Anterior Open Bite Flashcards
AOB
Absence of vertical overlap of the upper and lower incisors
Incidence
2-4% children
4% adults
Significance
Dental appearance
Functional difficulties: eating/speech
Weak association with TMJ dysfunction
Skeletal causes associated with long face and poor facial appearance
Aetiology
Skeletal (genetic/TMJ Trauma)
Habits (Thumb sucking)
Soft tissues (Macroglossia/endogenous tongue thrust)
Latrogenic (extrusion of molars during treatment)
Classification
Dental
Skeletal
Combination
I/O Features
No unusual E/O features
Limited to incisor region
Features may be related to aetiology e.g., retroclined lower incisors and proclined upper incisors
Arch may be narrow
Dental AOB
Limited to incisor region
Asymmetrical
Retroclination of lower incisors
Skeletal AOB: I/O Features
7s may occlude
Incisors usually normal
Upper occlusal plane canted upwards
Lower occlusal plane canted downwards
Gingival hypertrophy due to mouth breathing
Skeletal AOB: E/O features
Long face
Inc MM angle
Lip incompetence
Cephalometric features
Dental AOB:
Normal skeletal pattern
Skeletal AOB:
Reduced ramus height
Increased MM angle
Increased lower facial proportions
Why tx
Dental aesthetics
Function
Facial appearance
Tx options
Interceptive
Orthodontics
Orthodontics and orthognathic surgery
Tx with FA only
Pts with acceptable facial profile
Specialist ortho
FA with elastics to extrude incisors
High pull headgear to intrude upper molars
TAD intrusion of buccal segments
Tx with Ortho and surgery
for pts with poor facial appearance (eg long lower face)
wait until growth has stopped
ortho and max fax surgeon
FA to align arches
Le Fort I maxillary impaction to elevate upper posterior teeth
Prognosis
Prognosis good if habits stops
1/3 of fixed appliance AOB cause relapse
Growth is unpredictable and may be unfavourable
Surgical correction in adults is usually stable
