Orthodontics Open bite Cezar Edward

1. Anterior open bite and
posterior open bite
-Orthodontics-
By Cezar Edward

2. Definitions
• Anterior open bite (AOB): there is no
vertical overlap of the incisors
when the buccal segment teeth are in
occlusion .
More common POB
• Posterior open bite (POB): when the
teeth are in occlusion there
is a space between the posterior teeth.

3. Anterior open bite - Aetiology
• inherited and environmental factors
Skeletal + Soft tissues + Habits + Localized failure of development.
In many cases the aetiology is multifactorial.

4. 1 Skeletal pattern
• The individuals who have vertically facial growth more than
horizontally  the lower facial height is increased  interocclusal
distance will increased (interocclusal=btw Max & mand)  some
compensatory effects will occur ; some overeruption  BUT if it is
large it will result in OPENBITE
Lateral cephalometric radiograph of a
patient with a marked
Class II division 1 malocclusion on a Class
II skeletal pattern with
increased vertical skeletal proportions.
Note the thin dento-alveolar
processes.

5. Patient with increased vertical skeletal
proportions and an anterior open bite.

6. 2 Soft tissue pattern
• Dr Mudar Kamal said that : -there are 2 schools :-
1st school says that tongue (when the pt swallow) will cause ant.
Openbite … But 2nd school says that the pt had openbite and during
swallowing he uses his tongue to achieve an ant. Oral seal …
Dr. M Kamal said that 2nd school is better
patients with an anterior open bite due to a digit-sucking habit the lips are
often incompetent and a proportion will achieve an anterior seal by positioning
their tongue forward between the anterior teeth during swallowing. Individuals
with increased vertical skeletal proportions have an increased likelihood
of incompetent lips and may continue to achieve an anterior
oral seal in this manner even when the soft tissues have matured.

7. 3 Habits
-The effects of a habit depend upon its duration and intensity.
-the anterior open bite produced is asymmetrical (unless
the patient sucks two fingers) and it is often associated with a
posterior crossbite. Constriction of the upper arch is believed to be
caused by cheek pressure and a low tongue position.

8. After a sucking habit stops the open bite tends to resolve ,
although this may take several months. During this period the tongue
may come forward during swallowing to achieve an anterior seal. In a
small proportion of cases where the habit has continued until growth is
complete the open bite may persist.

9. 4 Localized failure of development
• This is seen in patients with a cleft of the lip and alveolus , although
rarely it may occur for no apparent reason.

10. 5 Mouth breathing
-It has been suggested that the open-mouth posture adopted by
individuals who habitually mouth breathe, either due to nasal
obstruction or habit, results in overdevelopment of the buccal
segment teeth. This leads to an increase in the height of the lower
third of the face and consequently a greater incidence of anterior open
bite.
-On balance, it would appear that mouth breathing per se does not
play a significant role in the development of anterior open bite in most
patients.

11. Management of anterior open bite
•  Removal the causes :- by habit breaking appliances “fixed or
removable “
• Headgear & myofunctional appliance
• Fixed ortho. Treatment.
•  surgery

12. Approaches to the management of
anterior open bite
• There are three possible approaches to management.
• 1-Acceptance of the anterior open bite
• 2-Orthodontic correction of the anterior open bite
• 3-surgery

13. Acceptance of the anterior open bite
• ( particularly if the AOB does not present a problem to the patient)
• mild cases
• where the soft tissue environment is not favourable, for example
where the lips are markedly incompetent and/or an endogenous
tongue thrust is suspected
• more marked malocclusions where the patient is not motivated
towards surgery

14. Orthodontic correction of the anterior open bite
If growth and the soft tissue environment are favourable, an
orthodontic solution to the anterior open bite can be considered. A
careful assessment should be carried out, including the
anteroposterior and vertical skeletal pattern, the feasibility of the
tooth movements required, and post-treatment stability.
Methods of intruding the molars
• High-pull headgear
• Fixed appliance mechanics
• Buccal capping on a
removable/functional appliance
• Repelling magnets
• Temporary anchorage devices (TADs)

15. cases
• In the milder malocclusions the use of high-pull headgear during
conventional treatment may suffice.
• In cases with a more marked anterior open bite associated with a
Class II skeletal pattern, a removable appliance or a functional
appliance incorporating buccal blocks and high pull headgear can be
used to try to restrain vertical maxillary growth.

16. A patient wearing a maxillary
intrusion splint and high-pull headgear. The
face-bow of the headgear slots into tubes
embedded in the acrylic of the occlusal
capping, which extends to cover all the
maxillary teeth.

17. #

19. In cases with bimaxillary crowding and proclination, relief of crowding
and retraction and alignment of the incisors can result in reduction
of an open bite. Stability of this correction is more likely if the lips were
incompetent prior to treatment but become competent following
retroclination of the incisors.

20. Surgery
This option can be considered once growth has slowed to adult levels
for severe problems with a skeletal aetiology and/or where dental
compensation
will not give an aesthetic or stable result. In some patients
an anterior open bite is associated with a ‘gummy’ smile which can
be difficult to reduce by orthodontics alone necessitating a surgical
approach.

21. Management of patients with increased
vertical skeletal proportions and reduced
overbite
• Space closure appears to occur more readily in patients with in -
creased vertical skeletal proportions.
• Avoid extruding the molars as this will result in an increase of the
lower facial height. If headgear is required, a direction of pull above
the occlusal plane is necessary, i.e. high-pull headgear. Cervical-pull
headgear is contraindicated.
• If overbite reduction is required, this should be achieved by intrusion
of the incisors rather than extrusion of the molars. For this reason
anterior bite-planes should be avoided.
• Avoid upper arch expansion. When the upper arch is expanded
the upper molars are tilted buccally which results in the palatal
cusps being tipped downwards ,If arch expansion
is required, this is best achieved using a fixed appliance so that
buccal root torque can be used to limit downward tipping of the
palatal cusps.
• Avoid Class II or Class III intermaxillary traction as this may extrude
the molars.

22. (a) Intra-oral view of a van Beek appliance; (b) extra-oral view showing
the high-pull headgear; (c) lateral cephalometric radiograph of the
patient prior to treatment; (d) lateral cephalometric radiograph of the
same patient 1 year later.

23. Posterior open bite
• aetiology is less well understood.
In some cases an increase in the vertical
skeletal proportions is a factor, although this is more commonly
associated with an anterior open bite which also extends posteriorly. A
lateral open bite is occasionally seen in association with early extraction
of first permanent molars , possibly occurring as a result of
lateral tongue spread.
eruption disturbances.
Affected teeth may erupt and then cease to keep pace with vertical
development becoming relatively submerged or may fail to erupt at all
Although these teeth are not
ankylosed they do not
respond normally to orthodontic
force and indeed usually
become ankylosed if traction is
applied. Extraction is the only
treatment alternative.

24. More rarely, posterior open bite is seen in association with unilateral
condylar hyperplasia, which also results in facial asymmetry. If this
problem is suspected, a bone scan will be required. If the scan
indicates excessive cell division in the condylar head region, a
condylectomy alone, or in combination with surgery to correct the
resultant deformity, may be required.

25. Thank u