Class II div I

Question 1

What is the BSI incisor definition of a class II div I malocclusion?

Answer 1

The lower incisor edges lie posterior to the cingulum plateau of the upper incisors
Upper central incisors are proclined or average inclincation
Overjet is increased

Question 2

What is the incidence of a class II div I relationship?

Answer 2

15-20%

Question 3

Why treat a class II div I malocclusion?

Answer 3

Aesthetic concerns
trauma risk

Question 4

What is the SNA angle of a Class II relationship?

Answer 4

Increased

Question 5

What is the ANB angle of a class II relationship?

Answer 5

Increased

Question 6

What is the aetiology of a class II div 1 relationship?

Answer 6

Skeletal base - commonly retrognathic mandible
Dental factors - tooth inclination
Soft tissues e.g. lip trap
Habits - digit sucking

Question 7

What is the treatment for breaking a digit sucking habit?

Answer 7

To STOP habit
- Re-enforcement
- Removable appliance habit breaker
- Fixed appliance habit breaker

Allow spontaneous improvement

Question 8

What are some management options of class II div I?

Answer 8

Accept - explain trauma risk
Growth modification - if right age group
Simple tipping of teeth
Camouflage
Orthognathic surgery

Question 9

Generally, how do functional appliances work?

Answer 9

Utilises, eliminates or guides the forces of muscle function, tooth eruption & growth to correct a malocclusion

Question 10

How do twin blocks work?

Answer 10

Aim to produce restraint of maxillary growth & encourage mandibular growth by posturing the mandible forwards.

Question 11

When should a functional appliance ideally be used?

Answer 11

During the pubertal growth spurt
Girls - 9-14
Boys - 10-15

Early use - 10 years old - 2 phase tx.
Late use - late mixed or early permanent dentition - 1 phase tx.

Question 12

What are the disadvantages of early treatment of a class II div I malocclusion?

Answer 12

Early skeletal effects from functional appliance not maintained long-term
Overall tx. time increased - 2 phase treatment
Research shows little difference in results between early treatment and those who waited until permanent dentition

Question 13

What are benefits of early treatment of Class II div I malocclusion?

Answer 13

Improve appearance earlier
Reduce trauma risk
Often better compliance with appliance wear when younger

Question 14

Why is tipping of teeth not that useful for class II div I?

Answer 14

Only works for VERY MILD class II div I - if large OJ and you tip teeth you are just making into another malocclusion - class II div II

Question 15

What active component would you use in a URA to retrocline anterior teeth?

Answer 15

Roberts retractor

Question 16

Why is fixed ortho better than URA for Class II div I?

Answer 16

Moving teeth in a more controlled way than URA - root position more controlled

Question 17

Why would orthognathic surgery be carried out for a patient with class II div I?

Answer 17

If malocclusion very severe - sk discrepancy severe in AP and/ or vertical direction
If patient unlikely to be compliant with functional appliances

Question 18

When is orthognathic surgery carried out and what else is required before?

Answer 18

Carried out when growth is complete
Fixed appliances required - before, during and after surgery.

Question 19

What are the iotn dhc scores for class II div I malocclusions?

Answer 19

3a - 3.5mm - 6mm - incompetent lips
4a - 6-9mm
5a - >9mm

Question 20

In what situations would you accept a class II div I malocclusion?

Answer 20

If the overjet is only mildly increased
If patient is currently happy with bite, or does not want ortho treatment.

Advise about trauma.