Anterior openbite Flashcards
Definition of AOB
Absence of vertical overlap of
the upper and lower incisors
Incidence of AOB
2-4 percent of children
4 percent of adults
Significance of AOB
- Dental appearance
- Functional difficulties: eating and speech
- Weak association with TMJ dysfunction
- Skeletal causes associated with “long face’ and poor facial appearance
Aetiology of AOB
Skeletal
Habits
Soft tissues
Iatrogenic
Skeletal
Genetic
TMJ (trauma/pathology)
Habits
Thumb sucking
Digit sucking
Soft tissues
Macroglossia
???endogenous/adaptive tongue thrusting
Muscular dystrophy
Iatrogenic
Extrusion/over eruption of molars during treatment or retention
Classification of AOB
Dental
Skeletal
Combination of dental/skeletal
Intra-oral features
- Generally no unusual extra-oral features
- Usually limited to incisor region
- Features may be related to aetiology (eg. retroclined lower incisors and proclined upper incisors)
- Upper arch may be narrow
- Often due to Digit/Dummy
sucking habits
Due to a digit or dummy sucking habit?
Usually limited to an incisor region
Usually asymmetrical
Retroclincation of lower incisors
Proclination of upper incisors class II div 1
Stats for children up to age 7 finger/ thumb sucking? And continue to age?
15 percent of children up to the age 7
(And 7.5 percent continue after age 7)
Stats for dummy sucking? And after age 6?
50 percent of children
1 percent after age 6
For finger and thumb sucking severity of AOB depends on?
Duration and intensity of habit
Thumb/ finger sucking for what amount of time would mean significant effects?
More than 6 hours a day
Skeletal AOB intra-oral features?
Occlusion and occlusal plane?
In severe cases only 7s may occlude
Upper occlusal plane canted upwards
Lower occlusal plane canted downwards
Skeletal AOB intra-oral features
Incisors etc.
Incisors usually normal inclinations
Gingival hypertrophy due to mouth breathing
Extra oral features of skeletal AOB?
Long face
Increased MM angle
Lip incompetence
AOB cephalometric features?
Dental AOB
May have normal skeletal pattern
Ceph features skeletal AOB
Reduced ramus height
Increased MM angle
Increased lower facial proportion
Treatment of AOB- why?
Dental aesthetics
Function
Facial appearance
Treatment options
Interceptive”: stop digit sucking habits
- Orthodontics only: mild cases, dental AOB
- Orthodontics and Orthognathic surgery:
severe cases, skeletal AOB - Cases with a greater skeletal element are more difficult to treat
Photo ‘goalpost appearance’
Transpalatal arch
Fixed appliance only treatment-
Patients and best treated by?
Acceptable facial appearance
Specialist orthodontists only
Appliance wise how for fixed only
- Fixed appliances with elastics: extrude incisors
- High pull headgear to intrude upper molars
- Temporary anchorage device (TAD) intrusion of buccal segments
Treatment with orthodontics and surgery
Patients, when and best treated by?
- For patients with poor facial appearance (usually long lower face)
- Wait until growth has stopped
- Orthodontist & Maxillofacial Surgeon
Appliance wise how with orthodontics and surgery?
- Fixed appliances to align arches
- “Le Fort I” maxillary impaction to elevate upper posterior teeth
Prognosis- stability and correction of AOB
Prognosis and relapse
- If due to a habit, prognosis is good if habit stops
- A third of fixed appliance AOB cases relapse
Growth and surgical correction AOB?
- Growth is unpredictable and may be unfavourable
- Surgical correction in adults is usually stable
Most common cases of AOB are
Skeletal pattern and habits
Treatment depends on
cause, and whether or not the facial appearance is acceptable
Dental AOB and mild skeletal AOB may often be treated with
Fixed appliances
Moderate and severe skeletal AOB usually needs
Surgery for full correction
