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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
Aims of ortho camouflage in class 2 div 1
- Accept and disguise skeletal problem by levelling arches - Produce normal OJ and OB - Relieve crowding - Correct buccal segment relationship
26
What are the favourable skeletal factors for camouflage in class 2 div 1
- 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
What are the favourable dental factors for camouflage in class 2 div 1
- OJ <9mm - Average or slightly increased OB - Mild-moderate crowding - No dental compensation - Molar relationship less than half unit class II
28
Other favourable features for ortho camouflage in class 2 div 1
Absence of habit No mandibular displacement Tx carried out in the permanent dentition
29
What options can be used for ortho camouflage for the treatment of class 2 div 1
- URA | - Fixed appliance +/- extractions
30
When would you use removable appliances over fixed in the tx of class 2 div 1 (ortho camouflage)
Removable indicated in a growing pt with average FMPA and no adverse soft tissue factors. Tx can be achieved by simple movement (tipping)
31
When would you use fixed appliances over removable in the tx of class 2 div 1 (ortho camouflage)
Fixed if more complex movement required e.g. rotations present or intrusion required for OB reduction.
32
Benefits of extractions in the upper and lower arch for tx of class 2 div 1
- Relieve crowding - Correction of LLS and ULS inclination - Improve OB - Corrects molar relationship
33
What are the indications for surgery of class 2 div 1 patients?
- ANB >8 - OJ >10 mm - Severe vertical or transverse discrepancies - Non-growing patient
34
Aims of surgical correction of class 2 div 1
- Correct skeletal pattern
35
Stability of class 2 div 1 post op depends on:
- Favourable soft tissue environment - lower lip control (ideally should cover lower 1/3rd of upper incisors) - Favourable mandibular growth
36
What are the etiological dental factors in class 2 div 1?
- ULS exacerbating OJ by labially excluding central incisors out of the arch - Periodontal disease and drifting of teeth causing proclination of ULS
37
How does a habit play an aetiological role in class 2 div 1 malocclusions?
``` 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
How does age affect the treatment options for class 2 div 1?
In an adult patient, the options are limited to fixed appliances and surgery.
39
Why is backward growth of the mandible unfavourable in class 2 div 1 malocclusions?
- Worsens AP discrepancy | - Reduces the likelihood of lip competence post op
40
What is the common extraction pattern for moderate crowding in class 2 div 1 with mild skeletal class 2 base?
44/55 Favours forward movement of the lower molar to correct molar relationship Aids retraction of the ULS
41
Why are extractions needed for overbite reduction
OB reduction requires space therefore extractions required if space cannot be made elsewherE
42
Tx options for moderate-severe skeletal class 2 patterns in tx of class 2/1
- Growth modification - Orthodontic camouflage - Surgery
43
Describe how orthodontic camouflage is achieved for tx option of class 2/1
Retraction of upper incisors using fixed appliance or URA
44
Radiographic assessment of class 2 div 1 patients indicating- 1) class 2 skeletal pattern 2) retrognathic mandible 3) prognathic maxilla
1) ANB >4 2) SNB reduced or obtuse cranial base angle 3) SNA increased or increased cranial base length
45
What does evidence suggest about early interceptive treatment (growth mod?)
Early two stage treatment does not have any significant benefits over conventional treatment, apart from self-esteem
46
What causes strap like lips?
Hyperactive musculature (mentalis)
47
What occurs with mandibular posture to achieve anterior oral seal?
Soft tissues promote DAC to reduce the severity of the underlying skeletal pattern
48
What occlusal features result in a lower lip trap
Increased or incomplete OB
49
What occurs with a tongue to lower lip adaptive seal?
Prcolination of the ULS
50
What occlusal features is a tongue to lower lip adaptive seal associated with?
Incomplete overbite, increased vertical dimensions, grossly incompetent lips
51
What is a primary endogenous tongue thrust?
Rare neuromuscular defect causing the tongue to push forward on swallowing
52
What is the main concern with class 2 div 1 patients?
Risk of trauma to the ULS

Ortho (20 decks)

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