REMOVEABLE ORTHO BASICS Flashcards
Components of stainless steel?
72% iron
18% chromium
8% nickel
1.7% titanium
.3% carbon
What movement can a removable orthodontic appliance do?
Tipping movements
How do teeth move via orthodontic appliances?
Constant and prolonged force applied
This leads to increased osteoclast activity on side away from force so bone resorbs allowing tooth to be moved, behind the tooth osteoblasts lay new Bone in the existing space.
(Bone remodelling)
Give some advantages of an upper removable appliance
Cheaper
Simple management - less chairside
Easier for pt to maintain oral hygiene
Less tooth prep
Give some cons of an URA
Relies on pt compliance
Only will tip or tilt a tooth
Only move 1-2 teeth a time
In what ways heat cure PMMA > self cure PMMA?
Heat cure is stronger and dimensionally stable
Heat cure only polymerise at certain heat due - increased working time
Heat burns off residual free radicals
If heat cure properties are better, why use self cure? In what case may you use heat cure?
Self cure takes 15 mins to set whereas heat cure process takes upwards to 13 hours
would use heat cure in individuals that are allergic to the monomer in self cure - as more free radicals
What are the active oral forces?
- mastication
- gravity
- speech
- tongue movements
- the active component
What mm wire is used for which areas?
Retentive = .7mm HSSW
Stops = .7mm HSSW
Active component = .5mm HSSW
Give the names of the different components of the adams clasp
Bridge
Arrowhead
S bend
Flyover
Leg
Tag
What is the acronym for contents of a RA?
A - active component
R - retention
A - anchorage
B - baseplate
What is the active component?
Component that exerts the prolonged force on the desired tooth
Usually a spring or screw
What is anchorage?
Resistance forces to unwanted tooth movement. Newton’s third law = equal and opposite reaction
Usually provided by baseplate as it dissipates forces
What function does the baseplate play?
Connects active component, clasps
Retention through adhesion and cohesion
