Fixed appliances in Orthodontics I: Theory and Components Flashcards

1
Q

Indications for FA

A

Correct overjet/overbite
Correct mild/mod skeletal discrepancy
Space closure
Rotation

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2
Q

Why can it induce greater range of movement?

A

They are attached but less effective at moving blocks of teeth

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3
Q

What are the brackets attached to and how do they work?

What do they allow for?

A

Bracket attached to surface allows for vertical and tilting movement. Force couple generated from interaction between bracket and archwire running through it (rotational and apical movements)

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4
Q

Types of tooth movement possible?

A
Tipping
Bodily movement
Rotation 
Torque
Vertical movements
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5
Q

Removable appliances can only?

A

Tip

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6
Q

What determines type and direction of movement?

A

Interaction between bracket and wire determines type and direction of movement. Shape of bracket affects movement. Rectangular usually. Narrow bracket allow for greater archwire span therefore more flexibility. Wider reduces interbracket archwire span (reduced flexibility but more useful for derotation and MD control).

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7
Q

What does narrow bracket allow for? Wider bracket = ?

A

Greater archwire span so more flexibility

Reduced archwire span but more MD control

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8
Q

Greater control is gained by?

A

More similar fit of archwire in bracket

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9
Q

Round wire in rectangular slot?

A

MD tilt, vertical height and rotational position control

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10
Q

Round wire used for

A

only BL tipping and initial alignment

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11
Q

Rectangular - Rectangular slot

A

BL apical movements and premature tipping before slot is reached
Final alignment and space closure

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12
Q

Most common?

A

Fixed appliance with rectangular wires achieves movements in all 3 planes

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13
Q

First order wire bend

A

Made in plane of archwire

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14
Q

Second order

A

Vertical plane to achieve MD changes

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15
Q

Third order - work for? and do?

A

work for rectangular wires - twist plane of wire to create buccolingual apical force = TORQUE

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16
Q

How can amount of force applied to tooth be changed

A

Can be controlled by varying cross sectional diameter and form of archwire

17
Q

Problems with fixed appliances

A
Enamel demineralisation 
Root resorption 
Soft tissue lacerations
Perio 
Unwanted movement 
Pulp devitalisation
18
Q

What can FA achieve

and how

A

Tooth alignment in all three planes - rotation, torque and tip control
Space closure - bodily movement

19
Q

Components of FA

A

Brackets
Molar tubes/bands
Archwires
Auxiliaries

20
Q

Bracket materials

A

Metal - SS

Ceramic - plastic

21
Q

Aesthetic bracket materials

A

Ceramic
Lingual SS
Plastic

22
Q

Problems with plastic brackets

A

Fracture
Distortion
Discolouration

23
Q

Problems with ceramic brackets

A

Fracture
Abrasion of other teeth
Increased friction
Cost

24
Q

Ceramic use

A

Only in upper arch

Only in lower if no overbite

25
Q

Lingual appliance problems

A

Difficult technique
Cost
Traumatic to tongue

26
Q

Lower molar bands - parts

A

Single tube for archwire

Hook for aux wires

27
Q

Upper molar bands - parts

A

Additional tube for headgear

Hook for aux

28
Q

Why are separators placed for molarbands

A

More comfortable
Easier
More accurate band selection

29
Q

Directly bonded molar tubes - disadvantages

A

Difficult moisture isolation
Problem with wire if debonds
Can’t use with headgear

30
Q

Archwire function and mechanism

A

Active - move teeth with wire

Passive - move teeth along wire

31
Q

Active wires - material

Passive wires - material

A

NiTi -

SS - bodily movement

32
Q

Auxiliary components

A

Elastics and springs

33
Q

Weingarts

A

Gripping archwires

34
Q

Tucker

A

tucking ends of quickties

35
Q

Adam’s pliers

A

Making bends

36
Q

Light wire plier cutters

A

Cutting light wires

37
Q

Crown shears

A

Cutting ends of quickties

38
Q

Distal end cutters

A

Cutting end of archwires in mouth

39
Q

What do modules do

IO elastics?

Transpalatal archwire/quadhelix?

A

Secure archwire in archwire slot/ wire ligatures which are easier to tighten
Intra oral elastics used for traction - should be changed every day

Palatal/lingual arches can be placed in a quad helix fashion to provide extra anchorage for expansion e.g - made in lab from impression of teeth with bands on. bands then removed and placed into impression