8 - Fixed appliances Flashcards
(30 cards)
Define fixed appliances.
- fixed to teeth and cannot be removed by patient
- consist of brackets, bands, archwires and auxiliaries
- precision tooth movers
What are the properties of fixed appliances?
- 3D control
- complex tooth movements
- less dependant on compliance
- require excellent OH
- risk of iatrogenic damage
- poor intrinsic anchorage
What are fixed appliances used for?
- correction of mild/moderate skeletal skeletal discrepancies (by camouflage)
- alignment of teeth
- correction of rotations
- centreline correction
- OB/OJ reduction
- closure/opening of spaces
- vertical movements of teeth
What are Andrew’s six keys?
- tight approximate contacts with no rotations
- class I incisors
- class I molars
- flat occlusal plane or slight curve of spee
- long axis of teeth have slight mesial inclination except molars
- crowns of canines to molars have lingual inclination
What are the components of fixed appliances?
- bracket/tube
- band
- archwires
- modules
- auxiliaries
- anchorage components
- force generating components
What are the components of a bracket?
- bracket slot
- tie wings
- bracket base with prescription incorporated
What materials can brackets be made of?
- metal (SS, CoCr, Ti)
- polymers
- ceramic
What does the blue dot indicate on a bracket?
- positioning
- should be gingival an distal to achieve correct prescription
What are molar bands for?
Increased anchorage
What is tip?
- mesial/distal angulation of tooth
- determined by the angulation of slot on bracket
What is torque?
- buccal/lingual angulation of tooth
- determined by angulation of bracket base
How are brackets bonded to teeth?
Composite via acid etch
How are molar bands bonded to teeth?
Glass ionomer
What are the common materials used in archwires?
- stainless steel
- nicket titanium
What are stainless steel archwires primarily used for?
Moving teeth
What are nickel titanium archwires primarily used for?
Light forces
What are the properties of NiTi archwire?
- flexible
- light continuous force
- shape memory (not formable)
- higher friction than SS
What are the properties of SS archwire?
- working archwire
- low friction
- formable (bends or loops)
What is the function of bumper tubing?
Protect wire at extraction sockets
What are force generating components?
- elastic power chain
- NiTi coils
- intra-oral elastics
- active ligature
What is power chain?
- elastomeric chain that exerts additional force on teeth
- degrades quickly so requires replacement regularly
What are NiTi coils used for?
Push teeth apart
What is simple anchorage?
Root surface area
What is compound anchorage?
Link teeth together to increase root surface area for anchorage
