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BDS4 CDS Ortho > Class II div 1 > Flashcards

Class II div 1 Flashcards

1
Q

defintion class II div 1

BSI

A

The lower incisor edges lie posterior to the cingulum plateau of the upper incisors

There is an increased overjet

The upper central incisors are proclined or of average inclination

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2
Q

most common form of malocclusion

A

class II div1

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3
Q

why tx pt who has class II div 1 malocclusion/

2

A

concerns re aesthetics

concerns re dental health
* prominent incisors at risk of trauma esp if incompetent lips

overjet >9mm
* twice as likely to suffer trauma
* IOTN 5a

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4
Q

overjet >9mm
concerns

2

A
  • twice as likely to suffer trauma
  • IOTN 5a
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5
Q

aetiology of class II div1

4

A
  • skeletal pattern - A/P, vertical, transverse
  • soft tissues
  • dental factors
  • habits
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6
Q

A/P skeletal pattern for class II div 1

A

Usually associated with Class II skeletal pattern

Commonly due to a retrognathic mandible (smaller, set back)
* Maxillary protrusion less common

*Do see with skeletal class 1
Can get inc OJ with class 1 skeletal. Incisors are proclined

Very rarely see with skeletal class 3, but possible
Class 3 incisors proclined in a way that gives them inc overjet *

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7
Q

OJ due to

3

A

skeletal pattern
tooth inclination
combination of both

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8
Q

if see clinically proclination UI, retroclination LI
think

A

lower lip trapped behind U= finger suck habit

develop an eye for what is causing incisor relationships

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9
Q

if see clinically proclination UI, retroclination LI
think

A

lower lip trapped behind U= finger suck habit

develop an eye for what is causing incisor relationships

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10
Q

vertical skeletal pattern for class II div 1

A

variety

low, high, ave - no rule
often slightly steep plane angle

any associated with inc OJ

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11
Q

transverse skeletal pattern for class II div 1

A

no particular association with transverse problems

slight narrow maxilla sometimes

any associated with inc OJ

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12
Q

SNA

A

sella to nasion
A depth of concavity of maxilla

rep maxilla to anterior cranial base

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13
Q

SNB

A

sella to nasion
B concavity of mandible

represent mandible to anteiror cranial base

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14
Q

ANB

A

difference between A and B, how much class I or II pt is

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15
Q

MxP/MnP

A

maxillary plane, Frankfurt plane
* orbitale to porion- should be parallel to floor

compared to mandibular plane

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16
Q

LAFH/TAFH

A

nasion to anterior nasal spine

anterior nasal spine to menton (base of mandibular symphsis)

should be 55%

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17
Q

soft tissues in class II div 1

A

Lips often incompetent due to prominence of incisors and/or underlying skeletal pattern

Lower lip trap can be aetiological factor in increased overjet
* Can cause proclination and inc OJ more
* But also side effect of proclination

If lips incompetent then special effort needed to achieve an anterior oral seal
* Mentalis muscle habitual inc to get lower lip in from UI to close with upper lip to achieve ant oral seal
* May posture forwards
* Can assess when in dental chair

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18
Q

achieving an anterior oral seal

3

A
  • Lip to lip seal by activity of circum-oral musculature
  • Mandible postured to allow lips to meet

or

  • Lower lip drawn up behind upper incisors
  • Tongue placed forwards between incisors to lower lip

or

Combination of these

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19
Q

dental factors in class II div 1

A

Increased overjet (incisors proclined or average?)

Overbite varies
* hand in hand with inc or reduced face height

Can see good alignment, crowding or spacing
* Crowding - upper lateral tucked behind Ucentrals, cont to OJ

Molar relationship
* Variable

Habitually parted lips may lead to drying of gingiva and exacerbation of any pre-existing gingivitis
* lead to hyperplastic gingivitis, exposure to air inc, OH poor inc

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20
Q

NNSH

A

non-nutritional sucking habit

thumb, fingers, blanket, lip, combination

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21
Q

NNSH effect

A

depends on duration and intensity

22
Q

occlusal features of NNSH

4

A

proclination of upper anteriors

retroclinatoin of lower anteriors

localised AOB or incomplete OB
* bilateral or unilateral

narrow upper arch (may see unilateral posterior crossbite)

23
Q

habit tx principles

3

A

Stop habit
* Reinforcement
* Removable appliance habit breaker
* Fixed appliance habit breaker

Allow spontaneous improvement

Treat residual malocclusion if required

child wants to stop makes easier

24
Q

when is it key for habit to be broken

A

Persisting beyond age of 9 more disruptive to occlusion, reduce chance of getting ideal occlusion with tx

OJ may improve - depends if lower lip a factor, if so unlikely
AOB spontaneous closure possible if habit stopped
Habit stopped before tx – as factor in relapse afert tx

25
Q

5 management options for class II div1

A

accept
attemt growth modification
simple tipping of teeth
camouflage
orthognathic surgery

26
Q

accepting class II div 1

when
warning

A

Mildly increased overjet

Significant overjet but not unhappy

treatment options be more difficult in the future
* correction when stopped growing more diff – e.g. teeth harder to move and no more growth

Advice re mouthguard

IOTN score low, aesthetic minimal
No great pt concerns

27
Q

2 modes of attempting growth modification in class II div1

A

headgear

functional appliance

28
Q

headgear

growth modification for class II div1

A

Try and restrain growth of maxilla horizontally and/or vertically

Not commonly used

Hard to know long term effect from evidence currently

Uses back of head as anchorage support, distalise upper molars can try and intrude upper molar

Reduced over bite and AOB

Hard to get 14+ hours wear – not going to wear out, need long time on to make effect

29
Q

functional appleance

growth modification for class II div1

A

“utilize, eliminate, or guide the forces of muscle function, tooth eruption and growth to correct a malocclusion”

Used mostly for class II division 1
* Can use for II div 2. Limited use for class III

Posture muscle forwards

Encourage mandibular condyles to grow as condyle extracted out of glenoid fossa

30
Q

types of functional appliance

A

removable (pt compliant dependent)
* tooth borne - twin block (most widely used globally)
* soft tissue borne - Frankel

fixed
* Herbst

31
Q

tooth borne fixed appliances

A

Twin block (most widely used globally)
* Clasps onto lower teeth
* Blocks hold mand forward in postured position
* Edge to edge more than class I
* Want good retraction to upper arch

Activator/bionator

32
Q

fixed appliance soft tissue borne

A

frankel (different types 1, 2, 3 and 4; use FRii for class ii)

soft tissue sulcus shield, aims to posture mandible and expansion of maxilla, effect alveolar growth – likely sim to other devices

33
Q

fixed functional appliances

A

herbst
most common fixed functional appliance
* Silver CoCr capping on teeth, connecting rod to hold mandible forward
* More likely to give efficient correction of occlusion
* Prone to break

34
Q

functional appliance aim

A

to produce restraint of maxillary growth and encourage mandibular growth

35
Q

functional appliance success depends on

A

favourable growth and enthusiastic pt

36
Q

therapeutic effect of functional appliances

A

Mostly dento-alveolar changes
* Distal movement upper dentition
* Mesial movement lower dentition
* Retroclination of upper incisors
* Proclination of lower incisors

Minor degree of skeletal changes
* RCT’s indicate that degree of maxillary restraint and mandibular growth is usually small (1-2mm)
* Significant variation in response

37
Q

dento-alveolar changes due to functional appliances

4

A
  • Distal movement upper dentition
  • Mesial movement lower dentition
  • Retroclination of upper incisors
  • Proclination of lower incisors
38
Q

when to use a functional?

A

Should be used during growth
If possible coincide with pubertal growth spurt but?

Options:
* Early use – about 10 years (2 phase tx)
* Later use – late mixed or early permanent dentition (1 phase tx)

39
Q

3 potential disadv of early functional appliance tx

A

Early skeletal effects from functional appliance or headgear therapy not maintained in long term

Overall treatment time increased, 2 phase treatment
* Early functional appliance plus retention - Can be hard to wear appliance after primary teeth exfoliate, but want to hold tx result until permanent dentition fully erupted
* Fixed appliances in early permanent dentition

Research shows little if any difference in results between those treated early and those who waited until permanent dentition

40
Q

3 potential adv of early functional appliance tx

A

Improve appearance earlier (teasing and potential psychological benefit)

Reduce risk of trauma

Often better compliance with appliance wear

41
Q

ideal candidate for functional appliance has

2

A

well aligned arches and complele or nearly permanent dentition

Inc OB – good, forward growth rotation of mandible, bodes well for func tx

42
Q

simple tipping of teeth for class II div 1

A

limited role in the contemporary treatment of increased overjets

unless
* V mild class II or class I
* Overjet due to proclined and space incisors
* Overbite favourable
* Only then after specialist assessment

e.g. occlusion not far from class I and only OJ needing correct

43
Q

risk of just simple tipping of teeth class II div 1 tx

2

A

iatrogenic class II div II created
* possible too class II first place
* no control on degree of OJ reduction

OB increased here
* Contemporary fixed appliances better tx option

44
Q

URA for simple tipping of upper incisors (OJ reduction)

A

Aim: please construct a URA to reduce OJ

Active: Roberts retractor 0.5mm HSSW, 0.5mm ID tubing
* Reduce OJ

Retention: Adam’s clasps on 6/6 0.7mm HSSW

Anchorage: good

Stops: mesial to 3/3 0.6mm flattened HSSW

Base plate: Flat anterior bite plane OJ+3mm
* Prop bite open, progressive trim to allow UI retraction

45
Q

camoflage for class II div1

A

older - stopped growing 15y+

fixed appliance correct incisor relationship (OJ) no attempt to fix jaw growth
* No growth mod happening, OJ reduced by tipping UI and LI
* Take out upper premolar to make space, retract canine and upper incisors to reduce OJ
* Lower incisors proclined

Not huge change in profile – dento alveolar tx only not skeletal

46
Q

possible camoflage tx options for class II div1

A

older pt, no longer growing

  • No growth mod happening, OJ reduced by tipping UI and LI
  • Take out upper premolar to make space, retract canine and upper incisors to reduce OJ
  • Lower incisors proclined

*Can see recession associated with LI, due to non growing limited alveolar bone to maintain coverage of root, causing recession - warn pt *

47
Q

when is growth complete in females

A

16-18y

48
Q

when is growth complete in males

A

18-20y

49
Q

orthognathic surgery for class II div 1

A

carried out when growth complete

severe A/P skeletal discrepancy and/or vertical discrepancy
* cannot correct occlusion with ortho alone

usually improve mandible surgically, sometimes maxilla too
* Surgical advance mandible Class II div I -* sometimes both need moved forward*
* Assess where discrep lies before, and pt concern (largely based)

fixed appliance is always required
at one or more of these times:
* before
* during
* after

50
Q

tx done here

A

Inc oJ fixed appliance to align arches

Shows too much upper gingival wants correct

Full unit class II occlusion And inc OJ
* Maxillary impaction – osteomy to reduce amount of show upper incisors and gingiva
* mandible advance to bring forward

After surgery more class I
* Elastics to hold in place

Now class I molar and incisor relationship
Lower face height reduced too as maxilla move up

BDS4 CDS Ortho (9 decks)

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