Class II Div I Flashcards
BSI classification of Class I
Lower incisor edges occlude with or lie immediately below the cingulum plateau of the upper incisors
BSI Classification of Class II
Lower incisor edges lie posterior to the cingulum plateau of the upper incisors
BSI Classification of Class II Div I
Lower incisor edges lie posterior to the cingulum plateau of upper incisors
Upper incisors are proclined or of average inclination + increase in OJ
BSI Classification of Class II Div II
Lower incisor edge lie posterior to the cingulum plateau of upper incisors
Upper centrals are retroclined
OJ is reduced but can be increased
BSI Classification of Class III
Lower incisor edge lie anterior to the cingulum plateau of the upper incisors
OJ is reduced or reversed
What is the class II skeletal pattern of Class II Div I commonly due to?
Retrognathic mandible
Average maxillary incisor inclination
110
What does SNA relate to?
Position of maxilla to anterior cranial base
What does SNB relate to?
Position of mandible to anterior cranial base
SNA-SNB =
ANB
Average mandibular incisor inclination
90
Average FMPA
27
Average LAFH: TAFH
55%
Why are lips often incompetent in Class II Div I
Prominent upper incisors and/or underlying skeletal pattern
List examples of sucking habits
Thumb
Fingers
Blanket
Lip
Occlusal features of thumb sucking habit
Proclined upper anteriors
Retroclined lower anteriors
AOB
Posterior xbite
Narrow arch
Habit treatment options
Do nothing
Stob habit
Removable appliance habit breaker
Fixed appliance habit breaker
Function of headgear
Attempt to restrain growth of maxilla horizontally and/or vertically
Growth modification treatment options
Headgear
Functional appliance
What type of incisal classification are functional appliances most used for?
Mostly Class II div I
How do functional appliances work?
Aim to restrain maxillary growth and encourage mandibular growth
Examples of functional appliances
Tooth borne
- Twin block
Fixed
- Herbst
What changes do functional appliances make?
Mostly dento-alveolar changes
Minor degree of skeletal changes
What age should we use functional appliances?
Early use - about 10yrs
Potential disadvantages of early treatment with functional appliances (2)
- Early skeletal effects from functional appliance/headgear may not be maintained long term
- Overall tx time increased 3 phase tx
Potential benefits of early treatment with functional appliances
- Improve appearance earlier (teasing + psychological benefit)
- Reduce risk of trauma
- Often better compliance with appliance wear
Draw a URA design for retroclining anterior teeth
AIM: please construct a URA to retrocline the anterior teeth
A: Roberts retractor 0.5mm ID tubing
R: 16+26 Adams clasps 0.7mm HSSW
A: Tick, stops medial to 3’s
B: FABP OJ+3mm
How does upper premolar XLA’s create space for an OJ reduction?
Premolars XLa
Mesial movement of posteriors
Distal movement of anteriors
How does non premolar XLA correct OJ?
Distal movement of 6s aided by XLA of 7s
What jaw does orthognathic surgery usually include?
Usually mandibular
When are fixed appliances required for Orthognathic surgery
Before surgery
During surgery
After surgery
Process of orthognathic surgery for Class II Div I
Maxillary impaction
Mandibular advancement
Process of orthognathic surgery for class III
Maxillary advancement
Mandible moved back
