Class II Division 1 Malocclusion

Question 1

What is the definition of Class 2 Division 1?

Answer 1

Lower incisal edge lies posterior to the cingulum plateau of the lower incisors.
Upper incisors are proclined or of average inclination.
Increased overjet.

Question 2

What are the reasons for treating a class 2 division 1?

Answer 2

Risk of trauma
Aesthetics

Question 3

What size of overjet increases the risk of trauma to the upper incisors?

Answer 3

greater than 9mm overjet- twice as likely to suffer trauma.

Question 4

What is the most common reason for a class 2 skeletal pattern?

Answer 4

Retrognathic mandible.

Question 5

In a class 2 division 1, what skeletal class are patients?

Answer 5

Usually skeletal class 2, but some are class 1.

Question 6

Why might the overjet have occurred?

Answer 6

Skeletal issues- retrognathic mandible.
Tooth inclination- proclined uppers and retroclined lowers.
Combination of both.

Question 7

What are the soft tissue features of a class 2 division 1?

Answer 7

Incompetent lips
Lower lip trap

Question 8

How can you achieve an anterior oral seal?

Answer 8

Lip to lip seal by activity of circus-oral musculature.
Mandible postured to allow lips to meet

or

Lower lip drawn up behind upper incisors.
Tongue place forwards between incisors to lower lip

Question 9

What are the dental features of a class 2 division 1?

Answer 9

Increased overjet
Overbite varies
Can be well aligned (typical), crowded or spaced.
Drying of gingivae and exacerbation of any pre-existing gingivitis.

Question 10

What habits may be associated with a class 2 division 1?

Answer 10

Thumb sucking.

Question 11

What are the occlusal features of a digit sucking habit?

Answer 11

Proclined upper incisors
Retroclined lower incisors
Localised AOB or incomplete OB
Narrow upper arch +/- unilateral posterior cross bite.

Question 12

What are the management options for this malocclusion?

Answer 12

Accept
Attempt growth modification
Tipping of teeth
Camouflage
Orthognathic surgery

Question 13

When might you want to accept a class 2 division 1 malocclusion?

Answer 13

Overjet is mild
Overjet is significant but patient not unhappy

Question 14

If a patient decides to accept the underlying malocclusion, what must you make them aware of?

Answer 14

High risk of trauma to the teeth, should be advised to get a mouthguard.

Remind the patient that fi they choose to have treatment later on in life, then their treatment options may be more limited at that point.
- no functional appliance after the growth spurt.

Question 15

How might you attempt growth modification?

Answer 15

Headgear- try to restrain maxillary growth.

Functional appliance.

Question 16

What is a functional appliance?

Answer 16

Utilise, eliminate or guide the forces of muscle function, tooth eruption and growth to correct a malocclusion.

Aim to restrict maxillary growth and promote mandibular growth.

Question 17

How does a functional appliance work?

Answer 17

Mandible is postured downwards and forwards.

Acts to retrocline upper incisors, procline lower incisors, distalise upper teeth and mesialise lower teeth.

Call degree of maxillary restraint and mandibular growth- 1-2mm.

To achieve a class 1 molar relationship.

Question 18

What types of functional appliances exist?

Answer 18

Removable
- twin block
- Activator/bionator
- Frankel

Fixed
- Herbst

Question 19

When is the ideal time to use a functional appliance?

Answer 19

During the pubertal growth spurt

Early use- about 10 years old and then have fixed appliances once all permanent teeth in the mouth.

Late use- late mixed or early permanent dentition.
Females- 11-13
Males- 13-15

Question 20

What are the advantages and disadvantages of using a functional appliance early (10 years old)?

Answer 20

Advantages-
- Risk of trauma is reduced earlier
- Psychological improvement- not going to be mad fun off.
- Better compliance with appliance wear

Disadvantages-
- Treatment takes longer
- Early skeletal effects from functional appliance or headgear therapy not maintained in long term.

Question 21

What type of treatment os required after a functional appliance?

Answer 21

Fixed appliance.

Question 22

When might you consider a URA for a class 2 division 1?

Answer 22

Very mild class 2 or class 1 skeletal relationship
Overjet due to proclination and spaced incisors
Overbite favourable

Question 23

What removable appliance design might you employ for this malocclusion?

Answer 23

ARAB

A- Roberts retractor with 0.5mm in tubing
R- Adams clasp 16 and 26 0.7mm HSSW.
A- Mesial stops on 13 and 23
Baseplate- Flat anterior bite plane, self-cure PMMA from 7-7.

Question 24

What is orthodontic camouflage?

Answer 24

Correcting the malocclusion by moving the teeth in a more controlled way using fixed appliances.

Question 25

When might you want to use orthodontic camouflage?

Answer 25

Malocclusion is not severe
Patient is only concerned about the position of the teeth.

Question 26

During orthodontic camouflage, if the goal is to reduce the overjet, what might you have to do first as part of the treatment plan?

Answer 26

Upper arch extractions- usually upper first premolars but depends on prognosis of other teeth and how much space if required.

Question 27

Why might a clinician decide that orthographic surgery is the best option for a class 2 division 1 malocclusion?

Answer 27

Skeletal discrepancy is severe in A/P and/or vertical direction.
Patient has stopped growing.

Question 28

In terms of orthographic surgery, when will fixed appliances be required?

Answer 28

Before, during and after surgery.