Class 2 Div 1 Flashcards
Definition of class 2 div 1
- lower incisor edge lies posterior to cingulum plateau of upper incisors
- increased overjet
- upper central incisors proclined or of average inclination
What % of malocclusion are class 1
67-72
What % of malocclusion are class 2 div 1
15-20
What % of malocclusion are class 2 div 2
10
What % of malocclusion are class 3
3
Why treat class 2 div 1?
- Aesthetics
- Dental health: trauma risk
What skeletal pattern are class 2 div 1 usually?
Class 2 due to retrognathic mandible- maxillary protrusion less common
Soft tissue features?
- lips often incompetent due to prominence of incisors and/or underlying skeletal pattern
- lower lip trap can be cause of increased overjet
- if lip’s incompetent then special effort needed to achieve anterior oral seal
How to achieve anterior oral seal?
3 separate ways
1. Lip to lip seal by activity of circum-oral musculature- mandible postured to allow lips to meet
2. Lower lip drawn up behind upper incisors- tongue placed forwards between incisors to lower lip
3. Combination of these
Dental factors of class 2 div 1?
- increased overjet
- overbite varies
- potentially good alignment, crowding or spacing
- molar relationship
- habitually parted lips may lead to drying of gingiva and exacerbation of any pre-existing gingivitis
What habit can cause class 2 div 1?
Sucking habit
Occlusal features of sucking habit?
Proclination of upper anteriors
Retroclination of lower anteriors
Localised AOB/ incomplete OB
Narrow upper arch +/- unilateral posterior crossbite
Management options of class 2 div 1
- Accept
- Attempt growth modification
- Simple tipping of teeth
- Canouflage
- Orthognathic surgery
What should u consider when thinking of accepting class 2 div 1
- mildly increased overjet
- significant overjet but patient not unhappy
- will tx options be more difficult in future?
- advice re mouthguard
2 ways in which u can attempt growth modification?
- Headgear- try and restrain growth of maxilla horizontally and/or vertically
- Functional appliance
How do functional appliances work?
- FAs utilize, eliminate or guide forces of muscle function, tooth eruption and growth to correct malocclusion
- mandible postured downwards and forwards
- aim to restrain maxillary growth and promote mandibular growth
- success depends on favourable growth and enthusiastic patient
- used mostly for class 2 div 1, can use for 2 div 2, limited use for div 3
Types of functional appliances?
- Removable:
- Tooth borne e.g. twin block, activator/bionator
- soft tissue borne- frankel - Fixed- herbst
When should functional appliances ideally be used?
Pubertal growth spurt
Can be used earlier - about 10 (2 phase tx)
Potential disadvantage of early treatment with FA?
- early skeletal effect from FA not maintained in long term
- 2 phase tx, longer tx time- 1st phase early functional appliance plus retention- 2nd phase- fixed appliance in early permanent dentition
Potential benefits of early Tx with FA
- improve appearance earlier (psychological benefit)
- reduced risk of trauma
- better compliance
How would u use a URA to tip teeth in class 2 div 1
Active: roberts retractor 0.5mm in tubing
Retention: Adams clasp 6/6 0.7mm HSSW
Anchorage: Mesial stops 3/3
Baseplate: FABP
How can camouflage help with class 2 div 1
- upper arch extraction to create space for OJ reduction
- non extraction OJ reduction and molar correction
Features of orthognathic surgery
- when growth is complete
- severe skeletal discrepancy in A/P and/or vertical direction
- mostly mandibular surgery
- fixed appliances required before, during and after surgery
