Class 2 Div 2

Question 1

What is the BSI definition of class 2 div2

Answer 1

The lower incisor occludes posterior to the cingulum plateau of the upper incisor
The upper incisors are retroclined
The OJ is reduced but can also be increased

Question 2

What are the 4 aetiological factors?

Answer 2

Skeletal
Soft tissue
Dental
Pathology

Question 3

What is the skeletal aetiology?

Answer 3

Usually associated with mild or moderate class 2
Typically reduced FMPA
Prominent chin (progenia)

Question 4

What pattern of mandibular growth is often associated with class2 div 2

Answer 4

Forward rotational pattern of growth

Question 5

What is the soft tissue aetiology of class 2 div 2?

Answer 5

High resting lower lip line (secondary to reduced LAFH and retroclined upper incisors)
Marked labio-mental fold
High masseteric forces can cause problems for ortho space closure

Upper 2s have shorter clinical crown, allowing them to escape the effect of the lower lip and trapping it

Question 6

What is the ‘strap effect’

Answer 6

Retroclined upper centrals as the laterals get stuck infront of the lower lip, pushing the centrals back
This also causes flare and rotation of laterals

Question 7

What are the dental features of class 2 div2

Answer 7

Retroclined upper centrals
Deep OB
OJ usually reduced
Class 2 bucal segments
Increased inter incisal angle
Upper laterals often crowded - mesial labially rotated (may be normal or proclined depending on position relative to lip line), with poorly developed cingulum
Reduced arch length (exacerbates crowding)

Question 8

What is an effect of an increased OB

Answer 8

Trauma to hard palate
Gingival stripping of attached labial mucosa of lower incisors

Question 9

What is the incidence of other dental anomalies in class 2 div 2 patients?

Answer 9

50% have a form of congenital dental anomaly (33% of which have impacted canines)

Question 10

What is the IOTN for a traumatic OB

Answer 10

4f

Question 11

What do the treatment options depend on?

Answer 11

Severity of malocclusion
Age and motivation of patient
Dental health
Patient concerns

Question 12

What are the 4 treatment options for class 2 div 2

Answer 12

Accept
Growth modification
Camouflage
Orthognathic treatment

Question 13

When is growth modification best carried out?

Answer 13

In growing patient
F- 12 +/- 2 yrs
M- 14 +/- 2 yrs

Question 14

Which severity of class 2 div 2 would growth modification be carried out and what would be the treatment aim?

Answer 14

In mild to moderate skeletal pattern 2

Convert class 2 div 2 to class 2 div 1, and detail occlusion with fixed ortho

Question 15

What is the aim of the functional appliance and give an example of one which is used?

Answer 15

Aim is to procline the upper incisors

Modified twin block with springs/ sectional fixed appliance

Question 16

What is camouflage?

Answer 16

Accepting the patients underlying skeletal base relationship and aiming to treat to class 1 incisor relationship

Can be used in mild to moderate class 2 skeletal patterns

Question 17

How is camouflage achieved?

Answer 17

With fixed appliances
Inter incisal angle is corrected by a combination of palatal root torque of upper incisors and proclination of lower incisors.

Question 18

What is required for stable correction of class 2 div 2

Answer 18

Overbite reduction
Correction of inter incisal angle (reduction) -otherwise OB will relapse

Question 19

When is a functional appliance considered

Answer 19

When there is an AP discrepancy

Question 20

How is OB corrected

Answer 20

URA with FABP (OJ + 3mm)

Question 21

When is orthognathic surgery considered?
And outline this treatment

Answer 21

When the malocclusion is severe

Pre surgery fixed appliances (decompensate) to achieve class 1 incisor relationship
Surgery
Post surgery fixed appliances to correct posterior open bite

Question 22

What is the inter incisal angle (and what is it for class 2 div 1 and class 2 div 2)

Answer 22

Inter incisal angle is the external angle created by the long axis of the upper and lower incisors
Average is 130 degrees

Reduced in class 2 div1
Increased in class 2 div2