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
Lingual appliance problems
Difficult technique Cost Traumatic to tongue
26
Lower molar bands - parts
Single tube for archwire | Hook for aux wires
27
Upper molar bands - parts
Additional tube for headgear | Hook for aux
28
Why are separators placed for molarbands
More comfortable Easier More accurate band selection
29
Directly bonded molar tubes - disadvantages
Difficult moisture isolation Problem with wire if debonds Can't use with headgear
30
Archwire function and mechanism
Active - move teeth with wire | Passive - move teeth along wire
31
Active wires - material | Passive wires - material
NiTi - | SS - bodily movement
32
Auxiliary components
Elastics and springs
33
Weingarts
Gripping archwires
34
Tucker
tucking ends of quickties
35
Adam's pliers
Making bends
36
Light wire plier cutters
Cutting light wires
37
Crown shears
Cutting ends of quickties
38
Distal end cutters
Cutting end of archwires in mouth
39
What do modules do IO elastics? Transpalatal archwire/quadhelix?
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