Fixed Orthodontic Appliances Flashcards
What is fixed appliances?
- an appliances which is fixed to teeth and cannot be removed by patient
- consists of brackets, bands, archwires and auxillaries
- precision tooth movers
FA vs Removable
When do we use fixed appliances?
- 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
Andrew 6 Keys
- 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
Components of Fixed Appliances
- bracket/ tube
- archwires
- band
- modules
- auxillaries
- anchorage components
- force generating components
Brackets
Components
- bracket slot
- tie wings
- bracket base
Materials
- Metal SS, CoCr, Ti, Au
- Polymers
- Ceramics
Bands
- SS with pre-welded attachments
- require space before placement -> seperator visit
What does bracket prescription mean?
determines tip, torque, and in/out control
Bonding to teeth
- 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
Archwires
- SS**
- Nickel Titanium**
- CoCr
- Beta Titanium (TMA)
- composite/ glass
Why Nickel titanium arch wires?
- flexible
- light continuous force
- shape memory, can return to original shape, cannot bend
- higher friction than SS
SS
- working archwires
- slide teeth as low friction
- formable for archwire bends and loops
Force generating components
Sliding mechanism
- elastic power chain
- NiTi coils
- Intra- oral elastics
- active ligature
- teeth move by utilising energy stored in elastic/ spring
What is anchorage?
- resistance to unwanted teeth movement
- Newton 3rd law: every force has an equal but opp reactionary force
Simple anchorage
Compound anchorage
Reciprocal anchorage
Absolute anchorage
- Temporary anchorage devices (TADS)
- non- osseointegrating mini screws - Major development in orthodontics
- anchorage control
- tooth movement mechanics
Cortical anchorage
- cortical plates provide resistance to tooth movement
- maintains intermolar width
- nance palatal arch utilises palatal vault for anchorage reinforcement
Intermaxillary anchorage
Retainers
- for retention: maintaining final tooth position with passive orthodontic appliances
- prevent relapse; fixed/ removable
- must be stressed to pt at consent stage of tx lifelong retention
Features with high relapse potential
- diastema
- rotations
- palatally ectopic canines
- proclination of lower incisors
- anterior OB
- instanding upper lateral incisors
Removable retainers
- Pressure formed retainers
- 2 weeks full time wear except for eating and drinking
- and then night only after
- some clinicians will say straight to nights only
Hawley removable retainer
- labial bow to control incisors and canines
- not well tolerated in lower arch
Bonded wire retainer
- requires careful monitoring and ID cleaning
- ensure composite attachments intact and sound
- refer back to orthodontist if problems
Main risks of fixed appliances
- decalcification and caries
- relapse
- root resorption
Tx plan Pt Journey
- average case 18-24 months
- hypodontia 24-30 months
- orthognathic 24-30 months
Initial Problems encountered by pt
- pain
- mucosal irritation
- ulceration
- appliance breakage
Your role as GDP
- continue to see patient for routine and checkups
- reinforce OHI and diet advice
- liaise with orthodontist if concerns
- make appliances safe in case of orthodontic emergency
1. snipping of jaggy wire
2. removal of loose component
