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Ortho > Class II div I > Flashcards

Class II div I Flashcards

1
Q

What is the AP skeletal relationship in class 2 div 1 malocclusions

A
  • Usually class 2 with mandibular retrognathia

- May have class 1 or 3 with dentoalveolar compensation due to other factors

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2
Q

What is the vertical skeletal relationship in class 2 div 1

A

Variable

Normal, increased or decreased

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3
Q

What is the skeletal transverse relationship in class 2 div 1?

A
  • Normal
  • Crossbite secondary to a digit sucking habit
  • Lingual cross bite if the mandible is very small
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4
Q

Signs of habit as the aetiological factor for class 2 div 1

A
  • Increased OB and OJ
  • Proclined upper incisors (Inc OJ) +/- spacing
  • Retroclined lower incisors +/- crowding
  • Asymmetrical AOB
  • Unilateral posterior crossbite
  • Mandibular displacement
  • Non coincident dental centre line
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5
Q

Is the soft tissue environment in class 2 div 1 favourable or unfavourable?

A

Usually unfavourable due to the proclined upper incisors

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6
Q

List the examples of soft tissue etiological factors in class 2 div 1 malocclusions

A
  • Lower lip trap
  • Strap lip
  • Incompetent lips +/- adaptive oral seal
  • Endogenous tongue thrust
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7
Q

Why may cause incompetent lips in class 2 div 1

A
  • Prominent proclined upper incisors
  • Increased vertical dimensions
  • AOB secondary to habit
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8
Q

List the ways an oral seal can be achieved with incompetent lips

A
  • Circumoral muscular activity to achieve lip to lip seal
  • Mandible postured forward to achieve lip to lip seal
  • Lip to palate (lip trap)
  • Tongue to lower lip
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9
Q

How does a lip trap (lower lip to palate) result in class 2 div 1

A

Proclination of the upper incisors

+/- retroclination of the lower incisors

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10
Q

List the dental features seen in class 2 div 1 patients

A
  • Class II div 1 incisor
  • Class II molar
  • Increased overjet
  • Variable openbite
  • Crowding of LLS
  • Spacing of ULS
  • Crossbite secondary to habit
  • ULS gingivitis secondary to lip incompetence
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11
Q

What do you assess during clinical assessment of mandibular position?

A

Assess for any posturing or displacement

Make sure you are assessing facial profile at rest

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12
Q

What is the most favourable growth in class 2 div 1

A

Downwards and forwards

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13
Q

When to refer class 2 div 1

A
  • Unfavourable facial growth
  • Grossly incompetent lips
  • Severe skeletal discrepancy
  • Molars more than full unit class 2
  • Severe crowing (>1 unit)
  • Severe dentoalveolar compensation
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14
Q

Treatment considerations for class 2 div 1

A
  • Patient attitude
  • Age
  • Direction of growth (favourable or not)
  • Aetiology
  • Degree of skeletal discrepancy
  • Stability of overjet post op
  • Degree of dentoalveolar compensation
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15
Q

What are the main treatment options for class 2 div 1

A
  • Accept
  • Habit cessation
  • Growth modification (functionals)
  • Orthodontic camouflage (URA or FA)
  • Surgery
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16
Q

Tx options for increased OJ with class I or mild class II skeletal pattern

A

1) URA to tilt upper incisors into class I - may follow with fixed appliance if theres crowding
2) Fixed appliance +/- extractions if theres crowding

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17
Q

What will determine the treatment to reduce an increased overjet with class I or mild class II

A
  • The degree of crowding

- The movement required to reduce overjet (URA if only tilting but fixed required for bodily movement)

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18
Q

List the extraction patterns in class 2 div 1 and explain the indications and reasoning

A 
44/44 if space requirement is large 
44/55 if space requirement is moderate and molar relationship is class 2 as it corrects molar and aids OJ reduction
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19
Q

What underlying skeletal pattern for class 2 div 1 is growth modification indicated

A

Mild-moderate class II skeletal patterns

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20
Q

List the aims of the functional appliance phase in growth modification (class 2 div 1)

A
  • Correct the skeletal pattern
  • Reduce OJ and OB
  • Correct any transverse issue
  • Reduce anchorage demand for fixed appliance stage
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21
Q

How can functional appliances correct skeletal pattern (in class 2 div 1)?

A
  • Retrognathic mandible - enhancing mandibular growth

- Prognathic maxilla - slight maxillary restraint +/- use of EOT

22
Q

When can growth modification be carried out

A

During pubertal growth spurt - age 11-14

23
Q

Describe the phases of treatment in growth modification

A

Functional appliance or EOT as first phase

Fixed appliance +/- extractions as second phase

24
Q

Aims of the fixed appliance phase in growth modification

A

Align teeth, correct torque/tip of teeth, correct rotations

25
Q

Aims of ortho camouflage in class 2 div 1

A
  • Accept and disguise skeletal problem by levelling arches
  • Produce normal OJ and OB
  • Relieve crowding
  • Correct buccal segment relationship
26
Q

What are the favourable skeletal factors for camouflage in class 2 div 1

A
  • Mild-moderate class II (or class I)
  • Small ANB
  • Absence of crossbite (no transverse issues)
  • Vertical facial proportions are acceptable
  • Growing patient with favourable growth pattern
27
Q

What are the favourable dental factors for camouflage in class 2 div 1

A
  • OJ <9mm
  • Average or slightly increased OB
  • Mild-moderate crowding
  • No dental compensation
  • Molar relationship less than half unit class II
28
Q

Other favourable features for ortho camouflage in class 2 div 1

A

Absence of habit
No mandibular displacement
Tx carried out in the permanent dentition

29
Q

What options can be used for ortho camouflage for the treatment of class 2 div 1

A
  • URA

- Fixed appliance +/- extractions

30
Q

When would you use removable appliances over fixed in the tx of class 2 div 1 (ortho camouflage)

A

Removable indicated in a growing pt with average FMPA and no adverse soft tissue factors.
Tx can be achieved by simple movement (tipping)

31
Q

When would you use fixed appliances over removable in the tx of class 2 div 1 (ortho camouflage)

A

Fixed if more complex movement required e.g. rotations present or intrusion required for OB reduction.

32
Q

Benefits of extractions in the upper and lower arch for tx of class 2 div 1

A
  • Relieve crowding
  • Correction of LLS and ULS inclination
  • Improve OB
  • Corrects molar relationship
33
Q

What are the indications for surgery of class 2 div 1 patients?

A
  • ANB >8
  • OJ >10 mm
  • Severe vertical or transverse discrepancies
  • Non-growing patient
34
Q

Aims of surgical correction of class 2 div 1

A
  • Correct skeletal pattern
35
Q

Stability of class 2 div 1 post op depends on:

A
  • Favourable soft tissue environment - lower lip control (ideally should cover lower 1/3rd of upper incisors)
  • Favourable mandibular growth
36
Q

What are the etiological dental factors in class 2 div 1?

A
  • ULS exacerbating OJ by labially excluding central incisors out of the arch
  • Periodontal disease and drifting of teeth causing proclination of ULS
37
Q

How does a habit play an aetiological role in class 2 div 1 malocclusions?

A 
Incr OJ and retroclination of LLS occurs due to habits 
Thus exacerbate class II pattern or lead to class II div 1 on a class I or III skeletal base
38
Q

How does age affect the treatment options for class 2 div 1?

A

In an adult patient, the options are limited to fixed appliances and surgery.

39
Q

Why is backward growth of the mandible unfavourable in class 2 div 1 malocclusions?

A
  • Worsens AP discrepancy

- Reduces the likelihood of lip competence post op

40
Q

What is the common extraction pattern for moderate crowding in class 2 div 1 with mild skeletal class 2 base?

A

44/55
Favours forward movement of the lower molar to correct molar relationship
Aids retraction of the ULS

41
Q

Why are extractions needed for overbite reduction

A

OB reduction requires space therefore extractions required if space cannot be made elsewherE

42
Q

Tx options for moderate-severe skeletal class 2 patterns in tx of class 2/1

A
  • Growth modification
  • Orthodontic camouflage
  • Surgery
43
Q

Describe how orthodontic camouflage is achieved for tx option of class 2/1

A

Retraction of upper incisors using fixed appliance or URA

44
Q

Radiographic assessment of class 2 div 1 patients indicating-

1) class 2 skeletal pattern
2) retrognathic mandible
3) prognathic maxilla

A

1) ANB >4
2) SNB reduced or obtuse cranial base angle
3) SNA increased or increased cranial base length

45
Q

What does evidence suggest about early interceptive treatment (growth mod?)

A

Early two stage treatment does not have any significant benefits over conventional treatment, apart from self-esteem

46
Q

What causes strap like lips?

A

Hyperactive musculature (mentalis)

47
Q

What occurs with mandibular posture to achieve anterior oral seal?

A

Soft tissues promote DAC to reduce the severity of the underlying skeletal pattern

48
Q

What occlusal features result in a lower lip trap

A

Increased or incomplete OB

49
Q

What occurs with a tongue to lower lip adaptive seal?

A

Prcolination of the ULS

50
Q

What occlusal features is a tongue to lower lip adaptive seal associated with?

A

Incomplete overbite, increased vertical dimensions, grossly incompetent lips

51
Q

What is a primary endogenous tongue thrust?

A

Rare neuromuscular defect causing the tongue to push forward on swallowing

52
Q

What is the main concern with class 2 div 1 patients?

A

Risk of trauma to the ULS

Ortho (20 decks)

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