Fixed appliances in orthodontics theory and components

Question 1

Type of tooth movement

Answer 1

Tipping
•Bodily movement
• Rotation
•Torque
•Vertical movements
-extrusion
-intrusion
(removable appliances can only tip)

Question 2

Problems with fixed appliances

Answer 2

• Enamel demineralisation/caries
• Root resorption
• Periodontal problems
• Unwanted tooth movements
• Pulp devitalisation
• Soft tissue lacerations
• Allergies

Question 3

Periodontal problems

Answer 3

Gingivitis
Gingival hyperplasia
-due to plaque build up because it is harder to maintain oral hygiene

Question 4

Fixed appliances

Answer 4

• Good tooth alignment
-corrects rotations
-controlled tipping
-torque control
• Good space closure (bodily movement)

Question 5

Fixed appliance components

Answer 5

Brackets
Molar tubes/ bands
Archwires
Auxiliaries

Question 6

Brackets

Answer 6

Pre-adjusted edgewise brackets (stainless steel)

• tie wings
• slot
• bracket slot size is 0.022”x 0.028”

Question 7

Round archwire

Answer 7

Initial tooth alignment

0.014

Question 8

Rectangular archwire

Answer 8

Full 3 control
0.019” x 0.025”
Space closure and final alignment
-better control over tooth movement

Question 9

Bracket materials

Answer 9

Metal - stainless steel
(Plastic)
Ceramic
(Gold)

Question 10

Bracket base

Answer 10

Foil-mesh
-increase surface area and retention
Etch tooth (self-etching primer) and use composite to bond it on
Light cure once bracket is on

Question 11

Bracket placement

Answer 11

Middle of tooth

Question 12

Aesthetic brackets

Answer 12

Plastic
Ceramic
Lingual (SS)

Question 13

Plastic brackets - problems

Answer 13

Fracture
Distortion (creep)
Discolouration

Question 14

Ceramic bracket - problems

Answer 14

Fracture
-in use
-debonding
Abrasion of other teeth
Increased friction
Cost

Question 15

Ceramics

Answer 15

Use in upper arch only

Can be used in lower arch if there is no overbite

Question 16

Lingual appliances

Answer 16

Difficult technique
Cost
Traumatic to tongue

Question 17

Lower molar bands

Answer 17

Single tube for archwire

Hook for auxiliaries

Question 18

Upper molar bands

Answer 18

Additional tube for headgear (round) - do not use for A/W
Hook for auxiliaries
32 sizes for each tooth

Question 19

Separators

Answer 19

A week before they have their bands fitted
1 week
More comfortable for px
Easier for operator
More accurate band selection
-can be painful for teenagers

Question 20

Molar tubes - direct bond

Answer 20

Difficult isolation from moisture - more likely to debond
Problem with wire if debonds
Can’t use with headgear

Question 21

Archwires - function

Answer 21

Active archwires - move teeth with wire
-light forces
-flexible
Passive archwires - move teeth along wire
-rigid

Question 22

Active archwires

Answer 22

Nickel-titanium (for alignment)

• super-elastic
• heat-activated

Question 23

Passive archwires

Answer 23

Stainless steel (for bodily movement of teeth)
-need to use something else e.g. auxiliary to move teeth

Question 24

Stainless steel - elastic properties

Answer 24

Hooke’s law

Very little elastic deformation

Question 25

Nickel titanium elastic properties

Answer 25

Superelastic properties

Question 26

Archwires - cross-section

Answer 26

Round 0.01"x0.02 | Rectangular wire 0.019"x0.025"

Question 27

Attaching archwire

Answer 27

``` Elastic modules Wire ligatures (quick ties) Self ligating brackets -less friction on bracket (now been disproven) -trap door ```

Question 28

Auxiliaries

Answer 28

Elastics | Springs

Question 29

Elastics

Answer 29

``` Elastic bands Powerchain Zing string (powerthread) E-links Traction ligatures ```

Question 30

Traction ligature

Answer 30

Module on a SS ligature

Question 31

Elastics

Answer 31

Worn between top and bottom teeth | Named by malocclusion we are trying to correct

Question 32

Power chain

Answer 32

Elastic chain in between the teeth Put quick ties on first, powerchain on top Occasionally used across spaces

Question 33

Zing string

Answer 33

Elastic thread | Trying to pull a tooth more gently

Question 34

E-links

Answer 34

TP orthodontics Not used as much Close space, like powerchain but long elastic above tooth

Question 35

Springs

Answer 35

``` Push coil/ coil spring -stainless steel -nickel-titanium Closing coil/ retraction springs -nickel-titanium ```

Question 36

Fixed appliances kit

Answer 36

Weingarts for gripping archwires Tucker for tucking ends of quickties Adams pliers for making bends in archwires or adjusting clasps on removable appliances Light wire pliers/ cutters for cutting lights wires/ elastic Crown shears for cutting ends of quickties Distal end cutters for cutting end of archwires

Question 37

Invisalign

Answer 37

Increasingly popular Not on NHS Can't move teeth as much Around 4.5k

Question 38

What are the ways to manage anchorage with fixed appliances?

Answer 38

``` Only move one tooth per side Headgear Class II elastics Transpalatal arches Extend base plate of upper removable appliances Use large anchor unit Light forces Extraction of teeth ```