Ortho Lab Flashcards
in fixed orthodontics, what is the purpose of a ligature?
the hold the arch wire to the brackets
in fixed orthodontics, what are ligatures made of?
either a tiny elastic or a twisted wire
in fixed orthodontics, what is the purpose of the arch wire?
creates force to move teeth into proper alignment
in fixed orthodontics, what is the purpose of brackets?
hold the arch wire in place- connected to the bands or directly bonded on the teeth
in fixed orthodontics, what is a metal band?
a cemented ring of metal which wraps around the tooth
in fixed orthodontics, what is the purpose of elastic hooks and rubber bands?
elastic hooks are used for the attachment of rubber bands, which help move teeth toward their final position
name two types of retainers which may be given to a pt following fixed orthodontic treatment
thermoplastic retainer
bonded retainer
name 3 uses of a transpalatal arch
anchorage
rotation
limited widening or contraction
what is a transpalatal arch constructed from?
0.9mm hard stainless steel wire (HSSW)
what teeth are a transpalatal arch most commonly attached to?
first permanent molars
how is a transpalatal arch attached onto teeth?
with the use or stainless steel bands to which the appliance is spot weldered/ soldered on to
what is a palatal arch with a nance button constructed from?
0.9mm hard stainless steel wire (HSSW)
what teeth are a palatal arch with a nance button attached to?
first permanent molars
how is a palatal arch with a nance button attached to teeth?
with the use of orthodontic stainless steel bands to which the appliance is attached to with the use of spot welding/soldering
what is the main purpose of a palatal arch with a nance button?
anchorage
what is a quadhelix constructed from?
0.9mm hard stainless steel wire (HSSW)
what teeth are a quad helix usually attached to?
first permanent molars
how is a quad helix attached to teeth?
with the use of orthodontic stainless steel bands to which the appliance is attached to with the use of spot welding/soldering
what are the main uses of a quad helix?
bilateral expansion
asymmetrical expansion
fan style expansion
rotation of molars
expansion in cleft palate
modified to proline incisors
assist in habit breaking
what are the advantages of fixed orthodontics?
Bodily tooth movement
Rotations easily fixed
Can be used easily in the lower arch as well as the upper
Individual force can be applied to every tooth
Not easily removed by the patient
Works 24 hours/7 days a week
Precise 3D movement of teeth
Less invasive of tongue space
Minimal palatal coverage
what are the disadvantages of fixed orthodontics?
Increased risk of root resorption
Decalcification
Can be perceived as visually unattractive
Can cause soft tissue trauma
Cost
High motivation in regards to oral hygiene
Poor anchorage
Highly trained specialist training
Etching is a destructive procedure
what are the advantages of removable orthodontics?
Tipping of teeth
Excellent anchorage
Generally cheaper than fixed
Shorter chairside time required
Oral hygiene is easier to maintain
Non-destructive to tooth surface
Less specialised training required to manage
Can be easily adapted for overbite reduction
Can achieve block movements
what are the disadvantages of removable orthodontics?
Less precise control of tooth movement
Can be easily removed by the patient
Generally only 1-2 teeth can be moved at one time
Specialist technical staff required to construct the appliances
Rotations very difficult to correct
how does a transpalatal arch provide anchorage in fixed orthodontics?
it increases the root surface area and bone surface area
give a disadvantage of a palatal arch with a nance button
it is very difficult to clean
what does fan style expansion mean?
expanding the arch by moving posterior teeth only
Name 3 types of retainers which can be used after fixed orthodontic treatment
-Hawley retainers
Thermoplastic retainers
Bonded retainers
Give advantages if Hawley retainers
Most robust
Can be removed for cleaning
No Oreo of teeth required
Incorporate all teeth
Allow occlusal settling
Can be slightly activated if required
Give disadvantages of Hawley retainers
Bad aesthetics
Hard to tolerate in both upper and lower
Very time consuming to make
Give advantages of thermoplastic retainers
Good aesthetics
Easily replaced
Incorporate all teeth
Can be removed for cleaning
Well tolerated
Can induce a small amount of force if pt forgets to wear them for a while
Give disadvantages of thermoplastic retainers
Plasticiser disforms over time
No occlusal settling
Easily lost
Some pts boil them to sterilise
Toothpaste is abrasive
Pts try use them to bleach teeth
Give advantages of bonded retainers
Invisible to other people
Good for diastema’s and rotations
Allows occlusal settling
Unobtrusive- well tolerated
Cheap
Don’t rely on pt compliance
Give disadvantages of bonded retainers
Required excellent OH
High failure rate
Etching is destructive
Only inclusive of 6 anterior teeth
what does IOTN stand for?
index of orthodontic treatment need
what is the IOTN used for?
-to assist in determining the potential impact of a malocclusion on an individual’s dental health and their psychosocial well-being
-used by NHS to assess eligibility to receive NHS treatment
what are the 2 components of the IOTN?
aesthetic component
dental health component
what scores must a pt receive on the IOTN to receive NHS treatment?
DHC- 3+
AC-6+
what does MOCDO stand for?
Missing teeth
Overjets
Crossbites
Displacement of contact points
Overbites
what assumptions are applied during the DHC of the IOTN when casts are being used?
overjet- assume incompetent lips
crossbite-assume discrepancy between RCP and ICP >2mm
reverse overjet- assume speech problems
name the 3 most common pliers used in the orthodontic lab
Adams 64
coil formers 65
wire cutters
what does ARAB stand for?
active component
retentive
anchorage
baseplate
what are active components?
the components that will be moving the teeth with the application of force
what is retention?
the resistance to displacement forces e.g. gravity, speech
what is anchorage?
the resistance to unwanted tooth movement
in a URA, what is the role of the baseplate?
-connects all components together as one unit
-provides anchorage
- assists with retention
when would you use heat
