Class II Division 1

Question 1

What is the BSI definition of Class II Division 1 Malocclusion?

Answer 1

The lower incisor edges lie posterior to the cingulum plateau of the upper incisors
There is an increased overjet
The upper central incisors are proclined or of average inclination

Question 2

Why do you treat Class II div 1 malocclusions?

Answer 2

Aesthetic concerns
Dental health concerns (risk of trauma especially with incompetent lips)

Question 3

What skeletal pattern (A/P) is typical of a Class II div 1 malocclusion?

Answer 3

Class II skeletal pattern
Commonly due to a retrognathic mandible (rather than a maxillary prognathism)

Question 4

What is the FMPA typically for this malocclusion?

Answer 4

A reduced FMPA

Question 5

What habit can be associated with this malocclusion?

Answer 5

A sucking habit of things such as a thumb, fingers, a blanket, a lip or a combination of things.
Effect depends on duration and intensity

Question 6

What are the occlusal features of a sucking habit?

Answer 6

Proclination of upper anteriors
Retroclination of lower anteriors
Localised AOB or incomplete OB (to have a skeletal effect, needs to be a bad habit)
A narrow upper arch

Question 7

What are the habit treatment principles?

Answer 7

Stop the habit
Allow spontaneous improvement of malocclusion
Treat residual malocclusion if required

Question 8

How can you stop a habit of sucking?

Answer 8

Reinforcement- requires patient co-operation
Removable appliance habit breaker - requires patient co-operation
Fixed appliance habit breaker- last resort

Question 9

What are the management options for a Class II div 1 malocclusion?

Answer 9

Accept- aware of risk of trauma
Attempt growth modification- has to be at the right age
Simple tipping of the teeth (URA)
Camouflage
Orthognathic surgery

Question 10

What are functional appliances used for?

Answer 10

Functional appliances utilise, eliminate, or guide the forces of muscle function, tooth eruption and growth to correct a malocclusion
Used mostly for Class II div 1

Question 11

What are the different types of functional appliance?

Answer 11

Removable
Fixed

Question 12

What are the removable types of functional appliance?

Answer 12

Tooth borne - twin-block, activator
Soft tissue borne- Frankel (FR II)

Question 13

How are functional appliances used in growth modification?

Answer 13

They aim to produce restraint of maxillary growth & encourage mandibular growth
Success depends on favourable growth & an enthusiastic patient

Question 14

What are the therapeutic effects of functional appliances?

Answer 14

Mostly dento-alveolar changes
—Distal movement upper dentition
—Mesial movement lower dentition
—Retroclination of upper incisors
—Proclination of lower incisors
Minor degree of skeletal changes

Question 15

When should you use a functional appliance?

Answer 15

It should be used during growth
If possible it should coincide with pubertal growth spurt
Early use- about 10 years old (2 phase treatment)
Later use- late mixed or early permanent dentition (1 phase treatment)
—ideally during period of maximal growth
—Females 11-13
—Males 13-15

Question 16

What can early use of twin block create?

Answer 16

Early use can create gaps

Question 17

What are the potential disadvantages of early treatment?

Answer 17

Early skeletal effects from functional appliance or headgear therapy not maintained in long term
Overall treatment time is increased, 2 phase treatment
–early functional appliance plus retention
–fixed appliances in early permanent dentition

Question 18

What are the potential benefits of early treatment?

Answer 18

Improve appearance earlier (teasing and potential psychological benefit)
Reduces the risk of trauma
Often better compliance with appliance wear

Question 19

When are URA’s appropriate for treatment?

Answer 19

Very mild Class II
There is an overjet due to proclined and spaced incisors
Overbite favourable

Question 20

What URA can you design to retrocline the anterior teeth? (reduce the overjet)

Answer 20

Active: Roberts retractor 0.5mm in ID tubing
Retention: Adams clasps 16,26 0.7mm HSSW
Anchorage: mesial stops 13,23
Baseplate: flat anterior bite plane

Question 21

What does camouflage treatment involve?

Answer 21

Fixed appliances
—If the goal is to reduce the overjet may need upper arch extractions to give space (for distal movement)

Question 22

When is orthognathic surgery carried out?

Answer 22

Carried out when growth is complete
Skeletal discrepancy is severe in A/P & or vertical direction
Usually involves mandibular surgery, but may also involve maxillary surgery
Fixed appliances required
–Before surgery
–During surgery
–After surgery