Class II Division 2 Malocclusion

Question 1

What is the BSI definition of a class II div 2 malocclusion

Answer 1

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

Question 2

What is the incidence of class II div 2 incisor relationship?

Answer 2

5-18%

Question 3

Describe the antero-posterior skeletal aetiology of class II div 2 malocclusion

Answer 3

• usually associated with mild/moderate class II skeletal base
  
  • can also be class I or class III

Question 4

Describe the vertical skeletal aetiology of class II div 2 malocclusion

Answer 4

• typically reduced
  
  • reduced FMPA
• often associated with forward rotational growth of the mandible
  
  • prominent chin
    
    • progenia

Question 5

Describe the soft tissue aetiology of class II div 2 malocclusion

Answer 5

• high resting lower lip line
  
  • across upper incisors
  • results in retroclined upper incisors
• reduced lower face height
  
  • causes marked labio-mental fold
• high masseteric forces
  
  • orthodontic space closure problems
• lip trap
  
  • upper laterals have shorter crowns
  • escape the effect of lower lip forces
  • lip trapped behind upper laterals

Question 6

Describe the dental aetiology of class II div 2 malocclusion

Answer 6

• retroclined upper incisors
• retroclined lower incisors
  
  • strap like activity from lower lip
• lateral incisors rotated and flared
  
  • mesio-labial rotation
  • may be prolined or average
• class II canine and buccal segment
• arch length reduced
  
  • exacerbates crowding
  • especially in upper 2 region
• poor cingulum on lateral incisors
  
  • undeveloped
  • lack of cingulum rest
  • reduced interdigitated stop
  • difficult to correct overbite
• deep, potentially traumatic overbite
  
  • complete or incomplete
  • trauma to palate from lower incisors
  • gingival stripping by upper incisors
    
    • attached gingiva removed
• overjet usually reduced

Question 7

Is inter-incisal angulation increased or decreased in class 2 div II malocclusion?

Answer 7

increased

Question 8

Why might a class II div 2 malocclusion be treated?

Answer 8

• aesthetic concerns
• dental health concerns
  • traumatic overbite
    
    • IOTN 4f

Question 9

What do the treatment options for a class II div 2 malocclusion depend on?

Answer 9

• severity of malocclusion
• age and motivation of patient
• dental health
• patient concerns

Question 10

What are the treatment options for a class II div 2 malocclusion?

Answer 10

• accept
• growth modification
• camouflage
• orthognathic surgery

Question 11

When can a class II div 2 malocclusion be accepted?

Answer 11

• acceptable aesthetics
• patient not concerned or suitable
• overbite not a significant problem

Question 12

How can growth modification be used to treat a class II div 2 malocclusion?

Answer 12

• growing patients
  
  • adolescent growth spurt
    
    • male - 13-15
    • female 11-13
• suitable for mild to moderate skeletal class II
• convert class II div 2 into class II div 1
  
  • detail occlusion with fixed appliances
• proclination of upper incisors
  
  • modified twin block
  • springs or screw
  • upper sectional fixed appliance

Question 13

What are the components of a modified twin block and how must it be worn?

Answer 13

• upper twin block
  
  • ELSA spring
    
    • prolines labial segment
  • midline screw
    
    • transverse adjustment
• to be worn 22 hours a day
  
  • 6-9 months full time wear
  • 3 months part time wear
  • followed by fixed appliance

Question 14

How can camouflage be used to treat a class II div 2 malocclusion?

Answer 14

• accept underlying skeletal base and aim to treat to class I incisor relationship
• suitable for mild/moderate class II skeletal
• careful extraction decision
  
  • space closure difficult in low angle cases
    
    • high masseteric forces
• fixed appliances
  
  • overbite reduction
  • reduction of interincidal angle

Question 15

How can inter-incisal angel be corrected in a class II div 2 malocclusion?

Answer 15

• fixed appliance
  
  • palatal root torque for upper incisors
  • proclination of lower incisors
• upper incisor torquing
  
  • needs adequate cancellous bone
    
    • palatal to upper incisors
  • risk of root resorption
    
    • high forces

Question 16

When might orthognathic surgery be required to treat a class II div 2 malocclusion?

Answer 16

• too severe a malocclusion for orthodontics
  
  • A-P
  • vertical
• non-growing patients
  
  • 18 years and older
• profile concerns

Question 17

How is orthognathic surgery used to treat a class II div 2 malocclusion?

Answer 17

• pre surgical
  
  • fixed appliance to decompensate

Question 18

Describe the stability of a corrected class II div 2 malocclusion and what retention is required

Answer 18

• future facial growth can affect stability
  
  • difficult to treat
• long term bonded retention
  
  • rotated laterals
  • deep overbite

Question 19

When should a class II div 2 malocclusion be referred?

Answer 19

• early referral
  
  • deep overbite best corrected during growth
    
    • growth modification if AP discrepancy
    • functional appliance
• consider other dental anomalies