Fixed Appliances Flashcards
definition of fixed appliance
appliance which is fixed to teeth and cannot be removed by patient
consists of brackets, bands, arch wires and auxillaries
features/pros/cons of fixed appliances
Pros:
3D control
Complex tooth movements
Control of root
Less dependant on
compliance
cons:
Requires excellent oral
hygiene
Risk of iatrogenic damage
Poor intrinsic anchorage
features/pros/cons of removable appliances
simple tooth movements - tipping/tilting
pros:
- less risk of iatrogenic damage
- good intrinsic anchorage
cons:
- greater compliance required
no control over root movement
- can be lost
when do we use fixed appliances?
- correction of mild to moderate skeletal discrepancies
- alignment of teeth
- correction of rotations
- centreline correction
- overbite and overjet reduction
- closure of spaces/creating space
- vertical tooth movement
list andrews 6 keys
- tight approximal contacts with no rotations
- class 1 incisors
- class 1 molars
- flat occlusal plane or slight curve of spee
- long axis of the teeth have a slight mesial inclination (except lower incisors)
- crowns of canines back to molars have a slight lingual inclination
list fixed appliance components
- bracket/tube
- band
- arch wire
- modules
- auxiliaries
- anchorage components
- force generating components
what components make up a bracket?
- bracket slot
- tie wings
- bracket base
what materials used to make brackets?
- metal: SS, CoCr, Ti, Au
- polymers
- ceramics
What are bands? (in fixed appliances)
SS with pre welded attachments
- tubes or cleats
- require space before placement (separator visit)
what factors are determined by bracket prescription?
- tipping movement
- torque
- in/out control
what materials used for bonding to teeth with fixed appliances?
- composite, acid etch
used for brackets and tubes - GI used for molar bands
most common materials used for arch wires?
- SS, NiTi
Features of NiTi used in arch wire
- flexible
- applies light continuous force
- shape memory (returns to original shape, cannot bend)
- higher friction than SS
features of SS arch wire
- low friction
- formable:
can make arch wire bends and loops
list force generating components in fixed appliances
- sliding mechanics:
elastic power chain
NiTi coils
intraoral elastics
active ligature - teeth move by utilising the energy stored in elastic or spring
what is this?
elastomeric chain
what is this?
NiTi coil springs
what is this?
intraoral elastics
what type of anchorage is shown here?
simple
what type of anchorage is shown here?
compound
what type of anchorage is shown here?
reciprocal
what kind of device is used for absolute anchorage?
- temporary anchorage device (TADS):
non osseointegrating mini screw - major development in orthodontics:
anchorage control
tooth movement mechanics
what temporary anchorage devices (TAD) are shown here?
(left) inter-radicular TAD
(right) palatal TAD
what is cortical anchorage?
- cortical plates provide greater resistance to unwanted tooth movement
- maintains intermolar width
what type of anchorage is shown here?
inter maxillary anchorage
list some types of removable retainers + features
- pressure formed retainers
- (clear overlay retainers):
variety of materials and thickness
can include prosthetic tooth for aesthetics
well tolerated
what retainer is this and how does it work?
- Hawley retainer
- labial bow to control incisors and canines
- not well tolerated in the lower arch
in what clinical situations are fixed orthodontic retainers used?
- space closure
- diastema
- proclination of lower labial segment
- periodontal cases
- ectopic canines
- instanding upper 2’s
- some orthodontists use them for all cases
important things to know for bonded wire retainers?
- requires careful monitoring and ID cleaning
- ensure composite attachments intact and sound
- refer back to orthodontist if problems
risk/benefits of fixed appliances
- decalcification
- root resorption
- relapse
- enamel wear
