Headgear /certified fixed orthodontic courses by Indian dental academy

HEAD GEARS
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

In order to conduct orthodontic treatment, force and the
various modes in which force can be applied for
treatment effects is of great significance. Most of forces
can be generated from intra oral sources, when the
intraoral sources are found to be insufficient, extraoral
forces are resorted to.
Among the most commonly used extraoral force
generating source are the headgears.
Headgears are available in a wide variety of
configurations and are programmed to deliver forces in
predetermined directions to bring about orthodontic and
orthopaedic movements.

The first reported use of headgear anchorage for
correction of protrusion of the upper anterior
teeth was made by kingsley in 1866. Upper first
bicuspid teeth were extracted , a gold frame was
made to fit around the upper anterior teeth and
this was attached with elastic ligatures to a
leather headcap.
Edward H.Angle reported on his occipital
anchorage appliance in 1888. It consisted of
clamp bands with tubes on upper first molar
teeth, a labial bow that attached with with a ball
& socket arrangement to an archwire (“B”
arch) , and a headcap that attached to the
facebow with elastic traction bands.

The labial bow contacted the anterior teeth
and these teeth were tipped lingually by
action of headgear.
Calvin case patented his headgear in
1907, not only could he retract anterior
teeth , but he could also torque and
intrude them. Case was also able to
retract teeth in buccal segments to correct
class II malocclusions.

Setback – 1) Angle said that even though
occipital anchorage is efficient, best
approach is intermaxillary anchorage.
2) Case said about disadvantage of
discomfort & irritation with occipital force.
With these pronouncements headgear use
in United States came to an abrupt stop.

Headgear use continued in europe.
Dr. Albin Oppenheim used headgears to
uncrowd teeth & to correct class II
malocclusions, without having to extract teeth &
without creating double protrusions.
In U.S. Kloehn influenced by Oppenheim’s work
started using headgears to correct Class II
malocclusions.


His greatest innovation was to solder outer
bow to inner bow , thus by raising or
lowering arms of outer bow, he controlled
adverse distal tipping of molars.
He introduced elastic neck strap to apply
traction – Cervical headgear/Kloehn
headgear.


Later some orthodontists used occipital/
high pull headgear – a) to prevent
mandibular rotation.
b) Attached to upper incisors to keep them
intruded & torqued while retracting them.
But Ricketts stopped using high pull
headgear in 1950s claiming they were
very slow in class II correction and they
also did not prevent dolichofacial patterns
of facial growth.

Ricketts observations with cervical headgear
were – 1) There was retraction of maxillary
complex as measured at point A.
2) Palate rotated in a clockwise direction.
3) There was minimal extrusion of upper 1st
molars & incisor teeth.
4) Occlusal plane rotated in anticlockwise
direction.
5) Minimal or no adverse rotation of mandible.


Graber in 1955 article ‘Extra oral force –
Facts & fallacies quote –
1) There is no evidence that maxillary
growth , per se is affected.
2) Bodily distal movement of molars can be
accomplished, but in most cases it is
merely restrained from coming forward in
its normal path or tipped distally.
3) It is possible to impact 2nd molars
temporarily by excessive distal tipping of
first molars.

4) Class II Div I malocclusions are
amenable to correction by use of extraoral
force. Marked improvement in basal
relations can be obtained.
5) Growth is an important factor, its
presence or absence profoundly
influences the results. Coordination of
treatment with pubertal growth spurt
means a greater likelihood of success.

CLASSIFICATION
There are various types of headgears
depending on the location of the anchor
unit. These are listed as follows:
Cervical Pull
High Pull
J-hook
Asymmetric/Unilateral.

Appliance Design
Basic Elements:
1 Force delivering unit i.e. face bow, 'J'
hooks.
2 Force generating unit i.e. Elastics,
springs.
3 Anchor Unit i.e. Head cap, Neck pad

Face Bows : Made of stainless steel having a
diameter between 0.040" to 0.051". It
engages buccal tubes on the first molars.
The methods used to make the inner bow
stop mesial to the 1st molar are:
Bayonet Bends / Horizontal inset bends which
prevent the anterior portion from impinging on
brackets on teeth.
Stops : Cylindrical tubes with an internal
diameter corresponding to inner bow diameter.

Preformed inner loops: serve as adjustable stops
as well as shock absorbers and are angulated
for clearance.
They also facilitate necessary unilateral
adjustments to keep the facebow comfortably
centered, increase facebow length as molars
gradually move distally & reduce facebow length
as incisors are retracted.
Trevor Johnson friction stops: with internal
diameter of 0.045" which can be soldered to
inner bow to serve as stops.


Outer Bow (Wisker Bow)
Acts as a media through which force is
transmitted to the inner arch. Dentaurum
products have a standard bilaterally symmetrical
facebow in which the joint between the inner and
outer bow can come with or without cuspid
hooks and in 3 sizes short , medium and long.
Outer bow dimension – 0.051" – 0.062" stainless
steel contoured to the check contour with the
inner and outer bow joint lying between the lips
when the inner bow engages the buccal tube.

–

Miscellaneous Components:
Springs : Calibrated tension springs are
available. These have the advantage that the
applied force can be varied.
Elastics : Serve as force elements and are
available in the following forms:
Neck bands with strong/medium pull
Extraoral plastic chins with length 119 mm
Ribbon Headgears for making individual HG's.

Safety pads : for elastic bands
Neck pads with length 180 mm
Flexi pads in roll form for individual size.


Friction Release Systems : These include safety
release to reduce "sling-shot' hazards by means of
clips which release automatically when pulled with
excessive force. They provide case of assembly
and include an inner steel coil to provide a
consistent traction force.
Prescription Tab variable Force Neckpads : These
provide adjustable calibrated force of 8-18 oz .
Headcaps : of the following types are available:
Pressembled Standard universal
Preassembled Extra Comfort
Vertical Pull


Cervical Pull Headgear
Dr. Silas J. Kloehn first described it on 1947. It
is also known as the Kloehn Headgear.
This was to become the most widely used form
of an extraoral traction appliance to be used in
contemporary orthodontics.
Dr. Kloehn reported the use of a headgear
attached by means of hooks to an upper 0.045"
archwire stopped against the upper permanent
first molars giving a reasonably well controlled
force action with a cervical neck strap to general
force.

Since the anchor unit (neck strap) passes
around the patients neck and is attached
to the outer bow to produce a force acting
5˚-10˚ tangent the occlusal plane, it is
called the cervical pull headgear.
Recommended time of wear is 12-14
hrs/day This disto occlusally directed force
has an extrusive effect on the molars.


The effects of the appliance itself are most
clearly revealed in instances where the
Headgear is worn for 14 hrs/day especially when
the patient is experiencing a relatively small
amount of growth.
As the distoocclusally directed force has an
extrusive effect on the molars the cervical-Pull
Headgear is not recommended in cases having
an elevated mandibular plane angle or open bite
cases.


High-pull headgear
The high-pull facebow is attached to the
maxillary first molars by way of an inner bow that
is the same length as the outer bow.
The outer bow is bent upward so that the point
of force application and the direction of force lie
above the center of resistance of the maxillary
first molars. The inner bow lies passively in the
molar tubes, or it can be expanded if an
increase in transpalatal width is desired

Rationale justifying the use of a High-Pull
Headgear –
Cervical-Pull headgear's have certain drawbacks
that are especially undesirable in a majority of
Class II Division I cases.
These problems have their origin in the line of
action of the force, generated by a cervical-pull
extraoral traction device, which often passes
below the centre of resistance of the maxillary
first molar.


As a result of this, it produces a moment of
force which results, in the mesial tipping of
the roots and a distal crown inclination of
the posterior maxillary buccal segment.
An additional drawback of the cervical pull
headgear is the distooclusally orientation
of generated force which causes
extrusionof molars. This prevents it's use
in patents having a high mandibular plane
angle.

The tendency of the cervical-pull headgear
to cause the tipping and extrusion of
molars might compromise the stability of
the orthodontically corrected dentition.
So concept and utility of the High-pull
headgear was put forth where the
resultant force was directed through the
level of trifuriation of maxillary molars in a
postero-superior direction.

With the High-Pull Headgear, it is possible
to change the direction of force in relation
to the center of resistance of the dental
units to which the force is being applied in
order to achieve better control of resulting
tooth movement in a distal direction,
and to modify vertical changes in the
maxillary molar position to correct Class II
relationships using a relatively lower
magnitude of forces.

Treatment effects of the High-Pull
Headgear include intrusion and
distalization of maxillary models,
Anti-clockwise mandibular rotation,
decreased lower facial height,
retrusion of incisors etc.


Root High-Pull Facebow
This facebow is designed to produce in
intrusive force on the upper buccal
segment which makes it valuable in the
treatment of open-bite malocclusions.
Parts:
High-Pull heads strap with traction release
force modules.
Facebow with outer bow tips terminating in
approximation of 1st molar region.

Root proposed that if the posterior vertical
dimensions are controlled, more of the
mandibular growth, will be, expressed in the
horizontal direction thereby conserving or
'maximizing' the horizontal growth of the
mandible.
In addition, when 'J' hooks are attached to
hooks between upper central and internal
incisors, it is impossible to dislodge them during
normal usage from the soldered hooks.

The purpose of the high pull Headgear when
used in this manner is to produce a retrusive
and intrusive force on upper anteriors. This
force is also useful in counteracting the
downward vector of force produce by Class II
elastics.
In patients with low mandibular plane angles that
need as much vertical development as possible,
the combination of a high-pull Headgear with
class II elastics can aid in predictable horizontal
and vertical correction of malocclusions with the
lower lip providing adequate restraint to class II
elastic pull.

The Interlandi type High-Pull Headgear
In this design, the outer bows are attached
to the head straps of the headgear with
the help of ½" later elastics. The direction
of the applied force was modified by
changing the point of attachment of the
elastics. The level of buccal trifurcation of
the maxillary first molar is to be clinically
and radiographically determined.


In order to prevent the distal tipping of molars,
the end of the outer bow must terminate in the
same plane as the centre of the upper 1st molar.
Therefore, the force component is aligned to
pass through the approximate centre of
resistance of these teeth.
The inner bow is made parallel to the occlusal
plane and the length of the outer bow is reduced
so that it does not extend distal to the maxillary
first molar. A force of 500 gms/side is used with
recommended wear of 12 hrs/day.

Combination Facebow
The cervical facebow and the high-pull
facebow can be used in combination
(hence the term "combi facebow") to alter
the direction of force along the plane of
the occlusion.
Advocated by Armstrong (1971) and
Berman (1976).


J-Hook Headgear
The forces produced by extraoral traction also
can be attached anteriorly by means of J-hooks
to the archwire or to hooks soldered to the
archwire.
Flared maxillary incisors can be retracted using
either a high-pull or a straight-pull headgear
combined with J-hooks that are attached to the
archwire anteriorly or by using a closing arch
supported by headgear.

Headgears with J-hooks also are used to
potentiate archwire mechanics by helping control
forces incorporated into the archwire (e.g.,
torque, intrusion).
J hooks can be applied to the maxillary teeth in a
variety of force vectors to retract and intrude the
maxillary incisor teeth.
Usually done in edgewise mechanotherapy.


A similar type of retraction-stabilization of
the mandibular dental arch also can be
achieved. In addition, it is possible to
attach J-hooks to the maxillary arch and
the mandibular arch simultaneously.
Armstrong (1971) , Hickham (1974) and
Vaden et al (1986) have used 4 J hooks
with the interlandii headgear to
simultaneously retract maxillary &
mandibular canines.

Hickham (1974) also suggested use of
diagonally set J hooks for reciprocal correction
of maxillary & mandibular centre lines.
In Tweed-Merrifield non extraction treatment, Jhook headgear is also attached to mandibular
anterior teeth to prevent mandibular incisor
proclination during the resolution of lower incisor
crowding and the preparation of mandibular
anchorage.


Asher Face Bow : Demonstrated by Roth.
This is a High-Pull facebow with a headcap
and short intra-oral bow.
Used to retract maxillary incisors in premolar
extraction spaces using 12-15 ounces of force.
It applies force directly to maxillary canine
brackets.

Advantages:
– Comfortable to wear.
– Conserves anchorage
– Simultaneous retraction of both arches. Helps
in intrusion of incisors.


Distalizing plate of Margolis & Cetlin
Commonly called ACCO appliance.
AC – Acrylic
CO – Cervical Occipital Anchorage.
A removable plate is used to distalize
maxillary molars bodily. During 2nd phase
during which space consolidation occurs,
extraoral forces help maintain anchorage
posteriorly.

Headgear with Activator:
– Reported by Stockli + Teuscher (1964)
wherein a cervical HG was attached to upper
molars.
– Pfeiffer attached the HG directly to the
activator and applied occipital traction to
achieve better vertical and rotational control
during Class II treatment.
– Bass modified the appliance and used a 'J'
hook headgear.

– Primary treatment objective is to restrict
developmental contributions that tend to
cause a skeletal Class II and at the same time
attempt to correct anteroposterior relation of
jaws.
– Usage mainly limited to mixed dentition with
force application of 250 gms/side.


Headgear with Herbst Appliance:
– First described by Wieslander (1984) wherein
the headgear is fixed to a tube soldered to the
molar attachment.
– High-pull force direction using 1000 gms/side
of force and worn for 12-18 hrs/day in mixed
dentition period.
– Produces a synergistic effect on correction of
skeletal Class II cases wherein the Herbst
Appliance stimulates mandibular growth while
this headgear force redirects maxillary growth.

Graber Appliance:
– Plastic positioner type appliance made to fit
the teeth with incorporated metal arms which
receive the extraoral source of force.
– Used in treatment of Class II Division 1 cases
by allowing arch expansion.
Mills Vig appliance:
Consists of an active expansion plate with
a jack-screw to eliminate maxillary
narrowing and crossbite.
Soldered buccal tubes to molars receive
face-bow end.

Asymmetric/Unilateral headgears

Orthodontic treatment often requires an
extraoral force that will predictably deliver
a greater distal force to one side of dental
arch than to the other. (e.g., Class II molar
relationship on one side, Class I on the
other
The inner bow is shortened on the Class I
side, and the outer bow is bent away from
the cheek.

The center of attachment to the inner bow
is moved laterally, thus producing
asymmetrical forces against the two sides
of the dental arches.
Disadvantage - Extended use of this
device will tend to skew the arch to one
side.


4 types –
1) Power arm face bow – One outer bow is
longer/wider than the other. Longer/Wider
bow tip is located on side anticipated to
receive greater distal force.
Power arm face bow also generates lateral
forces which tend to move the favoured
molar tooth into lingual crossbite and the
opposite molar into buccal cross bite.

2) Soldered offset face bow - outer bow
is attached to inner bow by means of a
fixed soldered joint placed on the side
favored to receive greater distal force.
3) Swivel offset face bow – In this design,
outer bow is attached to inner bow by
means of a swivel joint located in an offset
position on the side favored to receive
greater distal force.
Said to minimize undesirable lateral forces.

4) Spring attachment face bow – An open
coil spring is wrapped around one of the
inner bow terminal of a conventional
bilaterally symmetrical face bow.
Coil is placed distal to the slope on side
favored to receive the greater distal force.


Biomechnaical aspects.
Location of centre of resistance
a) Maxillary first molar – Situated at trifurcation of
the roots.
Worms et al(1973) reported that distalization of
maxillary first molars led to occlusal & distal
movement of erupting 2nd molars . Due to
resistance offered by erupting 2nd molars, centre
of resistance of 1st molars move from root
trifurcation towards crown.

2) Maxillary dental arch – Between the roots of
1st & 2nd premolars.
3) Maxilla/Nasomaxillary complex – Nanda &
Goldin(1980) reported it to be in central part of
zygoma.
According to Billet et al (2001) it is same as
maxillary arch.
Tanne et al (1995) – At pterygo-maxillary fissure.
4) For 4 maxillary incisors – According to Melsen
et al(1990) it is within roots of central & lateral
incisors.

Pedersen et al (1991) & Vanden et al
(1986) reported it to be more distally.
5) Maxillary six anterior teeth – Melsen et
al(1990) estimated it to be in centroid of
triangle linking centers of resistance of
central, lateral incisors & canines.
Vanden et al (1986) reported it to be distal
to 2nd premolar root.
Pedersen et al (1991) – Between canine &
1st premolar roots.

Cervical pull headgear
The decision to treat with cervical headgear
needs to be based on a complete understanding
of the desired tooth movement and the force
system that is produced with this headgear style.
Line of force moment (LFO), is a line from the
strap-force application point through the
maxillary center of resistance.
The different moments and forces produced by
the cervical headgear depend on the situation of
the outer bow in relation to the LFO.

When the outer bow lies
along the LFO, no
moment occurs, and the
force system will be
reduced to a bodily
movement in a posterior
and extrusive direction.
Outer bow is equal length
to inner bow.
If the outer bow is placed
above this line, it passes
distal to centre of
resistance the moment
produced by the force will
be in a counterclockwise
direction. Outer bow is
long.

If the outer bow is adjusted below this line the
moment created will be clockwise. However, the
direction of the forces are the same - extrusive
and posterior. Tends to steepen occlusal plane.
In such cases outer bow is short length.
If the outer bow is located below the neckstrap,
the resultant force will be a small intrusive one,
instead of extrusive. Of course, a distal force
and large clockwise moment will also be
produced.


The direction of pull provided by the cervical
headgear is especially advantageous in treating
short-face Class II maxillary protrusive cases
with low mandibular plane angles and deep
bites, where it is desirable to extrude the upper
posterior teeth.
Also, the clockwise moment that is so readily
produced with this headgear is very effective in
helping conserve anchorage in extraction cases.

High Pull headgear
This style headgear always produces an
intrusive and posterior direction of pull,
due to the position of the headcap.
The direction of the moment that is
produced is dependent on the position of
the outer bow .


If the outer bow is placed anterior to the
LFO, either above or below the occlusal
plane level, the moment produced will be
counterclockwise.
On the other hand, if the outer bow is
placed posterior to this line, the moment
produced will be in a clockwise direction.
The magnitude of this moment will be
proportional to the distance of the outer
bow to the CR.

If a distal and intrusive movement with no
moment is desired, the outer bow must be
placed somewhere along the LFO.
This force system would be beneficial in a
long-face Class II patient with a high
mandibular plane angle, where intrusion of
maxillary molars would decrease facial
height and improve the facial profile.

Straight Pull headgear
This style headgear is a combination of the high-pull and
cervical headgear, with the advantage of increased
versatility. Depending on the force system desired, the
orthodontist has the opportunity to change the location of
the LFO.
The prime advantage of this headgear is its ability to
produce an essentially pure posterior translatory force.
This is accomplished by placing the LFO through the
center of resistance, parallel to the occlusal plane.
Clinically, this means bending the outer bow to the same
level as CR, and hooking the elastic to a notch at the
same vertical level.

The relation of the outer bow to the LFO
dictates the direction and magnitude of
forces and moments.
Placing the outer bow above the LFO will
produce a posterior force,
counterclockwise rotation, and most often
an intrusive force.


If the outer bow is below the LFO, the force
produced will be posterior and superior, and the
moment will be in a clockwise direction.

The straight-pull is the headgear of choice in a
Class II malocclusion with no vertical problems.
It is also the headgear of preference when the
main thrust of headgear wear is to prevent
anterior migration of maxillary teeth, or possibly
even translate them posteriorly.

Vertical pull headgear
The main purpose of this headgear is to produce
an intrusive direction of force to maxillary teeth,
with posteriorly directed forces. If the outer bow
is hooked to the headcap so that the line of force
is perpendicular to the occlusal plane and
through the CR, pure intrusion may take place.
The vertical-pull headgear is not as commonly
used as are the others. However, it is very useful
when pure intrusion of buccal segments is
required, as in the Class I open-bite patient.

Asymmetric headgear
The critical consideration is the geometric
configuration of the outer-bow tips relative to the
midsagittal plane of the inner bow.
Evaluation of the mechanics is developed
around the basic concept that only when the
outer-bow tips of an activated face-bow are
asymmetrical about the midsagittal plane of the
inner bow can unilateral forces be delivered to
the inner-bow terminals.
Given equal tractional forces, if no asymmetry
of activated outer-bow tips is present, no
unilateral distal forces can be delivered to the
inner-bow terminals.

The face-bows are oriented so that the X axis
passes through a point on the terminal ends of
the inner bow and perpendicular to the
midsagittal plane (Y axis).
The tractional forces FL and FR, which are equal
in magnitude, are directed posteriorly and
medially from the outer-bow tips and converge
to form a tangent with the curvature of the neck.
In all true unilateral face-bows, extension of
these tractional forces allows then to intersect at
a point to the right of the midsagittal plane.

Bisection of the angle formed by the two
tractional forces FL and FR yields a resultant
force FZ. When resultant force FZ is extended, it
intersects the interterminal line (X axis) to the
left of the midsagittal plane (Y axis) and divides
the interterminal line into unequal lengths a and
b.
Because the resultant force intersects the
interterminal line to the left of the midsagittal
plane, the left inner-bow terminal (RLY) receives
a greater distal force than the right inner bow
terminal (RRY) Given those conditions, the
distribution of these distal forces can be
determined.

Distal force exist on both sides but they
are 3 times greater on long outer bow than
short outer bow.
Also one has to watch if any crossbite is
developing because of lateral forces


In an evaluation of the lateral forces, a
distinction must be made between the net lateral
force and the lateral forces delivered to each of
the two inner-bow terminals.
The net lateral force is the sum of force applied
to both inner-bow terminals.
The direction of this net lateral force will always
run from the inner-bow terminal receiving the
greater distal force toward the side receiving the
lesser distal force.

The magnitude of this net lateral force is
theoretically determinable. In contrast, the
distribution of the lateral forces delivered to each
of the specific inner-bow terminals is
indeterminant and cannot be resolved
theoretically.
One can only say that, at a given time, a specific
inner-bow terminal is receiving a portion of the
net lateral force that ranges in magnitude from
all of the net lateral force to none of it.

J hook headgear
This type of pull places an intrusive &
distal force upon upper incisors.
In theory high pull should be placed so
that line of force passes labially to center
of resistance, this will tip root palatally &
crown labially.
In practice difficult to achieve unless
incisors are proclined or pull nearly
vertical.

Hooks pointing occlusally & soldered distal to
upper central rather than upper lateral makes
vertical support more effective.
Line of force passing – a) Mesial & apical to
center of resistance : intrude & distalize upper
incisors & augment palatal root torque.
b) Passing through the center of resistance will
have a large distal & small intrusive effect.
c) Passing occlusal – has a mild downward
tipping effect upon incisal end of occlusal plane.

Low pull J hook neckgear
Can cause tipping of incisal end of occlusal
plane in a downward direction,resulting in
reduction of open bite.
If used in mandibular incisor region, it may
depress chin creating more vertical space into
which maxillary teeth can be extruded during
class III treatment.
Resultant downward & backward mandibular
rotation reduces the A-P basal discrepancy.

TREATMENT EFFECTS
Extraoral traction has been shown to
produce a variety of skeletal and
dentoalveolar effects in Class II patients.
Even though there is some agreement
among investigators as to the effects
produced, the clinical management of the
appliance, the direction of force applied
and the amount of force used may explain
some of the differences among
investigation.

Anteroposterior Dimension
Maxillary Skeletal Position
A primary treatment effect of extraoral traction is
the restriction of maxillary skeletal growth. There
is virtually universal agreement that because of
treatment Point A is repositioned posteriorly
relative to the remainder of the face, resulting in
a reduction in maxillary prognathism.
Wieslander (1974) has shown that this technique
also influences that cranial base by producing a
counterclockwise tilting of the spheno-ethmoid
plane during 3-4 years of treatment with a
headgear.

Maxillary Dentoalveolar Position
Distal movement of the maxillary molars is a
typical treatment effect produced by cervical
headgear therapy. In contrast, Hubbard and coworkers(1994), who studied a sample of patients
treated by Kloehn, reported a mesial movement
of the first molar.
Extrusion of the maxillary molars also has been
observed, with two to three times as much
extrusion reported as would be expected during
normal growth. On the other hand, Hubbard and
colleagues did not observe molar extrusion.

Mandibular Dentoalveolar Position
There is virtually no literature that
addresses the effect of the cervical-pull
facebow on the mandibular dentition other
than the treatment effects that are
produced in association with fixed
appliance treatment. There appears to be
no effect.


Mandibular Skeletal Position
The anteroposterior relationship of the chin has
been correlated to the amount of vertical
opening produced during treatment. A downward
and backward rotation of the mandible and a
similar movement of Point B and pogonion have
been reported, as has an opening of the
mandibular plane angle.
Kloehn(1947) and Ringenberg and Butts(1970)
report no change in the SNB angle, but other
investigators ( Mcnamara, 1996, Graber 1956)
note either a posterior or anterior movement of
Point B.

Vertical Dimension
There is no universal agreement as to the
effect of cervical headgear treatment on
the vertical dimension, as investigators
have differed in describing the effect of
this type of therapy on the various aspects
of vertical facial measures.


Mandibular Plane Angle and Lower Anterior
Facial Height
An increase in the mandibular plane angle as
the mandible is hinged open has been reported
by many investigators.
An opening of the bite and an increase in lower
anterior facial height also has been a frequent
finding. Klein(1956) report that extraoral force
tends to open the Y axis angle and lengthen the
face more than would occur with normal growth.


A high-pull headgear has been
recommended to reduce the extrusion of
the maxillary first molars.
In contrast, Ringenberg and Butts(1970),
Baumrind(1978) , and Hubbard and coworkers(1994) report a closure of the
mandibular plane angle with treatment,
whereas others reported no change.

Occlusal Plane Angle
Investigators have differed as to the effect of
extraoral traction on the orientation of the
occlusal plane relative to the cranial base.
The anatomic occlusal plane normally closes
with age. Klein(1957), King(1957), and Hubbard
and colleagues (1994) reported that the angle of
the occlusal plane remain unchanged relative to
the cranial base.
Hubbard and associates noted that the
functional occlusal plane closed slightly with
treatment as well.

Palatal Plane Angle
The palatal plane has been shown to tip
anteriorly with an uneven descent,
resulting in the anterior nasal spine tipping
more inferiorly than the posterior nasal
spine.
On the other hand, Kloehn(1961) and
Boecler and co-workers(1989) noted no
change in the palatal plane.

Transverse Dimension
In the literature , changes in the transverse
dimension with extraoral traction has been
minimal.
Ghafari and co-workers(1994), who conducted a
comparative study of the straight-pull headgear
and FR-2 appliance of Frankel.
The inner bow of the facebow was adjusted at
every appointment "to avoid any constriction or
major expansion of the intermolar distance,"
resulting in a total expansion of the inner bow of
1.5-2.0 mm.

Ghafari and colleagues noted increases not only
in intermolar distance, but in intercanine
distance as well.
These investigators hypothesized that the
change in intercanine distance, a region not
directly affected by the facebow, may have been
a result of a shielding effect by the inner bow on
the lip and cheek musculature, an indication of
the influence of the buccal and labial
musculature on tooth position.


Stienberger , Burstone, Andersen (Angle
2004) did a study to see whether high pull
headgear can prevent steepening
/extrusion of buccal segments during
incisor retrusion and whether it can
increase the rate of incisor intrusion.
Results showed that high pull headgear
has no effect on extrusion of buccal
segments during incisor retrusion nor any
effect on rate of intrusion.

Haulabakis et al (AJO 2004) studied the
effect of cervical headgear on patient with
high or low mandibular plane angle, and
assessed the ‘myth’ of posterior
mandibular rotation.
They concluded that regardless of
treatment taken, vertical skeletal
relationship was not affected.

Leandro et al ( AJO 2005) studied the
effects of cervical headgear on space
available for maxillary 2nd molar to erupt.
They suggested that despite restriction of
movement of maxillary 1st molar & maxilla,
there was sufficient space for 2 nd molar to
erupt because of posterior displacement
of PTM point & growth at maxillary
tuberosity.

Serdar Usumez, Metin Orhan ( EJO 2005)
studied effects of cervical headgear on
head position.
They found that it causes a significant
cranial flexion, which may be responsible
for its effects on mandible that is it can be
a initiating factor for forward mandibular
positioning.


Hubbard et al ( Angle 1994) studied the effects
of orthodontic treatment with the use of cervical
headgear in class II malocclusion patients .
Overall the results showed changes were very
close to what would occur as a result of normal
growth in class I individuals.
Maxillary 1st molars continue to grow forward,
cranial base showed very little change.
Mandibular plane angle did not increased
appreciably with treatment


Distal molar movement with Kloehn headgear:Is it
stable?
Birte Melsen, and Michel Dalstra, (AJO 2003)
The aim of this study was to evaluate intramaxillary
molar movement after 8 months of cervical traction and
posttreatment displacement 7 years later.
The total molar displacements in relation to stable
intraosseous reference points were compared with those
observed in an untreated control group that also had
intraosseous reference indicators inserted.
During the headgear period, the type of molar
displacement could be predicted by the direction of the
force system acting on the teeth.


It was noted, however, that the variation in the
vertical development was related more to each
patient’s growth pattern than to the force system
applied. After cessation of the headgear,
intramaxillary displacement of the molars was
noted, and the total displacement of the molars
did not differ from that of the untreated group.
The indication for intramaxillary displacement of
the molars by means of extraoral traction is
therefore questioned.


Birte Melsen ( AJO 1978) have reported
that influence of headgear on growth
pattern of facial skeleton was reversible.


Quantitative analysis of the orthodontic and
orthopedic effects of maxillary traction
Sheldon Baumrind, ,Robert J. Isaacson ( AJO
1983)
They analyzed differences in displacement of
ANS and of the upper first molar when different
vectors of force are delivered to the maxilla in
non-full-banded Phase I mixed-dentition
treatment of Class II malocclusion.
Study included a cervical-traction group, a
high-pull-to-upper-molar group, a modifiedactivator group, and an untreated Class II
control group.

Orthopedic distal displacement of ANS was
significantly greater in the high-pull and cervical
groups than in the activator group. Orthopedic
downward displacement of ANS was seen to be
significantly greater in the cervical group than in
the high-pull and activator groups.
In the region of the first molar cusp, mean distal
displacement of the tooth as an orthopedic effect
was found to be almost identical in the cervical
and high-pull groups (although variability was
greater in the cervical group), but the mean
orthodontic effect was significantly greater in the
high-pull group than in the cervical group.


The cervical-traction group showed
significant mean extrusive effects of both
the orthodontic and the orthopedic types,
but even for this group total extrusion was
on average no more than 1 mm. as
compared to the control group.


Changes in mandibular position and upper airway
dimension by wearing cervical headgearduring sleep
Hiyama et al ( AJO 2001)
The purpose of this study was to examine changes in
mandibular position and oropharyngeal structures that
were induced by the wearing of cervical headgear during
sleep. Ten healthy adults (7 male and 3 female) who
gave their informed consent were included in this study.
A pair of lateral cephalograms was taken with the patient
in the supine position with and without cervical headgear
at end-expiraton stage during 1 to 2 non rapid eye
movement sleep.


Amount of jaw opening was significantly
decreased by the wearing of the cervical
headgear (P < .05), although no significant
anteroposterior mandibular displacement
was induced.
The sagittal dimension of the upper airway
was significantly reduced (P < .05);
however, no significant changes were
observed in the vertical length of the upper
airway.


Although the hyoid bone and the third cervical
vertebra moved significantly forward by the
wearing of the cervical headgear (P < .05), the
relationship among the mandibular symphysis,
the hyoid bone,and the third cervical vertebra
did not change.

These results suggest that cervical headgear
significantly reduced the sagittal dimension of
the upper airway during sleep, although there
was no significant anteroposterior displacement
of the mandible.

Force duration & magnitude
Standard extra oral force fell in range between
400 & 700gm.
700 gm for 12 – 14 hrs is required for an
orthopaedic effect.
Ricketts (1979). – force of 150gm was
appropriate for extra oral retraction in adults and
children. 500gm was required for orthopaedic
change.
Kloehn considered that between 350 & 700gm of
force was the most that could be tolerated.


Armstrong(1971) used more than 2000gm.
McLaughlin, Bennett & Trevisi (2001)
recommended a force level of 250 to 350gm to
provide anchorage for fixed appliances.
In combination system - 100gm cervical pull
with 150gm high pull for anchorage.
For extra oral traction ; 150gm cervical pull with
250gm high pull headgear.


Duration of force : 10 – 12 hrs for
anchorage.
12 – 14 hrs for traction for distalization of
molars or for orthopaedic effect.


Valiathan et al (JIOS1994) reported case
of class II div I malocclusion treated non
extraction with help of headgear.
Patient had come with a complaint of
prominent upper teeth.
Extra oral examination – Convex profile,
incompetent lips.
Intra oral examination – Class II
molar/canine relation, missing lower left
central incisor. Overjet was 11mm,
Overbite - 5mm.

Patient was motivated to wear headgear.
Duration of headgear wear – 10 – 12 hrs/day.
10 – 12 ounces force on each side.
At end of treatment ANB reduced from 6˚ to
3 ˚. IMPA – 100˚ to 89˚.
Molar relation became class I, lips became
competent & Profile improved considerably.
Total treatment duration was 2 yrs 2 months.


Comparison with Functional
appliances


Outcomes in a 2-phase randomized clinical trial of early Class II
treatment.
Tulloch JF, Proffit WR, Phillips C. (Am J Orthod Dentofacial Orthop.
2004)

In a 2-phased, parallel, randomized trial of early
(preadolescent) versus later (adolescent) treatment for
children with severe (>7 mm overjet) Class II
malocclusions.
Favorable growth changes were observed in about 75%
of those receiving early treatment with either a headgear
or a functional appliance. After a second phase of fixed
appliance treatment for both the previously treated
children and the untreated controls, however, early
treatment had little effect on the subsequent treatment
outcomes

Anteroposterior skeletal and dental changes after early
Class II treatment with bionators and headgear
Stephen D. Keeling (Am J Orthod Dentofacial Orthop1998)

In this study authors examined anteroposterior
cephalometric changes in children enrolled in a
randomized controlled trial of early treatment for Class II
malocclusion. Children, aged 9.6± 6 0.8 years at the
start of study, were randomly assigned to control (n=
581), bionator (n= 578), and headgear/biteplane (n
=590) treatments.
Cephalograms were obtained initially, after Class I
molars were obtained or 2 years had elapsed, after an
additional 6 months during which treated subjects were
randomized to retention or no retention and after a final 6
months without appliances.

Both bionator and head-gear treatments
corrected Class II molar relationships, reduced
overjet and apical base discrepancies, and
caused posterior maxillary tooth movement.
The skeletal changes, largely attributable to
enhanced mandibular growth in both headgear
and bionator subjects, were stable a year after
the end of treatment, but dental movements
relapsed


Headgear versus function regulator in the early
treatment of Class II, Division 1 malocclusion: A
randomized clinical trial
J. Ghafari,F. S. Shofer, U. Jacobsson Hunt, D.
L. Markowitz, and L. L. Lasterb
A prospective randomized clinical trial was
conducted to evaluate the early treatment of
Class II, Division 1 malocclusion in prepubertal
children. Facial and occlusal changes after
treatment with either a headgear or a Frankel
function regulator were reported.

The results indicate that both the
headgear and function regulator were
effective in correcting the malocclusion


Safety Issues
Injuries have been reported with the use of
headgear. They have been associated with the
catapult effect of simple elasticated extra oral
traction and with the face bow coming out at
night.
In some cases, facebow either was knocked,
pulled out of molar tubes while still attached to
headstrap or neckstrap. This lead facebow to
recoil and hit patient in face, head or neck.
This detachment and injuries can compromise
success of treatment.


Injuries have occurred with both
removable & fixed appliances.
Ranged in severity from minor lacerations
to loss of eye.
All occurred in children aged between 914 yrs.
The presence of oral micro-organisms on
the ends of inner bow radically alters the
outcome of the soft tissue trauma, making
the patient highly susceptible to infections.

Facebow injuries to eye can cause little
pain at the outset often delaying the child
seeking treatment
This delay allow infection to proceed
unchecked for a considerable period of
time.
Eyeball is also an excellent culture
medium, and when it becomes infected it
becomes difficult to control.

When one eye is injured there is a risk to the
other undamaged eye from a process called
sympathetic opthalmitis.
In order to prevent these injuries – several
safety devices.
These include self releasing extra oral traction
systems, plastic neckstraps, shielded facebows
and locking facebows.
Patients should be instructed on proper use of
appliance.

Facebows should be designed so that the ends
of neither the inner nor outer bow are capable of
producing either penetrating injuries or
lacerations.
Self releasing headgear/neckgear –
Manufactured in a variety of designs.
Modular systems can be use with Headcap or
neckcap.
Travel provide by these modules should enable
a comfortable range of head movement by
patient without their unintentional release

For headcap – 10mm extension.
For neckstrap – 25 mm/module.
Plastic neckstraps – Retain facebow within
buccal tubes..
As the strap is not flexible it cannot
accommodate the changing distance between
the back of neck and the facebow, and still
provide a continuous resistance to the
displacement of facebow from buccal tubes.


Shielded facebows – Shielding include on their
inner ends in an attempt to reduce the severity
or risk of soft tissue trauma.
Shielding does not improve facebow self
retentive capability and it can disengage in night.
Locking orthodontic facebows – It has 2 omega
bands so that it can easily adjusted to fit
different lengths of buccal tubes.


It successfully reduced night time
disengagement of facebow to less than
1%.
Patients instructions – 1) Never wear
headgear during playful activity.
2) If it ever comes off at night or there are
any other problems patient should stop
wearing the appliance and return to see
clinician.
3) Excessive force should not be used while
removing facebow.

4) Before removing facebow patient first
must remove headcap/neckstrap.
5) If any injury occurs to eye, eye should
be examined without delay by a suitably
trained medical practitioner.


Patient Compliance
An important aspect of using extra oral
traction is whether appliance is being worn
as instructed.
Patient’s compliance can be improved if
both parents & clinician provide
motivation.


Indicators
1) Patient keeps a daily diary of length of
use.
2) Demonstrates skill in inserting facebow.
3) Mobility of teeth receiving traction force.
4) Parentral monitoring.
5) Soiled or recently cleaned
neckstrap/headgear.

Conclusion
To obtain desired dento skeletal effect with extra
oral traction, type of appliance, amount of force,
location of centers of resistance of teeth, maxilla
& craniofacial type must be considered.
Different subjects may respond differently to
same type of extra oral traction.
Cervical, combination & occipital face bow have
similar A-P & vertical effects in growing patients.


REFERENCES
Valiathan Ashima, Gurjit Singh Randhawa & Jayan
Joseph: Class II Division I treated non extraction with
headgear, Journal of Indian Orthodontic Society, 1994;
25(1): 31-34.
Suresh M and Ashima Valiathan: Asymmetric
headgear treatment of Unilateral Class II div I
malocclusion. Kerala Dental Journal 2000; 23(1): 1518.
Ashima Valiathan and Amit Kumar Srivastava: Role of
Kloehn headgear in class II – Dental and skeletal
correction. JICD 2000;47: 9-11.

Birte Melsen,and Michel Dalstra: Distal molar
movement with Kloehn headgear:Is it stable.
AJODO 2003;123:374-8)
Leandro M. Piva, Helisio R. Leite, Maria O’
Reilly : Effects of cervical headgear & fixed
appliances on space available for maxillary 2nd
molar . AJODO 2005, 128(3);366-371.
Haulabakis NB, Sifakakis IB: The effect of
cervical headgear on patient with high or low
mandibular plane angle and the ‘myth’ of
posterior mandibular rotation. AJODO
2004,126;307 – 310.


Serdar Usumez, Metin Orhan : Effect of cervical
headgear wear on dynamic measurements of
head position. EJO 2005 (27); 437-442.
R.H.A. Samuels, N.Brezniak : Orthodontic
facebows : safety issues and current
management. J.O. 2002 (29) ; 101-107.
Keith Godfrey : Extra oral retraction mechanics :
a review. Aust. Ortho J 2004, 20; 31 – 40.


Kloehn SJ : Orthodontics – force or
persuasion. Angle Ortho 1953, 23; 56-65.
Armstrong MM : Controlling the
magnitude, duration & direction of extra
oral force. AJO, 1971, 59 ; 217-243.
Jacobson A; A key to understanding of
extra oral forces. AJO 1979,75; 361-386.

Wieslander L; Long term effects of treatment
with headgear-herbst appliance in early mixe
dentiton. AJO 1993,104; 319-329.
Hershey HG, Houghton CW, Burstone CJ;
Unilateral facebows: a theoretical & laboratory
analysis. AJO 1981; 79; 229-249.
Nanda R : Biomechanics in clinical orthodontics.
1st edtn, Philadelphia, WB Saunders,1997; 130145.

Turner PJ: Extra oral traction. Dent
Update. 1991;18;197-203.
Firouz.M, Zernik J, Nanda R; Dental &
orthopedic effects of high pull headgear in
treatment of class II div I malocclusion.
AJO, 1992;102; 197- 205.
Graber TM; Extra oral force – facts &
fallacies. AJO 1955,41; 490-505.

Birte Melsen; Effects of cervical anchorage
during and after treatment; An implant study.
AJO 1978,73,5 ; 527-539.
Gregory W. Hubbard, Ram S. Nanda, G. Frans
Currier ; A cephalometric evaluation of non
extraction treatment in class II malocclusion.
Angle Ortho 1994,64 (5); 359-370.
Charles T.Pavlick ; Cervical headgear usage &
the Bioprogressive orthodontic philosophy.
Semin. Ortho 1998, 4, 219-230.


Bowden DE; Theoretical considerations of
headgear therapy. A literature review.
Mechanical principles . BJO 1978,5;145-152.
Bowden DE; Theoretical considerations of
headgear therapy. A literature review. Clinical
response & Usage. BJO 1978,5; 173 – 181.
Contasti G, Legan HL; Biomechanical guidelines
for headgear application. JCO 1982,16; 308312.

Tulloch JF, Proffit WR, Phillips C.Outcomes in a 2-phase randomized clinical trial of
early Class II treatment. AJO 2004 Jun;125(6):657-67 .
J. Ghafari, F. S. Shofer,b U. Jacobsson-Hunt, D. L.
Markowitz, L.Lasterb - Headgear versus function
regulator in the early treatment of Class II, Division 1
malocclusion:A randomized clinical trial. AJO 1998;113
(51-61.).
Stephen D. Keeling, Timothy T. Wheeler, Gregory J.
King, Cynthia W. Garvan - Anteroposterior skeletal and
dental changes after early Class II treatment with
bionators and headgear. AJO 1998;113:(40-50.).


Sheldon Baumrind, Edward L. Korn,Robert J.
Isaacson, Eugene E. West, Robert Molthen
:Quantitative analysis of orthodontic and
orthopedic effects of maxillary traction . AJO
1983 (84); 384-398.
McNamara, Brudon; Orthodontics and
dentofacial orthopedics. Pg – 361 – 375. 2 nd edtn,
Needham press, Inc; Ann Arbor, Michigan.


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