orthodontics Flashcards

1
Q

what is IOTN?

A

index of orthodontic treatment need - measure impact of malocclusion on individuals dental health + psychosocial wellbeing

1 (least need) - 5 (greatest need)

dental health + aesthetic component

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2
Q

what is PAR?

A

peer assessment rating - quantitively measures malocclusion + efficacy of treatment

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3
Q

4 ways to modify growth

A
  1. functional appliance
  2. headgear
  3. temporary anchorage devices
  4. palatal implants
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4
Q

mode of action for removable appliances?

A

tipping

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5
Q

what is a flat anterior bite plane used for?

A

overbite reduction

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6
Q

what is an expansion appliance used for?

A

widen maxilla

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7
Q

what is a cover plate used for?

A

after exposure surgery - for 2 weeks

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8
Q

what is a space maintainer?

A

maintains space after early tooth loss for a prosthesis/successor

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9
Q

3 types of retainers post ortho

A
  1. essix
  2. hawley - full time 3/12 then nights
  3. fixed/bonded
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10
Q

what is a functional appliance?

A

removable or fixed using forces generated by stretching of muscles, fascia +/- periodontist to alter skeletal + dental relationships

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11
Q

what functional appliance is usually used for class II malocclusions?

A

twinblock

OJ>6mm

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12
Q

when is appropriate for use of functional appliance?

A

when actively growing

f = 11-13 years
m = 12-14 years
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13
Q

3 components of skeletal diagnosis

A
  1. classification
  2. FMPA
  3. Lower face height
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14
Q

what would an obtuse nasolabial angle suggest?

A

poor lip support - extractions to be avoided

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15
Q

measurements for mild, moderate + severe crowding?

A
mild = <4mm
moderate = 4-8mm
severe = >8mm
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16
Q

which cusps of molars normally occlude with each other?

A

upper buccal cusp, buccal to lower

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17
Q

risks of leaving impacted teeth?

A

cyst formation

root reosorption

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18
Q

risks of exposing impacted teeth?

A

root damage, crown damage, ankylosis

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19
Q

inevitable amount of induce inflammatory root resorption after orthodontic?

A

1-2mm

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20
Q

over what period of time for elastic recoil PDL fibres remodel?

A

~1y

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21
Q

4 main risk to explain when gaining consent for orthodontic treatment

A
  1. pain
  2. root resorption
  3. decalcification
  4. relapse/retention
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22
Q

examples of soft tissue/habits that change occlusal classfication

A
  1. lip trap = II
  2. large tongue = III
  3. active lowerlip = II
  4. digit sucking = II
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23
Q

movement made by fixed appliances?

A

bodily movement

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24
Q

what physics law does orthodontic anchorage use?

A

newtons 3rd law

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25
Q

6 ways to create space?

A
  1. leeway space
  2. distal movement
  3. arch expansion
  4. incisor proclamation
  5. inter proximal stripping
  6. extractions
26
Q

when should teeth be extracted?

A

1-2 weeks before appliance placement

27
Q

is GA justified for orthodontic extraction?

A

no

28
Q

a in IOTN

A

overjet

29
Q

h in IOTN

A

hypodontia

30
Q

I in IOTN

A

impedance

31
Q

m in IOTN

A

reverse overjet

32
Q

p in IOTN

A

clefts

33
Q

s in IOTN

A

submerged

34
Q

c in IOTN

A

crossbites

35
Q

d in IOTN

A

displacement

36
Q

e in IOTN

A

open bite

37
Q

factors affecting teeth resorption risk with fixed appliance

A
distance moved
existing resorption
pipette shaped roots/thin roots
previous trauma
asthma
38
Q

normal measurement for overbite

A

40%

39
Q

normal amount of incisor showing on smiling

A

75-100%

40
Q

how to describe overbite

A

% + complete/incomplete

41
Q

components of intra-oral ortho assessment

A
OH, periodontal status
incisor, canine, molar relationship
overjet + overbite
centreline discrepancies
crowding
cross bite/displacements
42
Q

reasons to take radiograph for ortho assessment

A

pathology suspected
skeletal discrepancies
developmental - uneurpted teeth/submerged/impacted

43
Q

aesthetic rating qualifying for NHS treatment

A

6 or above

44
Q

nemonic for order of IOTN

A

MOCDO

m=missing = h
o = overjet = a
c = cross bite = c
d = displacement = d
o = overbite
45
Q

which premolars extracted for severe crowding

A

4s

5s for less

46
Q

what is SNA

A

position of maxilla relative to anterior cranial base

47
Q

what is SNB

A

position of mandible relative to anterior cranial base

48
Q

what is ANB

A

relative position of maxilla to mandible

49
Q

benefits of ortho

A
function
relieve impaction  - resorption/cysts
reduce perio/caries
reduce trauma risk
psychological
50
Q

when should upper 6s be extracted?

A

8-10yrs

51
Q

when should lower 6s be extracted?

A

8-10yrs - 7s bifurcate 9/9.5

52
Q

biology of tooth movement

A

force applied, bone layed down where PDL under tension, resorbed in areas of PDL compression

53
Q

normal angle for nasolabial angle

A

90-110

54
Q

3 indications for taking lateral cephalogram

A

skeletal discrepancy
anterior-posterior movement of incisors is planed
monitoring of growth

55
Q

3 options for skeletal problems

A

orthodontic camouflage
growth modification
surgery

56
Q

when might you retain poor prognosis 6s

A

retain until 7s erupted if severe overjet or anterior crowding - space maintenance

57
Q

what is vertical subsigmoid osteotomy used to achieve?

A

setback on mandible

58
Q

what is a sagittal split osteotomy used to achieve?

A

advance or pushback mandible or asymmetry

IAN complication
most common surgery

59
Q

most common maxillary surgery

A

le fort 1 osteotomy

60
Q

orthodontic treatment done before orthographic surgery is called what

A

decompensation - may make worse to start with

61
Q

prevalence of cleft lip/palate

A

1/700 Caucasians

62
Q

syndrome often associated with cleft lip/palate

A

treacher collins