Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Orthodontics (IODC) > Removable appliances in orthodontics > Flashcards

Removable appliances in orthodontics Flashcards

1
Q

42% of removable appliance cases in GP

A

Showed “no improvement” (as measured by the PAR index)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Advantage

A

Removable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Distadvantage

A

• It’s removable! – not in the mouth – not
working, can be lost/ damaged…
• Can only tip teeth
• Affects speech
• Poorly tolerated in lower arch
• Intermaxillary traction not possible
• Inefficient for multiple tooth movements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

One-point contact at tooth crown

A

Can only tip teeth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Fully controlled movement

A

Need attachment to tooth

-full 3D control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Designing a removable appliance

A

Keep
It
Simple
Stupid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Components (ARAB)/ Design

A
  • Active components - how to move teeth
  • Retention – stop it falling out
  • Anchorage – stop the wrong teeth moving
  • Baseplate and Biteplanes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Active components: moving teeth with removable appliances

A 
Springs
-palatal springs
-(buccal springs)
Screws
Elastics
*decreasing order of preference*
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Properties of springs

A

Force of spring depends on

  • thickness of wire
  • length of wire
  • amount of deflection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Length of wire

A

Force is proportional to (1/length^3)

Coil near acrylic increases length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Thickness of wire

A

Force is propertional to diameter ^4

Use 0.5-0.6mm diameter wire for active components

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Z-spring

A

Incisor spring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

T-spring

A

Longer so exerts less force and given space for expansion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Palatal finger spring

A 
0.5-0.6mm sire
Coil near acrylic (increases length)
Coil on side away from direction of movement
Can use any teeth
-not good on buccally placed teeth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Screws

A

Closed or open

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Adjustment of screws

A

Quarter turn = 0.2mm
1 turn per week = just <1mm per month
2 turn per week = just <2mm per month

17
Q

Indications for screws

A

Moving blocks of teeth

Can move tooth and use for retention

18
Q

Screws

A

Moving upper labial segment

19
Q

Orthodontic elastics

A

Poor control

Rarely used

20
Q

Posterior retention - Adams cribs

A

MB and DB undercuts

Only need undercut of 0.25mm

21
Q

Anterior retention

A

Due to inclination there will be a downward vector
C-clasp
Southend clasp

22
Q

Anchorage

A

The control of unwanted tooth movement
Newton’s 3rd law of motion
-to every action is an equal and opposite reaction
25g-30g on canines ideal force

23
Q

How not to lose anchorage

A
  • Light forces
  • Only move one tooth per side
  • Large anchor unit
  • more teeth included in appliance design
  • Headgear?
24
Q

Problems with headgear

A

Co-operation
Safety
-pts were actually wearing 6.5 hours instead of 12 hours

25
Q

Headgear safety

A

Catapulting accident

Night-time dismantling

26
Q

Problems of eye injury

A 
Hihg risk of infection
Excellent culture medium
Difficult to control with antibiotics
Sympathetic ophthalmitis
-safety mechanisms essential
27
Q

Baseplate

A
  • Connects components
  • Carries passive wirework
  • Additional anchorage
  • Carries biteplanes
28
Q

Biteplanes

A

Anterior biteplane
• Flat
• Inclined
Posterior biteplane

29
Q

Flat anterior bite plane

A

Reduces overbite

30
Q

Inclined bite plane

A

Post functional appliances

Anterior: to retain functional appliance treatment, proclines lower incisors (unfortunately)

31
Q

Posterior biteplane

A

Free occlusion

32
Q

Cases to treat with removable appliances

A 
• Disimpaction of first molars
• Class III - Anterior crossbite
• Posterior crossbite (with associated
mandibular displacement) in mixed
dentition or expansion prior to
functional appliances
• Space maintenance
• (Overbite correction)
33
Q

Adjusting Adams Cribs

A

Gently roll arrowhead in or out with pliers

34
Q

Z-spring adjustment

A

Pull forwards and upwards, away from baseplate

35
Q

Fitting of a URA

A
  • Check lab ticket
  • Explain how the appliance works
  • Try-in
  • Adjust retentive components if required
  • Activate
  • Adjust bulky biteplanes if appropriate
  • Demonstrate then check pt can fit and remove
  • Instructions when to wear, how to clean etc
  • Document everything you have done
36
Q

Visit by visit assessment

A
  • Talk to patient (and parent)
  • Assess for signs of wear
  • Assess progress, measure changes
  • Assess OH
  • Assess retention
  • Check if active component is active
  • Reassess anchorage
  • Document findings and plan
37
Q

Which spring is the preferred method of reducing overjet?

A

Robert’s retractor

Orthodontics (IODC) (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions