Copy of biomechanical considerations and management of open bite

Biomechanical
considerations and
Management of open bite:
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


DEFINITION
Description of open-bite differ among various
authors and investigators
1.

2.

3.

Open-bite to be present when there is less than an
average overbite.
Open-bite to be present when there is edge-to edge
relationship.
Open-bite to be present when there is definite
degree of openness must be present.


1.

The degree of openness can vary from patient to
patient, but an edge-to-edge relationship or some
degree of overbite cannot be rightfully categorized
as an open-bite.

2.

The loss of contact, in the vertical direction, of
segments of teeth can occur between the anterior
segments or between the buccal segments.


The Glossary of Orthodontic Terms defines open
bite as a developmental or acquired malocclusion
whereby no vertical overlap exists between
maxillary and mandibular anterior or posterior
teeth.


Problems Posed by Open Bite
Open bite creates significant problems such as

•
•
•
•
•
•
•

TMJ disorders
Difficulty in speech (dysphonia)
Functional imbalance
Bad aesthetics
Alteration of incisor guidance
Reduction of normal functional activity

Etiology
•

Can be classified in to
• Genetic
• Environmental


1.Genetic factors
•

•

•

The genetic component of an open bite is related
primarily to the patient’s inherent growth potential.
It has been shown that growth patterns are
established early in life & maintained in the majority
of the individuals. Therefore, a skeletal open bite
could be evident in the early mixed dentition.
So control of the vertical growth pattern is difficult
by orthodontic means alone. However, changes in the
dentoalveolar complex may directly affect the most
representative skeletal features of an anterior open
bite.

2.Environmental Factors
1.

1.

Abnormal function
•
Thumb or digit sucking habit
•
Tongue thrusting habit
Improper respiration
Mouth breathing


3.
4.
5.
6.
7.
8.

Macroglossia
Neuromuscular deficiencies
Condyle trauma
Trauma of dentition
Degenerative diseases
Amelogenesis imperfecta


1.

•

Abnormal function
Thumb or digit sucking habit
•
This is one of the most common habits seen in
children.
•
The habit is quite reversible till the age of 3or4
•
Beyond this age, this habit becomes the cause of
many malocclusions.


•

It was noted Cineradiographically that, during strong
thumb sucking , the tongue was pressing forcibly
against the thumb & lingual surface of the mandibular
incisors. Not only this creating a proclination of the
mandibular incisors, but the tongue via the
glossopalatine muscle, was pulling the soft palate
downward & forward. This explains the increased
posterior height of the nasomaxillary complex.


•

The ramal muscles stabilize the mandible, preventing
excessive pressure on the intruded thumb &, of
course, keep the mandible disarticulated, permitting
the suprahyoids to place downward & backward
forces on the body and symphysis, and it probably
explains the bending of the body relative to the
ramus.


•

Tongue thrust habit
• Infantile / visceral swallowing is the physiological
basis for the neonate/infant to create a proper lip
seal during suckling. When the deciduous teeth
erupt, the pattern of swallowing changes to
adult/mature swallow. If the visceral swallow
persists after the 4th year of life, the habit is called
retained infantile swallow or tongue thrust.


Etiology of tongue thrust
1.
Genetic factors
2.
Learned behaviour
3.
Maturational factors
4.
Mechanical restrictions
•
Macroglossia
•
Constrictive dental abscess
•
Adenoid hypertrophy
•
Neurological disturbances
•
hyposensitive palate
•
Moderate motor disability
1.
Psychogenic factors

2.

•

Improper respiration
Mouth breathing habit
The mode of respiration influences the posture of
the jaws, the tongue and to a lesser extent, the
head. Hence mouth breathing can result in
altered jaw and tongue posture thereby altering
the oro-facial equilibrium leading to
malocclusion.


Classification of mouth breathers
1.
Obstructive
•
Complete or partial obstruction of the nasal
passage
1.
Habitual
•
Unconsciously performed act whereby
breathing occurs despite removal of
obstruction
1.
Anatomic
•
Lip morphology does not permit complete
closure of the mouth

3.

Macroglossia
Can be responsible for splaying the ant. teeth, thus
causing an open bite. (Certain features noted during
the clinical examination that are indicative of
macroglossia are spacing & flaring of the anterior
teeth, indentations on the lateral borders of the
tongue & lateral extension of the tongue onto the
occlusal surface of the lower teeth)

4.

Neuromuscular deficiency (eg. Muscular
dystrophy)
patients with this neuromuscular disorder cannot
properly use their masticatory muscles to close
their jaws. As a result the posterior buccal
segments tend to supra-erupt , leading to an
anterior open bite.

5.

Condyle trauma
Results in arrested condyle growth or ankylosis of
the condyle which leads to altered vertical growth
of the mandible, clinically evidenced as an anterior
open bite.

6.

Trauma to dentition
Particularly the incisors, can result in an anterior
open bite if the damaged teeth becomes ankylosed
before the pt finishes growing.

7.

Degenerative diseases
Involving the condyles may develop anterior open
bite. Idiopathic condylar resorption & Juvenile
rheumatoid arthritis are two pathologic conditions
that involve condylar resorption. Clinically, an
anterior open bite is evident as the disease
progresses.


8

Amelogenesis
imperfecta
As the teeth are rough
& sensitive, patients
tend not to bring them
together which permit
elongation of the
posterior teeth
resulting in anterior
open bite.


Classification
•

Open bite is classified on the basis of :

•

Region involved

Anterior
Posterior

Etiology

Dental
Skeletal

positional

Molar relation

Cl-I
Cl-II
Cl-III

dimensional


Clinical
evaluation

Simple
Complex
Compound/
Infantile
Iatrogenic

1.

An overjet combined with an open bite of less than
1mm can be designated as pseudo-open bite
problems.

2.

A simple open bite exists in cases in which more
than 1 mm of space may be observed between the
incisors, but the posterior teeth are in occlusion.

3.

A complex open bite designates those cases in
which the open bite extends from the premolars or
deciduous molars on one side to the corresponding
teeth on the other side.


4.

5.

The compound or infantile open bite is completely
open, including the molars.
The iatrogenic open bite is the consequence of
orthodontic therapy, which produces atypical
configurations because of appliance manipulation
or adaptive neuromuscular response.


Overview of Open Bite
•

ESTHETIC CONSIDERATIONS

1.

Balance between the nose, lips, and chin profile is
essential for optimal esthetics.
The dentoalveolar open bite malocclusion is
esthetically unattractive particularly during speech
when the tongue is interposed between teeth and the
lips.
The lower facial third is elongated in patients with
skeletal open bite.

2.

3.


•

FUNCTIONAL CONSIDERATION

1.

Tongue posture and function should be primary
considerations in Open-bite problems.

•

Acc. To Proffit “if a patient has a forward
resting posture of the tongue, the duration of
this pressure, even if very light could affect
tooth position vertically or horizontally”.


2.

•

Differentiation between primary causal and
secondary adaptive or compensatory tongue
dysfunction is essential.
Acc. to Proffit “A tongue thrust swallow is a
useful physiologic adaptation if you have an open
bite, which is why an individual with an open bite
also has a tongue thrust swallow” (i.e. Secondary
adaptive tongue dysfunction)


•

According to Bahr and Holt, four varieties of
tongue thrust may be differentiated

1.

Tongue thrust without deformation:- Despite the
abnormal function, no deformations ensues.

2.

Tongue thrust causing anterior deformation:- i.e
anterior open bite, sometimes coupled with
bilateral narrowing of the arch and a posterior
crossbite. Moyers (1964) terms this a simple open
bite.

3.

4.

Tongue thrust causing buccal segment
deformation:- A posterior open bite is often
seen clinically.
Combined tongue thrust:- causing both an
anterior and a posterior open bite, is another
common dysfunction. This is called a
complex open bite by Moyers and is more
difficult to treat.

According to Rakosi, four varieties of open bite due to
tongue posture may be differentiated:

1.

Anterior Open Bite
Open bite in a
deciduous dentition,
caused by a tongue
dysfunction as a
residuum of a sucking
habit.


•

Habitual position
The tongue positioned
forward during
functioning, thus
impeding the vertical
development of the
dentoalveolar structures
around the upper and
lower anterior teeth.


2. Lateral Openbite
Occlusion, In this type
of open bite the
occlusion on both sides
is supported only
anteriorly and by the
first permanent molars.


•

•

Habitual Position
The tongue thrusts
between the teeth laterally.
The tongue dysfunction
occurs in conjunction with a
disturbance in the
physiologic growth
processed around the first
and second deciduous
molars.


3. Complex open bite:
• Severe vertical
malocclusion. The teeth
occlude only on the
second molars.
•

Habitual Position
Tongue-thrusting occurs
during function.

4. Tongue dysfunction
and malocclusion:
• In mandibular
prognathism, the
downward forward
displacement of the
tongue often causes an
anterior tongue-thrust
habit.

INFLUENCE OF NASORESPIRATORY
FUNCTION
1.

2.

Physiologic adaptations to various types of upper
respiratory obstruction (e.g. constricted external
nares, deviation septum, nasal polyps, enlarged
adenoids, ) initially may lead to altered functional
activity of the muscles associated with respiration.
It is hypothesized that this change in the level of
postural activity of certain craniofacial muscles
ultimately may lead to a change in craniofacial
morphology, particularly in the vertical dimension

3

4.

5.

Changes in level of activity of certain
craniofacial muscles leads to an extension of
the head and airway maintenance.
This alteration causes a stretching of the
masticatory and facial muscles as well as the
associated soft tissue.
The possible relationship between airway
obstruction and aberrant craniofacial growth
is the type of patients descried as having
‘adenoid facies.’

6.

These patients typically present a mouth- open
posture, a small nose with button like tip, nostrils
that are small and poorly developed, a short upper
lip, prominent maxillary incisors, a trapping lower
lip, and a vacant facial expression.

7.

‘Mouth-breathing” individuals classically have
been described as possessing a narrow, V-Shaped
maxillary arch, a high palatal vault, proclined
maxillary incisors, and a Class II occlusion.


Adenoid Facies
Chronically
restricted nasal
respiratory function


Cephalometric Criteria
A proper cephalometric analysis enables a classification
of open bite malocclusions:
1.
2.

Dento Alveolar Open Bite.
Skeletal Open Bite.
1.
2.

3.
4.

Positional deviations.
Dimensional deviations

Skeletal Class II Open Bite
Skeletal Class III Open Bite

Dentoalveolar open bite
The extent of the
dentoalveolar open bite
depends on the extent of
the eruption of the teeth.
Eg: Supraocclusion of the
molars and infraocclusion
of the incisors can be
primary etiologic factors.


In vertical growth
patterns the
dentoalveolar
symptoms include a
protrusion in the upper
anterior teeth with
lingual inclination of
the lower incisors.


In horizontal growth
patterns, tongue posture
and thrust may cause
proclination of both
upper and lower
incisors.


A lateral open bite may
be considered
dentoalveolar in
combination with infraocclusion of molar
teeth.


Skeletal Open-Bite
1.

2.

3.

Characterized by excessive
anterior face height.
The major diagnostic criteria,
either or both of which may be
present , are a short mandibular
ramus & a rotation of the palatal
plane down posteriorly.
The typical growth pattern
shows vertical growth of the
maxilla (more posteriorly),
coupled with downwardbackward rotation of the
mandible and excessive
eruption of maxillary &
mandibular teeth.

4

5

Only two-thirds of this patient group actually have
open bite – in others excessive eruption of incisors
keeps the bite closed(compensatory dental eruption)
-but the rotation of the mandible produces cl II
malocclusion even if the mandible is normal size &
severe cl II, if the mandible is small.
Indeed, the facial disfiguration seen in skeletal open
bites can be found without the presence of dental
open bites; however, most instances, skeletal open
bite is combined with dental open bite

6.

7.

Because of the short ramus and the lower palate, the
pharyngeal space is constricted. In order to breathe,
these persons keep their tongues forward. Further
enhanced by the dental open-bite, there is a tonguethrusting tendencies.
Extreme skeletal open bite often are associated with
craniofacial malformations, such as the Crouzon’s
syndrome patient, in whom there are gross
imbalances in skeletal structures in all three
dimensions of the face


8.

In 1964 Sassouni described the skeletomuscular
differences between the skeletal open bite &
skeketal deepbite


•

Skeletal
deepbite(hypodivergent):
The vertical chain of
masticatory muscles, (the
masseter & internal
pterygoid,) course is
essentially a vertical path
with the short, thick bellied
muscle masses well ahead
of molar resistance thus
serving to keep buccal
segments depressed &
promoting a horizontal
growth of skeletal pattern.


•

•

Skeletal open bite
(hyperdivergent):
The same sling of vertical
musculature as being long &
spindly and coursing
obliquely downward &
backward. The mass of
muscle is well behind the
molar resistance thus it does
not serve to keep the buccal
depressed & hence
promotes vertical
development.


Skeletal Open-Bite

1.Positional
deviations

2.Dimensional
deviations.


1.Positional Deviations
Acc to Sassouni…
1.
The four bony planes
of the face are steep to
each other, bringing
the center 0 close to
the profile.


2

The anterior arc,
therefore follows the
convexity of the
profile.


3.

The posterior vertical
chain of muscles is
arcuate, and the
masseter muscle is
posterior to the buccal
teeth, thus creating a
mesial component of
forces responsible for
the dental protrusion.

4.

The cranial base angle and the gonial angle are
obtuse.


2.Dimensional deviations
1.

The total posterior
facial height (S-Go)
tends to be half the
size of the anterior
total facial height (NMe).


. The Lower Anterior
Facial Height exceeds
the Upper Anterior
Facial Height.

2


3

The facial breadths
tend to be narrow,
giving a long, ovoid
appearance in the
frontal view.


. The ramus is short with
an antegonial notch at
its lower border.
5. The mandibular
symphysis is narrow
anteroposteriorly and
long vertically.
4


6.

7.

There is a lack of mental protuberance
development..
The palatal vault is high and narrow.


Skeletal Class-II Open bite
1.

2.

3.

This combination is primarily an open-bite type,
positionally and dimensionally.
The major variant here is in the anteroposterior
dimensions of the jaws. The maxilla may be longer,
and the mandible shorter.
The differential evaluation of these two possibilities
is important, as the prognosis and the treatment
approach may be different.

4.

In some instances, the
rotation of the
mandible may be
purely positional.
Often this is due to a
downward and
backward rotation of
the mandible.


5.

This rotation is associated with excessive extrusion
of the molars. If these interferences were removed,
the mandible could be permitted to rotate in a
closing direction, improving the Class II and the
open-bite patterns simultaneously.


Skeletal Class-III Open bite
1.

This combination
consists primarily of
an open-bite with a
maxilla deficiency or
a large mandible.


•

Among the facial deformities, these have probably
the worst prognosis in terms of dentofacial
orthopedics.

•

If correction of this open-bite is attempted by
rotating the mandible in a closing direction, the
protrusion of the chin is increased.

•

On the other hand, the reduction of the mandibular
protrusion is attempted by rotating the mandible
downward and backward, the open-bite is increased.


Management
•

The timing of treatment and determination of growth
pattern are crucial. Based on type of dentition, the
management can be divided into
• Management in deciduous dentition
• Management in mixed dentition
• Management in permanent dentition


Management in deciduous dentition
1.

2.

3.

Dentoalveolar
Control of abnormal habits and elimination of
dysfunction should be given top priority in the
deciduous dentition.
The anterior open bite improves as soon as the
habit is stopped.
Treatment with screening appliances is indicated in
such open- bite cases. (Tongue crib or oral screen,
vestibular screen, reminder appliance, activator,
etc.)

•

•

•

Skeletal
A skeletal open bite is seldom observed in the
deciduous dentition. Habit control is of only
secondary consideration in these cases, retarding
the increasing severity of the dysplasia.
Phase I
Extra oral orthopedic appliances such as chin
caps can be used effectively to redirect growth.
Phase II
Habit control


•

Management of mixed dentition
•

Dentoalveolar
• Early mixed dentition
• Screening appliances and habit breaking appliances.
•

Late mixed dentition
• Multi-attachment fixed appliances (but a long
posttreatment retention phase is necessary until the
abnormal perioral muscle function can be reduced.)
• Swallowing exercises ( swallowing without
thrusting, putting the tip of the tongue behind the
upper & lower incisors) may reinforce the
establishment of a mature deglutitional & functional
pattern for the tongue.

Skeletal
•

•

•

•

Management depends on severity of
malocclusion and possibility of a dentoalveolar
compensation.
Growth pattern in this type of problem is almost
always vertical.
The inclination of the maxillary base plays a
vital role in the management. If the jaw bases
are divergent, the prognosis is poor.
If the maxillary base is tipped downward and
forward, functional appliance therapy may be
successful.

•

•

•

Intrusion of buccal segments & extrusion of the
incisors, mesial movement of the posterior teeth
is also a benificial dentoalveolar measure to
help close the bite.
Treatment can be undertaken with activators
combined with extraction and/or extraoral force
application.
In extreme vertical growth patterns if the lip
sealing ability is disturbed, surgical resection of
the mentalis muscle is performed to reduce the
‘golf ball’ chin effect. Schili insists on surgery
after eruption of lower canines to enhance
stability & bite closure.

•

•

Combined dentoalveolar
and skeletal
It is likely that most skeletal open bite case are at
least partially attributable to abnormal perioral
muscle function. So a combined treatment approach
is recommended.
Elimination of abnormal perioral function
•

•

Screening and habit breaking appliances, serial
extraction, activators, etc.

Improvement of the skeletal relationship
•

Fixed appliances.


Management in permanent dentition
•
•

•
•

Multi-attachment, fixed mechanotherapy
Screening appliances with active extrusive force
on incisors (tongue crib with active labial bow)
Repelling and attracting magnets
Functional appliances can play only subordinate
role- used in the retention phase to prevent over
eruption in the posterior segments


BREIF DISCUSSION OF
VARIOUS TREATMENT
MODALITIES
OF
OPEN BITE

Management of open bite can be majorly
classified as:
1 ORTHODONTIC
HABIT BREAKING APPL.

2

ORTHOPEDIC

MYOFUNCTIONAL

3

SURGICAL

FIXED THERAPY


ORTHODONTIC CORRECTION
HABIT BREAKING APPLIANCES

•

Tongue crib
•
Anterior open bite
•
A removal or fixed appliance can inhibit tongue
thrust.
The crib used with a removable appliance for an
anterior open bite consists of a palatal plate with a
horseshoe-shaped wire crib.
•

•

•

The crib is placed in the area of local tongue
dysfunction and resultant malocclusion.

•

•

•

Crib placed 3 to 4 mm
lingual to upper incisors
& it is made of 0.8mm
wire
If the crib is placed at
the gingival third, a
proper adjustment can
stimulate the eruption of
these teeth, a movement
needed in open bite
problems.
It should neither touch
the teeth nor disturb the
occlusion.

•

The acrylic also can be
interposed between the
teeth, covering the
occlusal surfaces of the
upper molars, to
prevent eruption of
these teeth and
enhance anchorage of
the plate, which is
especially beneficial in
open-bite problems.

•

•

•

•

The bite-block here can be 3 to 4 mm, which is
usually beyond the postural vertical dimension in
open-bite patients.
In such cases a stretch reflex is elicited from the
closing muscles that enhances the depressing action
on the buccal segments and helps close the anterior
open bite.
It can also incorporate an expansion screw, since
many open bite problems also have a narrow arch.
Thus the appl. combines inhibitory action via the
screen & mechanical action via the jackscrew, labial
bow, etc.

Posterior open bite
• The crib is placed 2-3 mm away
from the teeth & extends below the
occlusal surface sufficiently to
prevent tongue from inserting into
the interocclusal space during rest
position.
• Fixed tongue cribs are also used


•

Vestibular screen
•

•
•
•

An acrylic shield extending vertically from the
upper labial fold to the lower labial fold and
horizontally from the distal margin of the last
erupted molar on one side to that on the other
Edge to edge bite registered
Worn at night and 2 to 3 hours during daytime
Lip exercises along with the appliance


•

•

Properly made and worn, the appl. is effective in
eliminating abnormal sucking habits and lip
dysfunction.
It helps to establish a proper lip seal & indirectly
influences the posture of the tongue.
•

Modifications
•

•

Vestibular screen with breathing holes
(mouth breathing pts. who have difficulty
sleeping with the appl.)
Vestibular screen with tongue crib


Reminder appliances
• An acrylic plate in which a bead or a wire mesh
is embedded
• Reminds the patient not to go back to the habit
Other methods
• Psychological approach
• Parent counseling
• Patient counseling and motivation
• Dunlop’s Beta hypothesis
• Chemical approach
• Bitter tasting or foul smelling preparation
placed on the thumb or digit
•

•


MYOFUNCTIONAL
APPLIANCE

Activator
•

The bite is opened 4 to 5 mm to develop a
sufficient elastic depressing force and load the
molar that are in premature contact.

•

Properly constructed activators that follow this
principle can influence the vertical growth pattern.


•

To “close the V”
between upper and
lower dental arches by
depressing the posterior
maxillary segments with
the activator in a manner
analogous to that of
orthognathic surgery


Extrusion of incisors achieved by loading the lingual
surfaces above the area of greatest concavity and also
with the labial bow above the area of greatest
convexity.


•

A modification, the Elastic Activator similar to
Stockfish’s kinetor was used in the treatment of
anterior open bite by A. Stellzig et.al in 1999.
• The intermaxillary acrylic of the lateral occlusive
zones is replaced by elastic rubber tubes
• Intrusion of both upper and lower posterior teeth
by orthopedic gymnastics


Bionator
•

•

•

•

The open bite Bionator used to inhibit abnormal
posture and function of the tongue.
The construction bite is as low as possible, but a
slight opening allows the interposition of posterior
acrylic bite blocks for the posterior teeth, to prevent
their extrusion.
To inhibit tongue movements, the acrylic portion
of the lower lingual part extends into the upper
incisor region as a lingual shield, closing the
anterior space without touching the upper teeth.
The palatal bar has the same configuration as the
standard bionator.

Standard Bionator

Open bite Bionator


•

The labial bow differs
from the standard
appliance, that the wire
runs approximately
between the incisal
edges of the upper and
lower incisors.


•

The labial part of the bow is placed at the height of
correct lip closure thus stimulating, the lips to achieve
a competent seal and relationship.

•

The vertical strain on the lips tends to encourage
the extrusive movement of the incisors, after
eliminating the adverse tongue pressures.


Frankel Function Regulator
. FR IV is used in

correction of open
bite.
It has two buccal
shields, two lower lip
guards, an upper labial
wire, and four
occlusal rests.


•

Normally, anterior open bite problems show
protracted tongue posture with incompetence of lips.
The tongue tooth contact replaces the lip seal during
deglutition to create negative atmospheric pressure.

•

FR IV along with lip exercises (the anterior vertical
muscle chain being strengthened by lip seal
exercises) cause lips contact, reducing tongue
protrusion and cause the tongue to move back into its
normally raised position in proximity with palate,
during deglutition.


•

•

•

Incisors can then erupt normally to close the bite
while the tongue reestablishes an interocclusal
clearance between the posterior teeth.
This allows the mandible to close upward & forward
into a more favorable growth direction, reducing the
MP angle.
Modifications:
• FR-IV with chin cap.
• FR-IV with a tongue crib.


Twin block
•

•

•

•

The appl. is modified to achieve vertical control &
close the ant. open bite.
The lower appl. extends distally to the lower molar
region with clasps on the first molars & occlusal rests
on the second molar to prevent their eruption.
The acrylic slightly relieve contact with the lingual
surfaces of U/L ant. teeth so that they are free erupt.
A palatal spinner may be added to the upper appl. to
help control an anterior tongue thrust.


•

•

The bite is designed to register a 4mm interincisal
clearance .
It is necessary to accommodate blocks of sufficient
thickness, to make it difficult for the pt to disengage
the blocks.
• Modifications
• Headgear tubes can be attached and high pull
traction can be applied to a modified face bow
(concorde) for intrusion of molars
• Vertical elastics (Dr Christine Mills)
• Repelling or attracting rare earth magnets
(Dellinger)

Headgears
Centers of resistance in
midfacial complex.
1. Alveolar process.
2. Maxilla.


Direction of force
passes behind both
alveolar and skeletal
centers of resistance,
producing clockwise
rotation of maxilla and
maxillary dentition.


Direction of force
passes between alveolar
and skeletal centers of
resistance, producing
clockwise rotation of
maxilla and
counterclockwise
rotation of maxillary
dentition.


Direction of force
passes above both
alveolar and skeletal
centers of resistance,
producing
counterclockwise
rotation of maxilla and
maxillary dentition.


High pull HG
•

•

•

One approach to vertical excess problems is to
maintain the vertical position of the maxilla & inhibit
eruption of the max. posterior teeth – attempted by
high pull HG.
Worn 14 hrs a day with a force greater than 12
ounces/side.
But this is least effective as it does not control the
eruption of other teeth.


High pull HG to a max. splint
•

•

A more effective HG approach for children with
excessive vertical development.
But still does not control the eruption of the lower
teeth.


High pull HG to a functional appl. with
bite blocks
•

•

•

The most effective approach to growth modification
involving vertical excess & a cl-II relation.
The high pull HG improves retention of the
functional appl. & produces a force direction near the
estimated Cres. Of the maxilla
If the bite block separates the teeth more than the free
way space, a force is created against both U&L teeth
that opposes eruption.

Lloyd E Pearson
Describes seven different procedures for
treatment of open bite with backward rotating
mandible


Procedure - I
•

In the mixed dentition open-bite patient we could
intrude the upper first permanent molars and then
remove the remaining deciduous teeth, permitting
open-bite closure.

•

Occipital headgear with a transpalatal arch to
control the inclination of the molars as they are
intruded.

•

After the molars have been intruded perhaps 3 mm
the deciduous teeth are removed, the mandible is
hinged closed, and the anterior open-bite is closed.

•

The lower molars will often tend to extrude in this
type of situation, unless mechanics are designed to
control their eruption.

•

An addition of a vertical pull-chin cup to the
occipital headgear and transpalatal arch would
intrude the upper molars, while preventing the
eruption of the lower molars.

•

As the open bite closes the mandible hinges
upward, reducing the height of the lower face.


Vertical pull chin cup


Procedure -- II
•

Extraction of first premolars and use a vertical pullchin cup with (16 ounces of forces)

•

This can close the mandibular plane angle, reduce
the lower facial height and close anterior open bites.

•

Approximately 40 of closure of the mandibular plane
angle was found in his study.


•

Four possible mechanisms of (action at work)
1.

maxillary sutures are pressure sensitive and some
intrusion of the maxilla could occur.

2.

The posterior teeth tend to move forward mesially.

3.

A slight change in the shape of the condylar neck, with
many tending to be curved more forward than previously.

4.

A retardation of eruption of the posterior teeth.

Procedure -- III
•

Mandibular bite- block therapy, augmented with
vertical pull-chin cup therapy, can produce a
favorable holding of the vertical height throughout
the growth period, intrusion of posterior teeth

•

The hinging of the mandibular plane in a
counterclockwise direction and closure of anterior
open bites.


Procedure -- IV
•

Magnetic bite blocks.

•

Although we get rapid results, two difficulties arise
with bite blocks
a.

b.

Extreme mouth opening and patience to tolerate
the appliance.
lateral movement of the mandible, that can cause
some temporomandibualr joint strain.


Procedure -- V

•

Occipital headgear has proved useful and
generally seems effective in controlling the
vertical dimension in the maxilla.

•

Mandibular control appears to be more
difficult to manage.

Procedure -- VI
•

Another useful treatment modality is vertical
reduction genioplasty.

•

One advantage, is that it does not involve the
temporomandibualr joints.


•

It can be done after non-surgical treatment as an
adjunct to bring the chin up and forward, to
improve facial balance, and to achieve competency

•

A vertical reduction genioplasty might be more
useful in patients with the correct amount of
exposed gingiva in the maxilla because it does not
provide maxillary anterior intrusion.


Procedure -- VII
•

•

Maxillary impaction + vertical reduction
genioplasty, should also be considered.
This can be a great benefit to patients with
i.
ii.
iii.
iv.
v.

elongated upper posterior teeth,
elongated upper anterior teeth,
a gummy simile,
a tall lower face,
anterior maxilla with a maxillary impaction.


Fixed Mechanotherapy
1.

•

•

Extrusion of U & L incisors
This treatment strategy is appropriate if the pt has
an open bite with normal skeletal pattern
Different methods of extrusion
a) Extrusion arches - used in noncompliant pt.
b) Vertical elastics - used in compliant pts


a)

Extrusion arches

•

Used to correct U & L occlusal planes that diverge
ant. to the first PM.

•

Indications :
a) when spontaneous correction of an ant. open bite
does not occur following tongue crib therapy
b) when a constant extrusive force is desired in the
ant. teeth with minimal post. side effects


•

It is one-couple force system .

•

Wire used is




16 x 22 SS or 17 X25 TMA with 900 offset bend at the
molar.
Extrusive force of 100 gms for 4 incisors.


Mode of Action
•

At the Incisor:
Extrusion can involve single teeth or group of teeth.

•

When a group of teeth are to be extruded ,a segment
of heavy arch wire may be used in the brackets of the
anterior teeth, and the teeth are extruded as if they
were one big tooth.

•

Whether the extrusion arch is tied segmentally or to
continuous arch wire or placed directly into the
brackets, the effect is the same

At the Molar:
•
Intrusive force & a tip forward moment.
•
Relatively very minimal buccal flaring of the molar
is seen.


Proximal view


1.

2.

3.

To negate the tip forward moment of the molar :
Buccal segment from the upper first M to the first
PM is added.
The magnitude of the extrusive force should be kept
low.
Adding vertical elastics off the post. segment .


b)
i.
•

•

Vertical Elastics
Triangle Elastics:
Triangle elastics aid in the improvement of class I
cuspid intercuspation and increasing the overbite
relationship anteriorly by closing open bites in the
range of 0.5 to 1.5 mm.
They extend from the upper cuspid to the lower
cuspid and first bicuspid teeth.


ii.

Anterior Vertical Elastics:
Class II orientation

Class III orientation


Avoid Intermaxillary Elastics
1.

2.

3.

Intermaxillary elastics from the posterior teeth have
a vertical force vector which extrudes these teeth
and can further open the posterior vertical
dimension.
If class II or III elastics are required, they should be
attached posteriorly to premolars rather than
molars.
These ‘short elastics’ minimize the extrusive effect
on the back of the arch.

2.

Bracket Position

•

The placement point for incisor brackets may vary
in cases of infraocclusion.

•

In cases of open bite, placing anterior bracket 1 mm
more towards the gingival side.


3.

•

•

•

Multiloop Edgewise Arch
Wire (MEAW)
In order to accomplish correction of a
malocclusion, the dentition must be placed in a
proper 3-dimensional perspective; AP, vertically, &
bilaterally.
AP – the axial inclinations of all teeth must be
correct.
In open bite cases, the inclination is
characteristically mesial. The greater the openness
of the occulsal planes, the greater the inclination.

•

Multiloop Edgewise Arch Wire was developed
by Kim to achieve these goals :i

ii.

iii.

Correcting the inclination of the occlusal
planes.
Aligning the maxillary incisors relative to the
lip line.
Uprighting the axial inclinations of the
posterior teeth.


•

The MEAW contains horizontal and vertical loops
fabricated from a 16 x 22 ss wire in an L - shape
fashion

•

The vertical loops act as a break between the teeth,
lowers the load deflection rate and provides
horizontal control.

•

The horizontal loops further reduces the load
deflection rate and provides vertical control.


•

Typical tip back bends of 3-5degrees are given on
each tooth.

•

Elastics are placed between the loops that lie mesial
to opposing cuspids.

•

Recommended elastic size is 3/16 inch heavy, with
a force approximately 50 gms when the jaw is
closed, & 150gms at moderate opening.


•

The dentition must first be prepared for the use of this
mechanism by elimination all rotations, spaces,
crowding, or poorly positioned brackets.

•

Prepared upper MEAW wire has a deep curve of spee
& a lower a reverse curve. This wires will apply an
intrusive force on the incisors, which would have the
effect of worsening an openbite. This effect must
therefore be counteracted by an anterior vertical
elastic force


•

KIMS technique was later modified by AYHAN
ENACAR etal, using 16 x 22 reverse curve NiTi arch
wires with heavy intermaxillary elastics applied in the
canine region


4.The Tip-edge Technique
•

•
•

•

Kesling in 1986 designed the Tip-edge brackets
which are dynamic and upright teeth easily and
automatically with or without intermaxillary elastics.
No loops are required for uprighting.
Anteriorly placed class II elastics along small anchor
bends in the arch wire with Tip-edge brackets were
used to correct anterior open-bite.
Kim’s philosophy + Tip-edge brackets produced
stable results in a very short period of time.

5. Extraction Of Teeth
•

The various extraction modalities for the correction
of an open bite are tailored towards:

a)
b)

Extruding the ant. Segment
Moving the post. teeth anteriorly (wedge effect.

c)

Combination of the two.


Second Molar
extraction
•

Indicated in pts who have an open bite with contact
only on these teeth & divergent occlusal plane.

•

This method provides an advantage over the other
extractions , since no space closure is needed &
vertical forces are not likely to be generated.


First Molar extraction
•

If the second M have not erupted, & if the pt is only
contacting on the first M would eliminate the
increased vertical height and second M would only be
erupted up to the new established vertical height.
( A Kuhlberg, 2003 )


Extraction of PM
•

This treatment works very well in pts with occlusal
planes that diverge anteriorly from the PM.

•

Bite is closed with help of extrusion of the ant.
segment instead of the wedge effect.


6. Low transpalatal arch
•

It is believed that, tongue
pressure against the
transpalatal arch during
swallowing, especially
when the transpalatal
arch is placed low in the
palate, will inhibit
maxillary alveolar vertical
growth.


7.Low Mandibular Lip
Bumper
•

Cetlin and Hoeve advocated the use of a lip bumper
for the development of the lower dental arch.

•

They suggested that if the lip bumper were adjusted
low, the cheek and lip mucosa would rest above the
appliance, and this will inhibit vertical mandibular
molar dentoalveolar development.


8. ACTIVE VERTICAL
CORRECTOR
•

AVC is a simple
removable or fixed
orthodontic appliance
that intrudes the
posterior teeth of both
the maxilla and
mandible by reciprocal
forces.


•

By effective intrusion of posterior teeth, the mandible
is allowed to rotate in upward and forward directions.

•

The uniqueness of this appliance is that, it corrects
anterior open bite problems by actually reducing
anterior facial height.

•

Problems formerly thought to require orthognathic
surgery, can now be treated successfully with AVC.


Method of Action :•

Force system -- generated by repelling magnets,

•

AVC is considered superior to a static bite block
appliance energized only by the intermittent force
from the muscles of mastication.

•

The constant force system of the AVC results in
greater rapidity of tooth movement.

9. Skeletal Anchorage System
(SAS)
•
•

•

•

Skeletal anchorage system was developed for tooth
movements.
Mikako Umemori et al. in 1999 described the SAS
(Skeletal Anchorage System for open bite
correction).
SAS consists of titanium miniplates (SMAP- Super
Mini Anchor Plate Dentsply-sankin ) that are
temporarily implanted in the maxilla or the
mandible as an immobile anchorage.
These miniplates are fixed at the buccal cortical
bone around the apical regions of the lower first and
second molars on both the sides.

Advantages of SAS :
No serious side effects.
Simplified treatment mechanics.
Shortened treatment period.
Minimum discomfort.
Control of the level of occlusal plane.


SURGICAL CORRECTION
•

•

•

Hulliten in 1849, was the first to surgically correct an
ant. open bite.( Ant. Mand. Sub-apical Osteotomy ).
Cohn-stock in 1921, introduced Ant. Max. Osteotomy
which was modified by Wassmund, Wunderer &
Cupor.
Schuchardt introduced Post. Max. Osteotomy as a
two-stage procedure which was modified to a singlestage procedure by Kufner.


•

•

Limberg in 1925, introduced Closed Sub-condylar &
Open oblique Osteotomy.
The present-day surgical techniques to correct
open bite involves, Max. surgery for ant. extrusion &
post. intrusion, and Mand. surgery to elevate the
incisor segment. The choice of the appropriate
surgical technique requires careful diagnostic
evaluation


ANTERIOR MAX. & MAND. SUB-APICAL
OSTEOTOMY
•

•

INDICATIONS FOR MAXILLARY ASO
A small open bite with minimal tooth exposure, lip
incompetance , good naso-labial angle & adequate
lower ant.facial height.
An unaesthetic edentulous appearance due to
concealed maxillary incisors


INDICATIONS FOR MAND. ASO
•

•

Ant. open bite due to reverse curve in the mandibular
arch.
Transverse max.-mand. harmony & good aesthetic
balance between upper lip & max. ant. teeth.
After surgery the max. & mand. Ant. Segment
are immobilised for 5-6 weeks. Relapse potential is
very minimal.


•

•
•
•
•

KOLE MODIFICATION OF SUB-APICAL
OSTEOTOMY
Indications:
Mandibular prognathism with ant. open
bite.
Severe reverse curve.
Excessive chin height.
Functional post. occlusion.
Satisfactory lip-tooth relationship & no
transverse deficiency in maxilla.
The principle disadvantage here relates
unpredictable soft tissue profile changes & chin
height changes.

Sagittal Split Ramus Osteotomy
•

•

•

•

This surgery can be performed in both extraction &
non-extraction cases.
It is indicated in open-bite cases with severe mand.
deficiency or prognathism.
It is usually done along with maxillary osteotomy to
minimize relapse.
If performed separately, posterior overcorrection with
an interocclusal splint, supra-hyoid myotomy and
cervical collar should be considered to prevent
relapse

Le Fort-I Maxillary Osteotomy
•
•
•
•

This surgery is indicated in open-bite cases with:
High & constricted palatal vault.
Lip incompetence.
High mand. plane angle.
Increased distance between the palatal root apices &
the nasal floor.


•

•

•

If the inferior turbinates are interfering with the
repositioning of the maxilla, they are trimed with a
Mayo scissors (Adjunctive Inferior Turbinectomy ).
Stabilization of the maxilla is done with trans-osseous
26-guage wire sutures.
If there are bony defects after surgery, bone grafts
from the Iliac crest or Hyroxyapatite crystals are used
to bridge them.


GENIOPLASTY

1.
2.
3.
4.
5.

Fridrich et al. in 1997 described various
Genioplasty stratergies for anterior facial vertical
dysplasias.
Different types of Genioplasty:
Sliding advancement genioplasty
Genioplasty with parallel ostectomy
Genioplasty with down graft
Genioplasty with anteriorly tapered ostectomy
Sliding setback genioplasty

RETENTION & RELAPSE
•
•

•
•

The main etiological factors responsible for relapse
after orthodontic correction are:
Latent vertical growth of the face.
The role of the tongue.
The main etiological factors responsible for relapse
after surgical correction are:
Mandibular musculature
Incompletely understood biomechanical factors
influencing the Elevator group & Suprahyoid group
of muscles.

The success of treatment depends upon the ratio:
Magnitude of improvement
Success = Magnitude of relapse
Wick Alexander stated that retention begins with
Diagnosis & Treatment planning.
‘Begin with the end in mind’ should be the
philosophy of treatment.

RETENTION AFTER ORTHODONTIC
CORRECTION :
Criteria to begin retention are :
1.
Coincidence of Centric relation & occlusion.
2.
Class I cuspid relation.
3.
Maintenance of mand. cuspid width.
4.
Interincisal angle close to normal.
5.
Normal ant. Overbite & Overjet.
6.
Normal Buccal Overjet.


7.
8.
9.
10.

Levelled max. & mand. arches.
All spaces closed & all rotations eliminated.
Roots parallel near extraction sites.
Posterior cusps may or may not be settled.


1.

2.
3.

Active retention normally utilizes :
A maxillary wraparound retainer and a mandibular
3x3 bonded retainer.
A full coverage clear acrylic appliance.
In conjunction with myofunctional therapy, tongue
position exercises are advocated.


•

•

•

John Sheridan in 1997, described the Force
Amplified System for corrected open-bite.
It involves
a) The use of conventional max. & mand. cuspid
to cuspid bonded lingual retainers,
b) Low-profile bonded lingual Caplin hooks and
c) Intraoral elastics.
The retainers are bond to each tooth to distribute the
elastic forces.


RETENTION AFTER SURGICAL
CORRECTION :
1.
2.
3.

4.

Upper & lower border wiring of the mandible.
Steinmann pins to stabilize the maxilla.
Skeletal wire fixation (Circumzygomatic &
Circummandibular wires).
Rigid fixation.


conclusion
The treatment of open bite still remains a challenge to
the clinician, and careful diagnosis and timely
intervention will improve the success of treating this
malocclusion.


Thank you
For more details please visit


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