Ortho Lab Flashcards
what are advantages of a fixed appliance
can carry out 3d movement of the tooth
can correct rotations
can utilise bodily movement and torque
compliance is not an issue as it cannot be removed by the patient
less intrusive on tongue space
minimal palatal coverage
can move multiple teeth
what are disadvantages of a fixed appliance
oral hygiene must be good and it is made more difficult
risk of decal
risk of root resorption
no intrinsic anchorage
can cause soft tissue trauma
poor aesthetics
cost
when would a fixed appliance be used
to correct mild to moderate skeletal discrepancies - camouflage
to correct rotations, spaces, intrusion and extrusion
what are the components of a fixed appliance
archwire
bracket
ligature
bands
hooks and elastics
force generating components - spring coils
what is the function of the archwire
the wire contains the prescription, it has shape memory. when put through the brackets, the shape is distorted, so carries out a force on the teeth whilst trying to obtain its original shape
what is the function of the bracket
the interface between the tooth and the archwire, transmits force from wire to tooth. bonded to tooth with etch, bond and composite
what is the function of the ligature
to hold the archwire in place on the bracket, can be elastic or twisted module
give some examples of how anchorage can be achieved with fixed appliance
temporary anchorage device - non-osseointegrating mini screws in palate
transpalatal arch
transpalatal arch with nance button
baseplate
what are the advantages of URA
tipping of teeth, good for correction of overbite, removable so good for OH, cheaper than fixed, shorter chairside time, less specialist training, good anchorage
what are the disadvantages of URA
removable - poor compliance
can only move one or two teeth
not good for rotations
less precise tooth movement
requires technical staff
what are the uses of ura
tipping of teeth, reduce OB, habit breaker, retainer, expand arch
what are the uses of study casts
diagnosis
treatment planning
monitoring treatment
designing appliance
discussing and explaining to patient
teaching
what are the components of stainless steel
72% iron
18% chromium
1.7% nickel
0.3% carbon
what are displacement forces
mastication, speech, tongue, gravity, active component
what components make up a URA
active component, retention, baseplate