Class II Div II Flashcards
What dental factors could lead to a class II div II malocclusion?
Acute crown-root angle
Thin labio-palatal thickness of teeth
Retrusive dentoalveolar processes of the maxilla & mandible
Comment on lower anterior face height (LAFH) and Frankfurt Mandibular Plane Angle (FMPA) for class II div II pts
LAFH and FMPA reduced with FMPA meeting after occiput
Define class II molar relationship
Buccal groove of the mandibular first permanent molar occludes posterior to the mesio-buccal cusp of the maxillary first molar
What is a common rotation of upper laterals if there is a class II div II malocclusion?
Mesio-labially rotated
Due to the presence of crowding
What does the red dot highlight in this image?
Prominent chin (progenia)
Asscociated with Class II Div II
How may a very high lower lip affect a patients teeth?
(Reduced LAFH)
A high lower lip will retrocline all upper incisors
(laterals sometimes escape this)
What is the aim of growth modification on class II div II patients?
How do we acheive this?
Convert malocclusion into a Class II div 1 by:
- Proclination of upper incisors
- Increase overjet
- Functional appliance (e.g. Twin block) to correct OverJet
- Usually finished with fixed appliances
Describe the growth of the mandible in a class II div II pt
Often associated with forward rotational growth pattern of the growing mandible
Define class II div II incisor relationship
Lower incisor edges occlude or lie posterior to the cingulum plateau of the upper central incisors with the upper central incisors are retroclined. The overjet is usually minimal but may be increased
What skeletal class is class II div II normally associated with?
Mild or moderate class II
Why do we treat class II div II pts?
Aesthetic concerns
Traumatic overbite
Crowding concerns
What are the treatment options for class II div II pts?
- No treatment
- Growth modification
- Camouflage
- Orthgnathic surgery
What teeth need to be removed for camouflage tx of patients with class II div II malocclusion?
For upper and lower
UPPER = extraction of 4s
LOWER= extraction of 5s (preferably non extraction)
How can the lips cause a class II div II malocclusion?
The lower anterior face height is reduced the lower lip will act higher on the upper incisors retroclining them. If the laterals are much shorter they may escape this action and be proclined
Retroclined = Pushed towards palate Proclined = Pushed away from palate
What would you expect to see clinically in a class II div II pt?
- Retroclined upper central incisors
- Upper lateral incisors are often crowded,mesio-labially rotated, normal or proclined, also diminutive
- Crowding is exacerbated by incisor retroclination (due to reduced arch length) -increased risk of canine impaction
- Increased overbite
(Reduced vertical dimensions in conjunction with a skeletal class II results in an absence of an occlusal stop to the lower incisors.
*Increased curve of Spee ) - Trauma: Lower incisors may occlude with upper incisors (damage to labial gingiva of lowers) or palate (damage to palatal mucosa)
Describe the typical angle of the Nasio-labial angle of a class II div II pt
Obtuse
What soft tissue characteristic is this which is seen in class II div II?
Deep labiomental fold due to the lower lip curling as a result of the reduced lower anterior face height
What ceph values would you expect to see on a class II div II patient
Increased ANB
Reduced gonial angle
Normal or reduced MMP angle and lower face height
Retroclined upper incisors
Depending on the aetiology B-point may be reduced or A-point may be increased
Why would we accept class II div II malocclusions?
*Acceptable aesthetics
*Patient not concerned
*Oral hygiene not good enough for treatment
*Explain the risks!
*Mouth guard - to prevent trauma
What would a functional appliance aim to to do in a class II div II pt?
Convert malocclusion into a Class II div 1 by:
*Proclination of upper incisors
*Increase overjet
*Functional appliance (e.g. Twin block) to correct OJ
*Usually finished with fixed appliances
Need same criteria as class II div I
What is the chance of replase in class ii div ii pts?
High tendency for any rotated upper laterals and the deep bite to relapse
Usually require long term retention
