
Don’t need to use separaors

Question 24

What is the function of archwires?

Answer 24

Active archwire - move the teeth with wire: light forces and flexible
Passive archwire - move teeth along the wire- rigid

Question 25

What are active archwires?

Answer 25

Nickel titanium - for alignment

Question 26

What are passive archwires?

Answer 26

Stainless steel, for bodily movement of teeth

Question 27

How is the force applied to an individual tooth controlled?

Answer 27

By varying the cross-sectional diameter and form of the arch wire and materials

Question 28

Why is flexible wire better at the initial stages of treatment?

Answer 28

flexible and good resistace to permanent deformation so that displaced teeth can be aligned without the application of excesive forces

Question 29

In later stages why use a rigid wire?

Answer 29

They engage the wire slot fully, and provide fine control over tooth position while resisting the unwanted effects of other forces e.g. elastic traction

Question 30

What are the properties of NiTi?

Answer 30

Flexible and elastic, can distort and bounce back
Super-elastic
heat-activated

Question 31

What are the cross-sectional dimensions for round and rectangular wires?

Answer 31

Round: 0.010’‘-0.020’’
Rectangular: 0.019x0.025

Question 32

What are the 3 ways of attaching arch wires?

Answer 32

Modules
Wire ligatures quick ties, tie arch wire into bracket more tightly
Self-ligating brackets

Question 33

What are auxillaries?

What are they used for?

Answer 33

Springs and elastics to close spaces

Question 34

What are the different elastics?

Answer 34

Elastic bands
Powerchain - elastic chain betweent the teeth
Zing string (power thread) - used when have impacted tooth, want to pull it out slowly
E-links
Traction ligatures - module on the end of stainless steel wire to close space as module contracts and closes the space

Question 35

What are the different springs used?

Answer 35

Push coil/coil spring - make space, can be SS or NiTi

Closing coil/retraction spring - to close the gap - NiTi has a more continuous level of force

Question 36

What is in the fixed appliance kit?

Answer 36

Weingarts - gripping archwires 
Tucker
Light wire pilers cutters
Crown shears 
Distal end cutters