Ortho Lab

Question 1

in fixed orthodontics, what is the purpose of a ligature?

Answer 1

the hold the arch wire to the brackets

Question 2

in fixed orthodontics, what are ligatures made of?

Answer 2

either a tiny elastic or a twisted wire

Question 3

in fixed orthodontics, what is the purpose of the arch wire?

Answer 3

creates force to move teeth into proper alignment

Question 4

in fixed orthodontics, what is the purpose of brackets?

Answer 4

hold the arch wire in place- connected to the bands or directly bonded on the teeth

Question 5

in fixed orthodontics, what is a metal band?

Answer 5

a cemented ring of metal which wraps around the tooth

Question 6

in fixed orthodontics, what is the purpose of elastic hooks and rubber bands?

Answer 6

elastic hooks are used for the attachment of rubber bands, which help move teeth toward their final position

Question 7

name two types of retainers which may be given to a pt following fixed orthodontic treatment

Answer 7

thermoplastic retainer
bonded retainer

Question 8

name 3 uses of a transpalatal arch

Answer 8

anchorage
rotation
limited widening or contraction

Question 9

what is a transpalatal arch constructed from?

Answer 9

0.9mm hard stainless steel wire (HSSW)

Question 10

what teeth are a transpalatal arch most commonly attached to?

Answer 10

first permanent molars

Question 11

how is a transpalatal arch attached onto teeth?

Answer 11

with the use or stainless steel bands to which the appliance is spot weldered/ soldered on to

Question 12

what is a palatal arch with a nance button constructed from?

Answer 12

0.9mm hard stainless steel wire (HSSW)

Question 13

what teeth are a palatal arch with a nance button attached to?

Answer 13

first permanent molars

Question 14

how is a palatal arch with a nance button attached to teeth?

Answer 14

with the use of orthodontic stainless steel bands to which the appliance is attached to with the use of spot welding/soldering

Question 15

what is the main purpose of a palatal arch with a nance button?

Answer 15

anchorage

Question 16

what is a quadhelix constructed from?

Answer 16

0.9mm hard stainless steel wire (HSSW)

Question 17

what teeth are a quad helix usually attached to?

Answer 17

first permanent molars

Question 18

how is a quad helix attached to teeth?

Answer 18

with the use of orthodontic stainless steel bands to which the appliance is attached to with the use of spot welding/soldering

Question 19

what are the main uses of a quad helix?

Answer 19

bilateral expansion
asymmetrical expansion
fan style expansion
rotation of molars
expansion in cleft palate
modified to proline incisors
assist in habit breaking

Question 20

what are the advantages of fixed orthodontics?

Answer 20

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

Question 21

what are the disadvantages of fixed orthodontics?

Answer 21

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

Question 22

what are the advantages of removable orthodontics?

Answer 22

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

Question 23

what are the disadvantages of removable orthodontics?

Answer 23

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

Question 24

how does a transpalatal arch provide anchorage in fixed orthodontics?

Answer 24

it increases the root surface area and bone surface area

Question 25

give a disadvantage of a palatal arch with a nance button

Answer 25

it is very difficult to clean

Question 26

what does fan style expansion mean?

Answer 26

expanding the arch by moving posterior teeth only

Question 27

Name 3 types of retainers which can be used after fixed orthodontic treatment

Answer 27

-Hawley retainers Thermoplastic retainers Bonded retainers

Question 28

Give advantages if Hawley retainers

Answer 28

Most robust Can be removed for cleaning No Oreo of teeth required Incorporate all teeth Allow occlusal settling Can be slightly activated if required

Question 29

Give disadvantages of Hawley retainers

Answer 29

Bad aesthetics Hard to tolerate in both upper and lower Very time consuming to make

Question 30

Give advantages of thermoplastic retainers

Answer 30

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

Question 31

Give disadvantages of thermoplastic retainers

Answer 31

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

Question 32

Give advantages of bonded retainers

Answer 32

Invisible to other people Good for diastema’s and rotations Allows occlusal settling Unobtrusive- well tolerated Cheap Don’t rely on pt compliance

Question 33

Give disadvantages of bonded retainers

Answer 33

Required excellent OH High failure rate Etching is destructive Only inclusive of 6 anterior teeth

Question 34

what does IOTN stand for?

Answer 34

index of orthodontic treatment need

Question 35

what is the IOTN used for?

Answer 35

-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

Question 36

what are the 2 components of the IOTN?

Answer 36

aesthetic component dental health component

Question 37

what scores must a pt receive on the IOTN to receive NHS treatment?

Answer 37

DHC- 3+ AC-6+

Question 38

what does MOCDO stand for?

Answer 38

Missing teeth Overjets Crossbites Displacement of contact points Overbites

Question 39

what assumptions are applied during the DHC of the IOTN when casts are being used?

Answer 39

overjet- assume incompetent lips crossbite-assume discrepancy between RCP and ICP >2mm reverse overjet- assume speech problems

Question 40

name the 3 most common pliers used in the orthodontic lab

Answer 40

Adams 64 coil formers 65 wire cutters

Question 41

what does ARAB stand for?

Answer 41

active component retentive anchorage baseplate

Question 42

what are active components?

Answer 42

the components that will be moving the teeth with the application of force

Question 43

what is retention?

Answer 43

the resistance to displacement forces e.g. gravity, speech

Question 44

what is anchorage?

Answer 44

the resistance to unwanted tooth movement

Question 45

in a URA, what is the role of the baseplate?

Answer 45

-connects all components together as one unit -provides anchorage - assists with retention

Question 46

when would you use heat