Contemporary orthodontics Flashcards
what are the 3 different types of appliances?
- growth modification - aim to alter growth
- move teeth within existing bony envelope eg. fixed appliances and removable appliances
- retainers
what do we want from appliances ?
we want the best possible outcome
1. appearance
2. function
3. health
what are some other things we want
- comfortable tx
- acceptable appearance during tx
- acceptable tx time
- lowest possible risk during tx
- long term stability
which 2 appliances aim to improve class 2 dental and skeletal relationship?
- functional appliances
- headgear
when is the best time to use class 2 appliances?
11-14 yrs pubertal growth
*can use earlier if bullying or high risk of dental trauma
what are the different types of functional appliances?
- REMOVEABLE
- TWIN BLOCK
- MEDIUM OEPNEING ACTIVATOR
- FIXED
describe removable appliances?
wear for 22hrs a day, remove for eating cleaning and sport
describe twin block appliances
2 pieces that touch together to force pt to bite forward
describe the medium opening activator?
single piece that pt bites into
list all of the different types of removable appliances ?
twin block
medium opening activator
describe the fixed functional appliances
attaches from an upper molar to a lower tooth
piston arms force pt to bite forward
how do all functional appliances work?
by forcing pt to bite forward and that causes muscle to stretch which transmits forces on bones and teeth.
- correct AP relationship and vertical relationship in pts with deep bites
are functional appliances effective?
yes if pt is growing and compliant
what are the dental changes that can happen with functional appliances?
- procline lower incisors
- retrocline upper incisors
- change molar relationship from c2 to c1
what else can functional appliances do to occlusion?
can also correct deep bite
- act as a bite plane to promote molar eruption
list the benefits of functional appliances?
- correct C2 malocclusion =overjet and molar relationship
- can have vertical effects
- small improvement in facial appearance- best if pt has low angle (reduced vertical height) and C2
- can be used with fixed appliances
what are the risks with functional appliances?
- high failure risk of non-compliance
- can impact quality of speech, eating discomfort (due to stretching of muscle), need to take out for sport
what is another appliances which aims to improve C2?
headgear
describe headgears?
- 14hrs per day
- all the time including sleeping except for school and eating and sport
- u can put the force in different directions
- worn for 6-9 months(so as soon as they stop wearing it normal growth will restart)
are headgears effective?
- yes if pt is growing and compliant
what are the dental changes in headgears?
- retract molars from C2 to C1 (may also intrude if there is anterior open bite )
- reduce overjet by retroclining upper incisors
do headgears provide growth change?
- very little evidence of sustained change in growth
how can headgears be used to correct anterior open bite?
can reduce vertical proportions by;
1. intrude maxillary molars
2. restrain maxilla
3. mandible rotates and front teeth close together
what are the benefits of headgears?
- correct C2 malocclusions = overjet and molar relationships
- little change to facial appearance - better than functional appliances if pts have increased vertical proportions
- can be used with fixed appliances
what are the risks of headgears?
what are the aims of C3 growth modifications ?
- promote maxillary growth
- restrict mandibular growth
- combination of the 2
when do we use C3 modifications?
8-10 yrs
what are the 3 different appliances and which one do we use in the uk?
- UK= protraction face mask
- reverse functional
- chin cap
describe the protraction face
- sits on chin and forehead
- elastics to fixed/ removable maxillary appliances
- pulls maxilla forward using frame as anchorage - promotes maxillary growth
- 14hr per day
- most effective at 8-10 yrs
what are the benefits of protraction face mask?
what are the risks of protraction face masks ?
describe the reverse functional?
aims to push mandible back and maxilla forward
mostly vertical change no AP
- very bulky and difficult to wear
describe chin cap
what is the aim with transverse change?
to correct interarch transverse relationship
- do this by expanding maxilla to correct buccal crossbite
what is rapid maxillary expansion?
- need to do it before mid palatal suture has fused 14-15 yrs
- fit appliance then open screw approx 0.5mm/day for 1-2 weeks
- need to hold for 3 months while bone fills in
what are the benefits of rapid maxillary expansion?
- correct buccal crossbite
- create space for aligning teeth (due to crowding)
- widen buccal corridors - better aesthetics
what are the risks of rapid maxillary expansions?
what are the aims of fixed appliances?
correct malocclusions by repositioning teeth within existing bony envelope
they dont significantly alter face shape or soft tissues
- teeth have to be within alveolar bone in order for them to move
what are the different stages of fixed appliances?
- align = straighten them up (my need to extract to get space)
- level = reduced deep bites or AOB = make sure arches are flat
- correct inter-arch relationship (how teeth bite together) = that could be AP (mild C2 or C3), or correcting transverse (crossbite) or correcting vertical (which usually corrected in levelling stage
- close spaces = can be as result of extraction
- root/ crown positioning= allow teeth be paralell
how do we categorise the different types of fixed appliances?
what are the basic principles of fixed appliances ?
- 3D control
- alter force
- bracket and wire enable force to be transmitted to tooth
- bracket design and material has little impact
what does the bracket slot determine?
determines which wire is needed
- wire size, shape and material are important
explain the order of wires we use?
- SMALL ROUND wire = very elastic = not too much force= starts to align teeth = fits loosely into slot
- once teeth start to align we use = BIGGER ROUND wire= fits slot more
- then we use RECTANGULAR wire= which actually fit = gives 3D control
what are the benefits of fixed appliances?
what are the risks of fixed appliances ?
what can we use alongside fixed appliances?
adjunctive appliances :
1. quad helix
2. trans palatal
describe quad helix?
- used to expand maxillary arch
- dental change only
-used for less severe crossbite
describe trans palatal arch?
- support anchorage
- don’t move teeth but hold teeth while we use fixed appliances to move teeth around
what are temporary anchor devices?
- aka mini screws
- like implants They don’t Osseo integrate so can remove
- can be screwed in buccal or palatal bone
- provide point for force application eg. support anchorage
- lots of applications
what are the aims of removable orthodontic appliances ?
- correct malocclusion by repositioning teeth within existing bony envelope therefore don’t correct C2 or C3 skeletal relationships
- don’t significantly change face shape or soft tissues
- limited tooth movement
- usually adjunctive appliances
how is tooth movement achieved with removable orthodontic appliances?
- active wire components (URA, barre)
- thermoplastic material (aligners)
describe traditional URA?
A= active component (z springs at front)= aim to push teeth forward
R= retention (clasp on molars) to hold appliance in place
A= anchorage = to stop rest of teeth moving forward
B = base plates
*some components can do more than pone thing
benefits and risks of URA’s
*interceptive devices= can add false teeth on them
describe Barre appliances
- don’t do anything for back teeth or change the bite
risks and benefits of barre
- big and bulky
how do thermoplastic appliances work?
- eg. Invisalign
- move teeth up to 0.2mm per aligner
- photos, impressions and radiographs taken
- you have composite attachments too which allow thermoplastic material to grip on to and give force onto teeth
benefits and risks of thermoplastic appliances
what are the aims for retainers
resist relapse by holding teeth in new position
what can retainers be categorised into?
- removable
- fixed
what are the different types of removable retainers ?
- vaccum formed (essix) = clear plastic, look like aligners (cant eat with them)
- hawley= hard based plate with metal to hold teeth in place (benefit of hawly is that you can attach teeth so can use as a temp measuere if they have lost a tooth almost like a denture (can eat with them )
what are the different types of fixed retainers?
- direct or indirect= can be made chairside or in lab
- type of material
- design and material = can be put on only couple teeth
what are the disadvantages to fixed retainers ?
- can fail esp placed in upper arch and you have heavy occlusion = fracture
- over time = fatigue
why is retention so important ?
