Class II division 1 Flashcards
What is the BSI definition for Class II div 1 malocclusion?
- 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 inclincation
What would be the IOTN if the overjet is more than 9mm?
5a
with which skeletal pattern is class II div 1 associated with?
- Class II
- and less commonly Class 1
- Rarely with class 3
What is the overjet in class II div 1 due to?
- Skeletal pattern
- Tooth inclincation
- Combination of both
What 2 soft tissue features associated with Class II div 1?
- Incompentent lips
- Lower lip trap - factor in increased overjet
3 ways a patient with Class II div1 can achieve anterior lip seal?
- by activity of circum-oral musculature with posturing the mandible allowing lips to meet
- Lower lip drawn up behind upper incisor and tongue placed forward between incisors to lower lip
- Combination of these
3 dental factors associated with Class II div 1 ?
- Increased overjet
- Varying overbite
- Exacerbation of periodontal disease due to drying of gingivae from incompetent lips
What habits are associated with Class II div 1?
Sucking habits of
* Thumb
* Finger
* Blanket
* Lip
Describe the dental (occlusal) Features of sucking habit?
- Proclination of upper incisors
- Retroclination of lower incisors
- Localised anterior open bite or incomplete overbite
- Narrowing of upper arch ± unilateral posterior crossbite
3 Principles of treating habits?
- Stop habit
- Allow spontaneous improvement
- Treat residual malocclusion
3 ways to stop sucking habit?
- Reinforcement
- Removable appliance habit breaker
- Fixed appliance habit breaker
5 management options for Class 2 div1 ?
- Accept
- Attempt growth modification
- Simple tipping of teeth using URA
- Camouflage
- Orthognathic surgery
When would you accept in class 2 div 1?
- Mild overjet
- Patient not unhappy with overjet
How would you attempt growth modification in Class 2 div 1?
- Headgear
- Functional appliance
Describe how headgear works in class 2 div1?
Restrain the growth of the maxilla and encourage mandibular growth (horizontally or vertically )
Describe how a functional appliance work?
It utilize , eliminate or guide the forces of muscle function, eruption and growth to correct a malocclusion
How is a the mandible postured when a patient wears a functional appliance for treatment of class 2 div 1?
- Down and forward
What are the two types of functional appliances in class 2 div 1?
- Removable : tooth borne and soft tissue borne
- Fixed
2 examples of tooth borne removable functional appliances for class 2 div 1?
- Twin-block
- Activator and bionator
An example of soft tissue borne removable functional appliance for class div 1 ?
- Frankel ( FR II)
An example of a fixed functional appliance for Class 2 div 1?
Herbst
Explain four dento-alveolar changes that happens during growth modification in class 2 div 1 with a functional appliance?
- Distal movement of upper dentition
- Mesial movement of lower dentitoin
- Retroclination of upper incisors
- Proclination of lower incisors
Although there are very minor skeletal changes with functional appliances in class 2 div 1 , what can this change be?
1-2mm of maxillary restraint and mandibular growth
When is the best time to use a functional appliance?
During growth , coincide with pubertal growth
When would the early use of a twinblock be used ?
Age of 10 , would be two phase treatment of functional appliance then fixed appliance
When would the later use of twinblock be ?
Late mixed or permanent dentition (1 phase)
What is the disadvantages with using a twin block/headgear at age of 10 ( early use)
- Early skeletal effects of functional appliance would not be maintained long term
- 2 phase treatment (increased treatment time)
3 benefits of early treatment with functional appliance?
- Improve appearance preventing any negative psychological effects
- Reduce the risk of trauma
- Better compliance with appliance wear
When would the use of URA be beneficial in the treatment of overjets despite it having a limited role of treatment overjets in general? (3)
- Very mild class 2 or class 1
- Overjet due to proclined and spaced incisors
- Favourable overbite
Write a URA prescription of correct an overjet by retroclining anterior teeth ?
- Active - Roberts retractor 0.5mm in tubing
- Retention - Adams clasps 0.7 HSSW on 6s
- Anchorage - mesial stops in 3s
- Base plate : flat anterior biteplane
If you use fixed appliances to reduce the overjet , what is required before that?
- Extraction to provide space (usually 4s)
- or Distal movement of teeth
When would orthognathic surgery be indicated? 2
- When growth is complete
- Severe skeletal discrepancy in AP or vertical
When would fixed appliances be required when carrying out orthognathic surgery?
- Before surgery
- During surgery
- After surgery
