Class 2 division 1 malocclusion

Question 1

Class 2 div 1 malocclusion - give BSI definition

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

class 2 div 1 incisor relationship prevalence

Answer 2

15-20%

Question 3

Reasons for treating a class 2 div 1

Answer 3

aesthetic concerns
dental health concerns
- prominent incisors at risk from trauma especially if incompetent lips
- >9mm overjet twice as likely to suffer trauma
- >9mm overjet IOTN (dhc) = 5a

Question 4

Class 2 div 1 skeletal pattern

Answer 4

usually associated with class 2 skeletal pattern
commonly due to retrognathic mandible
- maxillary protrusion less common
can be seen with skeletal class 1
very rarely seen with skeletal class 3

Question 5

An overjet can be caused by…

Answer 5

skeletal pattern
- vertical
- no particular association with transverse problems
tooth inclination
or combination of both

Question 6

Class 2 div 1 common soft tissue features

Answer 6

lips often incompetent due to prominence of upper incisors and/or underlying skeletal pattern
lower lip trap can be etiological factor in increased overjet
if lips incompetent
- special effort needed to achieve anterior oral seal

Question 7

How to achieve an anterior oral seal in patients with incompetent lips or a lip trap

Answer 7

mandible postured to allow lips to meet
lower lip drawn up behind upper incisors with tongue placed forwards between incisors to lower lip
or
a combination of these

Question 8

Class 2 div 1 dental features

Answer 8

increased overjet
overbite varies
can see good alignment, crowding or spacing
habitually parted lips may lead to drying of gingiva and exacerbation of any pre-existing gingivitis

Question 9

sucking habits related to a class 2 div 1 incisor relationship

Answer 9

thumb
fingers
blanket
lip
combination
effect depends on duration and intensity

Question 10

occlusal features of a sucking habit

Answer 10

proclaimed upper anteriors
retroclination of lower anteriors
localised anterior open bite or incomplete overbite
narrow upper arch
- may see unilateral posterior cross bite

Question 11

habit treatment principles

Answer 11

stop habit
- reinforcement
- removable or fixed habit breaker appliance
allow spontaneous improvement
treat residual malocclusion if required

Question 12

management options for class 1 div 2 malocclusion

Answer 12

accept
attempt growth modification
simple tipping of teeth
camouflage
orthognathic surgery

Question 13

When would you accept a class 2 div 1? what considerations would you need to make?

Answer 13

mildly increased overjet
significant overjet but not unhappy

give advice regarding mouthguard
treatment options may be more difficult in the future

Question 14

growth modification examples for class 2 div 1

Answer 14

headgear
- try and restrain growth of maxilla horizontally and/or vertically
functional appliance

Question 15

How do functional appliances correct malocclusion?

Answer 15

functional appliances utilise, eliminate or guide the forces of muscle function, tooth eruption and growth to correct a malocclusion
mandible is postured downwards and forwards

Question 16

types of functional appliance

Answer 16

removable
tooth borne
- twin block
- activator/bionator
soft tissue borne
- Frankel (FR II)

fixed
- Herbst

Question 17

Functional appliance - aim

Answer 17

to produce restraint of maxillary growth and encourage mandibular growth

Question 18

functional appliance success depends on…

Answer 18

favourable growth
compliance of patient

Question 19

functional appliances - effect

Answer 19

mostly dento-alveolar changes
- distal movement upper dentition
mesial movement lower dentition
- retroclination of upper incisors
- proclamation of lower incisors

minor degree of skeletal changes
- RCT’s indicate that degree of maxillary restraint and mandibular growth is usually small - 1-2mm
- significant variation in response

Question 20

When to use a functional appliance?

Answer 20

should be used during growth
- coincide with pubertal growth spurt if possible

options
- early use (around 10 years old) - 2 phase treatment
- later use - late mixed or early permanent dentition - 1 phase treatment

Question 21

potential disadvantages of early use of a functional appliance

Answer 21

early skeletal effects not maintained in long term
overall treatment time increased - 2 phase treatment
- early functional appliance plus retention
- fixed appliances in early permanent dentition
research shows little if any difference in results between those treated early and those who waited until in permanent dentition

Question 22

early functional appliance treatment - potential benefits

Answer 22

improve appearance earlier
- potential psychological benefit
- reduce risk of trauma
- often better compliance with appliance wear

Question 23

briefly discuss the simple tipping of teeth for treating increased overjets

Answer 23

simple URA’s have a limited role in treatment
unless
- v mild class ii or class I
- overjet due to proclined and spaced incisors
- overbite favourable
- only then after a specialist assessment

Question 24

how are fixed appliances used to camouflage a class 2 div 1 if the goal is to reduce the overjet?

Answer 24

upper arch extractions may be required to give space
- or distal movement

Question 25

orthognathic surgery indications

Answer 25

growth complete
severe skeletal discrepancy in A/P or vertical direction

Question 26

orthognathic surgery requirements

Answer 26

usually involves mandibular surgery but may also involve maxillary surgery
fixed appliances required
- before
- during
- after surgery