Anterior openbite

Question 1

Definition of AOB

Answer 1

Absence of vertical overlap of
the upper and lower incisors

Question 2

Incidence of AOB

Answer 2

2-4 percent of children
4 percent of adults

Question 3

Significance of AOB

Answer 3

• Dental appearance
• Functional difficulties: eating and speech
• Weak association with TMJ dysfunction
• Skeletal causes associated with “long face’ and poor facial appearance

Question 4

Aetiology of AOB

Answer 4

Skeletal
Habits
Soft tissues
Iatrogenic

Question 5

Skeletal

Answer 5

Genetic
TMJ (trauma/pathology)

Question 6

Habits

Answer 6

Thumb sucking
Digit sucking

Question 7

Soft tissues

Answer 7

Macroglossia
???endogenous/adaptive tongue thrusting
Muscular dystrophy

Question 8

Iatrogenic

Answer 8

Extrusion/over eruption of molars during treatment or retention

Question 9

Classification of AOB

Answer 9

Dental
Skeletal
Combination of dental/skeletal

Question 10

Intra-oral features

Answer 10

• 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

Question 11

Due to a digit or dummy sucking habit?

Answer 11

Usually limited to an incisor region
Usually asymmetrical
Retroclincation of lower incisors
Proclination of upper incisors class II div 1

Question 12

Stats for children up to age 7 finger/ thumb sucking? And continue to age?

Answer 12

15 percent of children up to the age 7
(And 7.5 percent continue after age 7)

Question 13

Stats for dummy sucking? And after age 6?

Answer 13

50 percent of children
1 percent after age 6

Question 14

For finger and thumb sucking severity of AOB depends on?

Answer 14

Duration and intensity of habit

Question 15

Thumb/ finger sucking for what amount of time would mean significant effects?

Answer 15

More than 6 hours a day

Question 16

Skeletal AOB intra-oral features?
Occlusion and occlusal plane?

Answer 16

In severe cases only 7s may occlude
Upper occlusal plane canted upwards
Lower occlusal plane canted downwards

Question 17

Skeletal AOB intra-oral features
Incisors etc.

Answer 17

Incisors usually normal inclinations
Gingival hypertrophy due to mouth breathing

Question 18

Extra oral features of skeletal AOB?

Answer 18

Long face
Increased MM angle
Lip incompetence

Question 19

AOB cephalometric features?
Dental AOB

Answer 19

May have normal skeletal pattern

Question 20

Ceph features skeletal AOB

Answer 20

Reduced ramus height
Increased MM angle
Increased lower facial proportion

Question 21

Treatment of AOB- why?

Answer 21

Dental aesthetics
Function
Facial appearance

Question 22

Treatment options

Answer 22

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

Question 23

Photo ‘goalpost appearance’

Question 24

Transpalatal arch

Question 25

Fixed appliance only treatment- Patients and best treated by?

Answer 25

Acceptable facial appearance Specialist orthodontists only

Question 26

Appliance wise how for fixed only

Answer 26

* Fixed appliances with elastics: extrude incisors * High pull headgear to intrude upper molars * Temporary anchorage device (TAD) intrusion of buccal segments

Question 27

Treatment with orthodontics and surgery Patients, when and best treated by?

Answer 27

* For patients with poor facial appearance (usually long lower face) * Wait until growth has stopped * Orthodontist & Maxillofacial Surgeon

Question 28

Appliance wise how with orthodontics and surgery?

Answer 28

* Fixed appliances to align arches * “Le Fort I” maxillary impaction to elevate upper posterior teeth

Question 29

Prognosis- stability and correction of AOB Prognosis and relapse

Answer 29

* If due to a habit, prognosis is good if habit stops * A third of fixed appliance AOB cases relapse

Question 30

Growth and surgical correction AOB?

Answer 30

* Growth is unpredictable and may be unfavourable * Surgical correction in adults is usually stable

Question 31

Most common cases of AOB are

Answer 31

Skeletal pattern and habits

Question 32

Treatment depends on

Answer 32

cause, and whether or not the facial appearance is acceptable

Question 33

Dental AOB and mild skeletal AOB may often be treated with

Answer 33

Fixed appliances

Question 34

Moderate and severe skeletal AOB usually needs

Answer 34

Surgery for full correction