Fixed Orthodontic Appliances Flashcards
1
Q
What is fixed appliances?
A
- an appliances which is fixed to teeth and cannot be removed by patient
- consists of brackets, bands, archwires and auxillaries
- precision tooth movers
2
Q
FA vs Removable
A
3
Q
When do we use fixed appliances?
A
- correction of mild to moderate skeletal discrepancies (camouflage)
- alignment of teeth
- correction of rotations
- centreline correction
- OB and OJ reduction
- closure of spaces
- vertical movements of teeth
4
Q
Andrew 6 Keys
A
- tight approximal contacts with no rotations
- class 1 molars
- class 1 incisors
- flat occlusal plane/ slight curve of spee
- long axis of teeth have a slight mesial inclination except lower incisors
- crowns od canines back to molars have a lingual inclination
5
Q
Components of Fixed Appliances
A
- bracket/ tube
- archwires
- band
- modules
- auxillaries
- anchorage components
- force generating components
6
Q
Brackets
A
Components
- bracket slot
- tie wings
- bracket base
Materials
- Metal SS, CoCr, Ti, Au
- Polymers
- Ceramics
7
Q
Bands
A
- SS with pre-welded attachments
- require space before placement -> seperator visit
8
Q
What does bracket prescription mean?
A
determines tip, torque, and in/out control
9
Q
Bonding to teeth
A
- Comp via acid etch technique
- used for brackets
- photo- initiation reaction using light cure 440-480nm wavelength of light
- micromechanical retention
- GI for molar bands
10
Q
Archwires
A
- SS**
- Nickel Titanium**
- CoCr
- Beta Titanium (TMA)
- composite/ glass
11
Q
Why Nickel titanium arch wires?
A
- flexible
- light continuous force
- shape memory, can return to original shape, cannot bend
- higher friction than SS
12
Q
SS
A
- working archwires
- slide teeth as low friction
- formable for archwire bends and loops
13
Q
Force generating components
A
Sliding mechanism
- elastic power chain
- NiTi coils
- Intra- oral elastics
- active ligature
- teeth move by utilising energy stored in elastic/ spring
14
Q
What is anchorage?
A
- resistance to unwanted teeth movement
- Newton 3rd law: every force has an equal but opp reactionary force
15
Q
Simple anchorage
A
16
Q
Compound anchorage
A
17
Q
Reciprocal anchorage
A
18
Q
Absolute anchorage
A
- Temporary anchorage devices (TADS)
- non- osseointegrating mini screws - Major development in orthodontics
- anchorage control
- tooth movement mechanics
19
Q
Cortical anchorage
A
- cortical plates provide resistance to tooth movement
- maintains intermolar width
- nance palatal arch utilises palatal vault for anchorage reinforcement
20
Q
Intermaxillary anchorage
A
24
Q
Hawley removable retainer
A
- labial bow to control incisors and canines
- not well tolerated in lower arch
