Class II Division 2 Malocclusion

Question 1

What skeletal pattern is commonly seen in Class II div 2 cases?

Answer 1

• Commonly mild skeletal II but may be moderate or severe
• Vertical dimension usually reduced with reduced lower face height leading to increased overbite (associated with up and forward growth rotation of mandible which further increases the overbite)

Question 2

How do soft tissues cause Class II div 2?

Answer 2

• Influence of soft tissues usually mediated by skeletal pattern
• If lower face height reduced lower lip line higher than normal causing retroclination (in some cases the lateral incisors escape from the action of the lip meaning they are of average inclination or proclined)
• Class II div 2 also can be caused by bimaxillary retroclination under soft tissue influence

Question 3

How does class II div 2 affect dental factors

Answer 3

• Lack of space for upper lateral incisors which are usually rotated mesiobuccally
• Lower incisors crowded due to retroclination
• Retroclination of upper incisors leads to an increased inter-incisal angle
• Lack of occlusal stop for lower incisors cause increased overbite or traumatic overbite

Question 4

What is the management of Class II div 2?

Answer 4

• Only accept where the problem is mild, the incisors occlude with tooth tissue and no other occlusal anomalies such as crowding
• Usually need to correct incisor relationship but keeping it stable is difficult. Correct overbite and interincisal angle to 135 (requires torque) to create occlusal stop using fixed
• If lower arch crowded and xla required, try prevent lingual movement of lower incisors during space closure and xla further posteriorly

Question 5

How can you reduce OB and correct incisor relationship?

Answer 5

1. Intrusion of the incisors: difficult, use fixed
2. Following OB reduction - correct interincisal angle by root torque to create occlusal stop and prevent relapse of OB
   - Mild cases: treat by non extraction and fixed
   - Crowding in lower arch xla 5s but used fixed to stop lower labial segment moving lingually (if premolars xla in lower arch then xla in upper arch usually 4s)
   - If lower arch non-extraction, upper arch can be treated by distalising buccal segments (if less than half unit class II) or xla of upper premolars

Question 6

Are functional appliances used in Class II div 2 cases?

Answer 6

Not commonly as not usually severe class II

Question 7

How can surgery be used to treat Class II div 2 cases?

Answer 7

• Done in pts with severe skeletal class II
• Stable correction may not be possible
• Phases of pre-surgical fixed appliances needed to align teeth
• Sagittal split forward