Malocclusion Class 2 Div 2

Question 1

Class 2 div 2

Answer 1

-The lower incisor edge lie posterior to the cimgulum plateau of upper central incisors

• Upper central incisors are Retroclined.
  Indices - 10-18%

Question 2

Feature of class 2 div 2
Skeletal.

Answer 2

• Saggital - often mild skeletal 2 can be SK1 or SK 3.
• Vertical- Reduced LAFH ( lower anterior face height) and MMA ( maxi mandibular enhancement)
• Transverse - Maxillary base broad relative to mandible.
• Chin - well developed
• Angle - well developed
• Profile- usually pleasing
• High cranial base angle - mandibular retrognathia
• Longer cranial base - prognathic max
• low face height
• low MMP angle

Question 3

Feature of class 2 div 2
Facial growth

Answer 3

• Often favourable but variable.
• Anterior growth rotation

Question 4

Feature of Class 2 div 2
Soft tissues

Answer 4

• high resting lower lip line ( due to low lower face height)
• typically strap like lower lip
• Marked labio-mental fold.
• high Masseteric muscle forces.
• high lower lip covers 1/1 but not always 2/2 because of height and position of lateral incisors.

Question 5

Feature of class 2 div 2
Dental

Answer 5

• upper incisors extruded
• 1/1 Retolroclined upper central incisors
• lower incisors Retroclined or Bimaxillary retroclination
• OB deep
• OJ. Average / slight increased/ usually decrease
• Buccal segment - Class 2 tendency. Can also be Class 1 or 3 scissor bite 4/4.

Question 6

Treatment options

Answer 6

• Accept
  1- orthodontic tx : URA with anterior bite plane and upper and lower fixed appliances

2- Functional appliance - convert to a Class 2/1 incisor relationship first then fixed appliances.

3- orthognathic approach - orthodontic decompensation and orthognathic surgery

Question 7

Favourable feature

Answer 7

-small ANB difference : mild SK discrepancy
- growing pt

Question 8

Upper removable appliance

Answer 8

• Active- anterior bite plane ( OJ+2mm)
• Retention - Adams crib (premolar and molars)
• Anchorage - palatal coverage
• Baseplate - palatal coverage

May be used in conjunction with HG (EOT) to aid correction of buccal segments.

Question 9

Treatment of Class 2 div 2
Overbite reduction

Answer 9

• easier in growing child
• requires change in lower incisor edge upper incisor root centroid relationship
• For stable overbite reduction change the interiincisal angle (lower edge to upper root centroid reln).

Question 10

Orthodontic Correction
Minimal space requirement

Answer 10

Anchorage loss is a consideration as upper incisors align to average inclination.

Question 11

Orthodontic correction
Crowded cases

Answer 11

• Create space with upper arch premolar Xta.
• Headgear +/- URA (Nudger appliance - its use to achieve distal movement of teeth) may be required to create additional space or to reinforce anchorage.
• Followed by upper and lower fixed appliances

To achieve :
- level and align teeth
- reduce overbite
- correct the interincisal angle
- create class 1 incisor relationship

Question 12

Severely crowded class 2 div 2 tx ?

Answer 12

• Xtn premolars
• URA and headgear fitted
• followed by upper and lower Fixed appliances and cont. headgear support at night.

Question 13

Skeletal discrepancy the which tx?

Answer 13

• Other cases for stable overbite reduction change the interincisal angle ( lower incisal edge to upper root centroid)

But This case by proclining the upper incisors and then bringing the lower arch forwards using a functional appliance or surgery.

Question 14

Functional appliance / skeletal discrepancy

Answer 14

Phase 1- Convert the class 2/2 into class 2/1 incisor relationship and treat with functional appliance.

Phase 2- After functional phase, fixed appliances to fully align teeth , +/- extractions or headgear.