Appliance design Flashcards
10 uses of casts
- Record treatment – mention outcome tx
- 3D representation of pt not there
- Design appliances
- Medical legal reasons
- Occlusions – assess for malocclusion
- get diagnosis
- treatment plan
- motivator – wax
- don’t want to good – want realistic expectations
- emphasise problems – more informed pt decision
- teaching
- forensics
- retrospective studies
aim of orthodontics
Functioning, aesthetics, stable occlusion
12 stainless steel properties
- malleable
- biocompatible
- doesn’t corrode
- non-toxic
- strong
- flexible
- resistant to abrasion
- high melting temperature
- elastomeric response – spring back into shape
- durable
- ductile
- cheap
5 components of stainless steel (and %)
72% Iron
18% Chromium
8% Nickel
- 7% Titanium
- 3% Carbon
URA
upper removable appliance

LRA
lower removable appliance
how do removable appliances working
move teeth
- tipping
- tilting
see saw effect
- around fulcrum – midpoint
move crown and root – not bending

advantages of removable appliances (9)
- tipping of teeth
- excellent anchorage
- generally cheaper than fixed – acrylic and SS – cheaper than fixed (bracket per tooth)
- LRA less tolerated – impinging on tongue space
- Shorter chairside time required
- Oral hygiene is easier to maintain – removable and clean them
- Non-destructive to tooth surface – no prep
- Composite bonds wire to teeth – need etch (destructive)
- Less specialised training needed to manage
- Can be easily adapted for overbite reduction
- How deep lowers coming up behind uppers
- Can be traumatic
- How deep lowers coming up behind uppers
- Can achieve block movements
disadvantages of removable appliances
- Less precise control of tooth movement
- only tipping/tilting, not lateral or intrusion/extrusion
- Can be easily removed by the pt
- Generally, only 1-2 teeth can be moved at a time (fixed can do multiple)
- Specialist technical staff required to construct the appliances
- check scope
- Rotations very difficult to correct – only small degree able to change
potential result due to crowding
common
- Rotated, overlapped, ectopic, PE anteriors due to lack of space
issues with overjet
horizontal
trauma, function, undesirable look, can get incompetent lips, lip trap (rest or infront of teeth)
how to create space in arch (2)

extract
widen arch - move teeth out
how to show extraction on design sheet

cross tooth out
common tooth to extract for ortho space creation
premolars
1st more – depends on angulation
- Cross out on design
what would the aim on URA design sheet be for
- anterior crowding + 6mm overjet
Aim - Please construct URA to retract 13 + 23
tell them what you want to achieve
retract
move distally
procline
push forward
retrocline
push back
notation used in appliance sheets
FDI in GDH
common to see palmer outwith
ARAB
- Active components
- Retentive
- Anchorage
- Baseplate
active component
- Part of moving teeth through application of force
active component for
- anterior crowding + 6mm overjet
13 and 23, palatal finger spread + guards, 0.5mm HSSW (hard, can get soft not in ortho)

why need to state gauge of wire on design sheet
- Direct relation to amount of force
- Thinner – lighter
- Thicker – greater
how to draw palatal finger spread (active component)
Round mesial aspect of tooth
Coil is where force exerted form
Retentive part
Guideplane





