Class II div I Flashcards
What is the BSI incisor definition of a class II div I malocclusion?
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
What is the incidence of a class II div I relationship?
15-20%
Why treat a class II div I malocclusion?
Aesthetic concerns
trauma risk
What is the SNA angle of a Class II relationship?
Increased
What is the ANB angle of a class II relationship?
Increased
What is the aetiology of a class II div 1 relationship?
Skeletal base - commonly retrognathic mandible
Dental factors - tooth inclination
Soft tissues e.g. lip trap
Habits - digit sucking
What is the treatment for breaking a digit sucking habit?
To STOP habit
- Re-enforcement
- Removable appliance habit breaker
- Fixed appliance habit breaker
Allow spontaneous improvement
What are some management options of class II div I?
Accept - explain trauma risk
Growth modification - if right age group
Simple tipping of teeth
Camouflage
Orthognathic surgery
Generally, how do functional appliances work?
Utilises, eliminates or guides the forces of muscle function, tooth eruption & growth to correct a malocclusion
How do twin blocks work?
Aim to produce restraint of maxillary growth & encourage mandibular growth by posturing the mandible forwards.
When should a functional appliance ideally be used?
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.
What are the disadvantages of early treatment of a class II div I malocclusion?
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
What are benefits of early treatment of Class II div I malocclusion?
Improve appearance earlier
Reduce trauma risk
Often better compliance with appliance wear when younger
Why is tipping of teeth not that useful for class II div I?
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
What active component would you use in a URA to retrocline anterior teeth?
Roberts retractor
Why is fixed ortho better than URA for Class II div I?
Moving teeth in a more controlled way than URA - root position more controlled
Why would orthognathic surgery be carried out for a patient with class II div I?
If malocclusion very severe - sk discrepancy severe in AP and/ or vertical direction
If patient unlikely to be compliant with functional appliances
When is orthognathic surgery carried out and what else is required before?
Carried out when growth is complete
Fixed appliances required - before, during and after surgery.
What are the iotn dhc scores for class II div I malocclusions?
3a - 3.5mm - 6mm - incompetent lips
4a - 6-9mm
5a - >9mm
In what situations would you accept a class II div I malocclusion?
If the overjet is only mildly increased
If patient is currently happy with bite, or does not want ortho treatment.
Advise about trauma.
