Class 2 division 1 malocclusion Flashcards
Class 2 div 1 malocclusion - give BSI definition
- 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
class 2 div 1 incisor relationship prevalence
15-20%
Reasons for treating a class 2 div 1
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
Class 2 div 1 skeletal pattern
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
An overjet can be caused by…
skeletal pattern
- vertical
- no particular association with transverse problems
tooth inclination
or combination of both
Class 2 div 1 common soft tissue features
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
How to achieve an anterior oral seal in patients with incompetent lips or a lip trap
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
Class 2 div 1 dental features
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
sucking habits related to a class 2 div 1 incisor relationship
thumb
fingers
blanket
lip
combination
effect depends on duration and intensity
occlusal features of a sucking habit
proclined upper anteriors
retroclination of lower anteriors
localised anterior open bite or incomplete overbite
narrow upper arch
- may see unilateral posterior cross bite
habit treatment principles
stop habit
- reinforcement
- removable or fixed habit breaker appliance
allow spontaneous improvement
treat residual malocclusion if required
management options for class 2 div 1 malocclusion
accept
attempt growth modification
simple tipping of teeth
camouflage
orthognathic surgery
When would you accept a class 2 div 1? what considerations would you need to make?
mildly increased overjet
significant overjet but not unhappy
give advice regarding mouthguard
treatment options may be more difficult in the future
growth modification examples for class 2 div 1
headgear
- try and restrain growth of maxilla horizontally and/or vertically
functional appliance
How do functional appliances correct malocclusion?
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
types of functional appliance for class 2 div 1
removable:
tooth borne
- twin block
- activator/bionator
soft tissue borne
- Frankel (FR II)
fixed
- Herbst
Functional appliance - aim
to produce restraint of maxillary growth and encourage mandibular growth
functional appliance success depends on…
favourable growth
compliance of patient
functional appliances - effect
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
- RCT’s indicate that degree of maxillary restraint and mandibular growth is usually small - 1-2mm
- significant variation in response
When to use a functional appliance?
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
potential disadvantages of early use of a functional appliance
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
early functional appliance treatment - potential benefits
improve appearance earlier
- potential psychological benefit
- reduce risk of trauma
- often better compliance with appliance wear
briefly discuss the simple tipping of teeth for treating increased overjets
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
how are fixed appliances used to camouflage a class 2 div 1 if the goal is to reduce the overjet?
upper arch extractions may be required to give space
- or distal movement
orthognathic surgery indications
growth complete
severe skeletal discrepancy in A/P or vertical direction
orthognathic surgery requirements
usually involves mandibular surgery but may also involve maxillary surgery
fixed appliances required
- before
- during
- after surgery
