class II div 1

Question 1

What is the BSI definition of Class II div 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

What are the prevalence rates for different types of malocclusion (incisor relationship)?

Answer 2

Class I - 67-72%
Class II div 1 - 15-20%
Class II div 2 - 10%
Class III - 3%

Question 3

Why is it important to treat a class II div 1 malocclusion?

Answer 3

Aesthetic concerns
Risk of trauma to prominent incisors (especially if incompetent lips)
Increased likelihood of trauma if overjet >9mm

Question 4

What is the normal SNA value?

Answer 4

81º +/-3

Question 5

What is the normal SNB value?

Answer 5

78º +/-3

Question 6

What is the normal ANB value?

Answer 6

3º +/-2

Question 7

What is the normal FMPA?

Answer 7

27º +/-4

Question 8

What is the normal UI/MxP value?

Answer 8

109º +/-6

Question 9

What is the average LI/MnP value?

Answer 9

93º +/-6

Question 10

What is the average LAFH/TAFH?

Answer 10

55%

Question 11

Describe the soft tissue characteristics often seen in class II div 1 malocclusions

Answer 11

Incompetent lips due to prominent incisors or underlying skeletal pattern
Achieving an oral seal may require lip to lip seal or lower lip drawn up behind incisors with tongue placed forwards between incisors to lower lip

Question 12

What are some dental factors associated with class II div 1 malocclusion?

Answer 12

Increased overjet
Variable overbite
Varying alignment (crowding or spacing)
Potential exacerbation of gingivitis due to habitually parted lips

Question 13

Describe the occlusal features of sucking habits in class II div 1 malocclusion

Answer 13

Proclined upper anteriors
Retroclined lower anteriors
Localised anterior open bite or incomplete overbite
Narrow upper arch with the possibility of unilateral posterior crossbite.

Question 14

What are the management options for class II div 1 malocclusion?

Answer 14

Accepting the condition - if mildly increased overjet or if the patient is not unhappy
Attempting growth modification - with headgear or functional appliances
Simple tipping of teeth - using removable appliances
Camouflage
Orthognathic surgery

Question 15

Define functional appliances for growth modification.

Answer 15

Functional appliances for growth modification utilize, eliminate, or guide the forces of muscle function, tooth eruption, and growth to correct a malocclusion
They aim to produce restraint of maxillary growth and encourage mandibular growth.

Question 16

What are the therapeutic effects of functional appliances?

Answer 16

Dento-alveolar changes such as:
- distal movement of upper dentition
- mesial movement of lower dentition
- retroclination of upper incisors
- proclination of lower incisors.
May also be minor skeletal changes, although the degree of maxillary restraint and mandibular growth is usually small.

Question 17

Describe the potential benefits of early treatment for class II div 1 malocclusion

Answer 17

Improving appearance earlier
Reducing trauma risk
Better compliance with appliance wear

Question 18

Define baseplates in orthodontics.

Answer 18

Baseplates are used to provide support and anchorage for orthodontic appliances.

Question 19

What is the role of a flat anterior biteplane in orthodontic treatment?

Answer 19

To reduce overbite

Question 20

Describe when orthognathic surgery is typically performed

Answer 20

Orthognathic surgery is carried out when growth is complete.

Question 21

On what skeletal base class can you see a class II div 1 malocclusion?

Answer 21

Usually on a class II
Can see it on class I
Very rarely on class III but still possible

Question 22

How does a skeletal base most commonly cause a class II div 1 malocclusion?

Answer 22

Usually due to a retrognathic mandible

Question 23

What contributes to an overjet?

Answer 23

Skeletal pattern
Tooth inclination
Usually a combination of both

Question 24

What are the treatment principles of habits?

Answer 24

Stop habit - with reinforcement, removable appliance habit breaker or fixed appliance habit breaker
Allow spontaneous improvement
Treat residual malocclusion if required

Question 25

Using ARAB, design a URA to retrocline the anterior teeth

Answer 25

A - Roberts retractor 0.5mm HSSW with 0.5mm ID tubing
R - Adam’s clasps on 6s 0.7mm HSSW
A - mesial stops on 3s
B - self-cure PMMA and FABP (OJ+3mm)

Question 26

At what stage should functional appliances be used?

Answer 26

Early use (about 10) - 2 phase treatment of early functional appliance and fixed appliances in early permanent dentition
Later use - late mixed dentition or early permanent dentition, 1 phase treatment

Question 27

What are the potential disadvantages of early treatment with functional appliances?

Answer 27

Early skeletal effects not maintained in the long term
Treatment time increased
Research shows little difference between those treated early and later on

Question 28

What are the types of functional appliances?

Answer 28

Removable:
- tooth borne - either twin block or activator/bionator
- soft tissue borne - Franker (FR II)
Fixed:
- Herbst