Headgears /fixed orthodontic courses /certified fixed orthodontic courses by Indian dental academy

HEADGEARS
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Definition:
A class of appliances characterised by the
extroral positions of activating elements and
supporting structure and having remotely
located responsive force.

History:
 More than 100 years ago Kingsley is reported to
have used occipital anchorage during treatment.
The "head cap" was described by Kingsley in 1866 and Farrar in the
1870's.
 In 1907, Angle referred to extraoral anchorage
and illustrated his occipital headgear and traction
bar, which he replaced with “Baker’s anchorage”.
 In seventh edition of his text, Angle described the
use of extroral traction combined with extraction
of upper premolars.

Kingsley’s headgear Angle’s headgear

 According to Breitner, in 1911 Oppenheim
introduced the concept of center of rotation of
a tooth as the point around which a tooth
would rotate when a force was applied to the
crown. Oppenheim also recognised that if a
force could be arranged so that it passed
through the center of rotation then a tooth,
such as a molar would move bodily.

 Since such bodily movement does not involve
tipping or rotation, the focal point for the force
to produce the translatory movement has
become known as the center of resistance.
 Kloehn took up the use of extraoral traction
following a publication by oppenheim in 1936
and must be given the credit for use of cervical
traction as 1st phase in 2 phase treatment of
class II and maxillary anterior crowding.
 Phase I was concerned with distalising the
maxillary I permanent molar before pubertal
growth spurt. www.indiandentalacademy.com

 To translate molar distally, Kloehn
advocated alternately tipping the
molar crowns and roots. Distal crown
tipping was produced by positioning
the outer bow of the face bow below
the center of resistance and distal
root tipping by positioning the ends
of the bow above the center of
resistance.
 Weber showed examples of
extraoral traction designed to
distalise mandibular teeth.
Kloehn – type headgear

 Appliances resembling chin cups have been in use since the
early 1800's. According to Graber, the early attempts with
the chin cup were not successful because of incomplete
knowledge of mandibular and facial growth, its use on
nongrowing patients, and an inadequate understanding of
the forces generated by the chin cup.
 Armstrong applied 500 Gm. of force via chin cups on 100
adolescent patients with mandibular prognathism. He
reported that half of his patients showed improvement in
the Class III profile, whereas none of the control, nontreated
patients showed any favorable change.

 Thilander treated sixty patients with chin cups for 1 to 6
years. A significant percentage of patients did not improve.
The patients who showed improvement were comparatively
young and showed favorable dental changes. The force
generated by the chin cup in his study was only 150 to 200
Gm.
 Graber, Chung, and Aoba reported results in patients
treated with chin cups for 12 to 14 hours each day with a
force of 1.5 to 2 pounds on each side. They showed that
mandibular growth could be redirected with a chin cup.
They asserted that continuous use of the appliance for a
long period or through active growth was necessary to
achieve stable results.

 Graber treated 35 Class III malocclusions in children
between the ages of 5 and 8 years with chin cup therapy for
3 years. He found that the therapy was particularly effective
in patients with increased vertical growth of the face.
 Several clinical studies in the past have noted that
treatment of patients in skeletal Class III should include
protraction of the maxilla with or without chin cups.
Oppenheim suggested a technique for moving the maxilla
forward. He noted that restriction of growth or distal
movement of the mandible was impossible.

 Kettle and Burhapp reported an appliance for cleft lip and palate which
successfully inhibited forward growth of the mandible and
simultaneously caused anterior movement of the maxilla.
 Nelson described an appliance which used anterior pull on the maxilla by
means of a football-type helmet. Haas showed downward and forward
movement of the maxilla as a result of palatal expansion. The maxillary
effect was enhanced by the use of Class III elastics from a chin cup to the
distal aspect of the palatal appliance.
 Delaire, Verdon, and Floor have extensively used a facial mask to protract
the maxilla anteriorly. Elastics generating forces of 1,000 to 2,000 Gm.
are used from distal of the maxillary molars to the wires of the mask to
move the maxilla anteriorly.

Types Of Headgear
 According to the means of attachment to teeth
1) Using face - bow, which slots into tubes soldered onto the
bridge of a removable appliance crib or tubes which form
an integral part of a band attachment or tubes which are
incorporated in the design of a functional appliance.
The face – bow is an inner – outer bow. Inner bow is
available either in 0.045” or 0.051” depending on the size
of headgear tube. Outer bow is usually 0.072”
2) J – hooks which can be directly attached onto the arch wire
in a fixed appliance or attached to hooks soldered onto the
labial bow of a removable appliance.

 According to force element
1) Elastic strap or elastic bands
2) Spring loaded
 According to direction of pull
a) Cervical pull
b) Straight pull
c) High pull (Occipital/parietal)
d) Reverse Pull or protraction headgear
e) Combination headgear
f) Interlandi which gives more options for force direction.
g) Chin cup -- occipital and vertical

 According to the purpose of usage:
A. growth modulators
1. Protractors 2. Retractors 3. To control vertical excess
A. reverse pull A. high pull A. chin cup
B. straight pull
C. cervical pull
D. combination
B. for space regaining
C. molar distalisation
D. intrusion of maxilla

High Pull Cervical pull Combination pull

Retraction head gear

COMPONENTS OF HEADGEAR:
The principal components are
• Force delivering unit: usually a facebow or a J hook that delivers
force to the intra oral location
• Force generating unit: this is the active unit- usually springs of
elastic bands
• Anchor unit: its location depends on the direction of the force
applied, and is usually from the neck or the head.
Force is transmitted to the dental arch by
• Facebow: the force is delivered to the first molar by the face bow
which is engaged in the buccal tube. It can be attached to
removable appliances also. The facebow has an inner and an outer
bow. The inner bow is available in either 0.045-0.051 inch,
dependent on the size of the headgear tubes on the first molars.
The outer bow is usually 0.072 inch.

The different methods of making the inner bow stop mesial to the
first molar buccal tube are
– u- loop: advantage is that the length of the arm can be
altered by adjusting the loop;
– Bayonet bend: horizontal inset bend that keeps the
anterior segment of the bow away from the brackets.
– Trevor Johnson Friction stops: stops can be fixed at
the desirable location by crimping/soldering it
– Stop screws: the position of these screws can be
changed and can be re-used.
Outer bow is attached to the anchor unit and can be of different types
depending on its length:
• srt- outer bow shorter than the inner bow
• m- outer bow almost the same length as that of the inner bow
• lo- outer bow is longer than the inner bow

• Force magnitude: Recommended force values per side for
– full permanent dentition – 400-600 gms
– early mixed dentition – 150-250 gms
– late mixed dentition – 300-400 gms
– Retention in permanent dentition – 150-400 gms.
• Duration: according to Graber, forces of 12-16 hour duration
applied as intermittent forces appear to be the most effective for
orthopedic changes. Because the headgear is tooth borne,
intermittent force minimizes tooth movement while still
providing for skeletal change. An intermittent heavy force is less
damaging to the periodontium and the teeth.
• Force direction or vector: this depends on the location of the
extraoral attachment and the location of the outer bow.

• Magnitude –
For dental changes-
– According to Kloehn (1961) & Jacobson (1967) -
guided by patient comfort.
– According to Berman (1976) – 450 gm/side (1lb).
– J-hook headgear applies- 170-226 gm initially
For Orthopedic changes –
– According to Klein, Poulton, Graber- 450-
900gm/side (1-2lb).
– Should not exceed total of 7 pounds force on
maxilla.

BIOMECHANICAL CONSIDERATIONS
 Mechanics describes the effects of forces on bodies and
can be generally divided into three areas: 1) statics 2)
Kinetics 3) strength of materials.
 Statics describes the effects of forces on bodies that are at
rest or have a constant velocity.
 Force is action of one body on another body that tends to
change or changes the shape of that second body.
 A force is equal to mass times acceleration (F = ma). Unit is
Newton or gram. Millisecond/s^2. Grams are substituted
for Newton in clinical orthodontics because the
contribution of acceleration to the magnitude of force is
clinically irrelevant.

 A force is a vector and is defined by the characteristics of
vectors, which have magnitude and direction.
 Magnitude of vectors represent its size. Direction is
described by the vector’s line of action and point of origin.
 The sum of two or more vectors is called resultant.
 Clinically, the determination of horizontal , vertical and
transverse components of a force improves the
understanding of the direction of tooth movement that
might be expected.

Center of resistance
 A free body can be considered to have a single point within it
where all of its mass is centered.
 The center of mass is the point through which an applied force
must pass for a free object to move linearly without any
rotation.
 Tooth is restrained body in which this center of mass is called
center of resistance. It can be described in each plane of
space. Single tooth, units of teeth, complete dental arches and
the jaws themselves each have center of resistance.
 In other words the center of resistance is the point on the
body where a single force would produce translation i.e ., all
points moving in parallel, straight lines

 The center of resistance of a tooth is dependent on the
root length and morphology, the number of roots, and
the level of alveolar bone support.
 The exact location of the center of resistance is not easily
identified. Analytical studies have determined that the
center of resistance for single rooted tooth with normal
alveolar bone levels is about one fourth to one third the
distance from the cementoenamel junction to the root
apex.
 Miki and Hirato found that the location of the center of
resistance of the midface of the human skull was between
the first and second upper premolars anteroposteriorly,
and between the lower margin of orbitale and distal apex
of the first molar vertically in the sagittal plane.
 It is distal to the lateral incisor roots for intrusive
movements of maxillary anterior teeth.

 In maxillary first molar the center of resistance is
estimated to be in the middle third of the root near the
junction of cervical third or approximately at the
trifurcation of the roots.
 The center of resistance should not be regarded as a
fixed point within a tooth, but rather as the composite
point of all factors, offering different components of
resistance to a certain force application.
1. The tooth anatomy and mass distribution within the
tooth
2. The structure of the periodontal attachment
3. The degree of bony surroundings
4. The adjacent teeth.

Center of resistance
of maxilla

 The point of application of a force is simply the point of
contact between the body being moved and the applied
force.
 Direction is indicated by the body of the arrow itself and
the arrowhead. Without the head of the arrow, the body
alone indicates the line of action. The sense is determined
by which end we put the arrowhead on.
 Since the movement of a tooth (or any object) is
determined by the net effect of all forces on it, it is
necessary to combine applied forces to determine a single
net force, or resultant.

 There may be a force on a tooth that we wish to break
up into components.
 For example, a cervical headgear to maxillary molars will
move the molars in both the occlusal and distal
directions. It may be useful to resolve the headgear
force into the components that are parallel and
perpendicular to the occlusal plane, in order to
determine the magnitude of force in each of these
directions.

Center of rotation
 The center of rotation of a body is a point around which the
body will rotate or tip.
 The center of rotation can be changed, being dependent on
external force application.
 When a force is applied to a tooth and its line of action does
not pass through center of rotation, then tipping will occur
around a center of rotation which may be located anywhere
between the center of resistance of the tooth and infinity.

Resolving a force into components
It is often useful to divide a single force
into components at right angles to each
other. Usually, the objective is to
determine how much force is being
delivered perpendicular and parallel to
the occlusal plane, Frankfort horizontal,
or the long axis of the tooth.

Moment of force
 Forces not acting through the center of resistance do not
solely produce linear motion.
 The moment of force results in some rotational movement.
The moment of force is the tendency for a force to produce
rotation.
 It is unrecognized in clinical orthodontics. Awareness of
moment of force is required to develop effective and efficient
appliance designs.
 Two variables determine the moment of force – the
magnitude of the force and the distance. Either one can be
manipulated by the clinician to achieve the desired force
systems. www.indiandentalacademy.com

Moment of a couple
 This is another method of achieving rotational
movements.
 A couple is two parallel forces of equal
magnitude acting in opposite directions and
separated by a distance.
 Direction is determined by following the
direction of either force around the center of
resistance to the origin of opposite force.

BIOMECHANICS OF HEADGEAR
 Understanding how to control the direction and magnitude of
the forces produced by various headgear designs is paramount
in achieving desirable clinical results.
 Decreasing the patient's length of treatment and improving
the treatment results would be only two of the benefits
derived from applying well-planned force systems.
 A method of analyzing force systems produced in the
anterior-posterior and vertical planes will aid the clinician.

 In 1971 Armstrong demonstrated the importance of the
precise control of magnitude, direction, and duration of
extraoral force to increase its efficiency and effectiveness in
treating malocclusions in the late mixed dentition.
 Gould has shown how changes in the inclination of the
facebow affect the direction of the force and ultimately the
direction of tooth movement.
 Greenspan presented reference charts elaborating the
different moments and forces produced with the various
headgear designs.

Moments (M) and forces produced by force
vectors applied at varying positions relative to
the center of resistance (CR) of a constrained
body in this case the maxillary 1st molar. The
vertical (V} and horizontal (H) forces are
proportional in magnitude to the legs of the
triangle that is constructed
. In (a) the vertical and horizontal components
of the force are approximately equal. The
moment's direction is counterclockwise since
the line of force is above CR. The magnitude of
M is the product of LF times the perpendicular
distance (identified as P)from LF to CR. LF goes
through CR in (b) thus there is no M produced.
The tooth will translate parallel to the line of
force. The posterior force component is larger
than the superior. The LF in (c) will produce a
posterior and interior movement. The
moment (P x LF) is below CR and is therefore
clockwise.

 The magnitude of the moment produced by the headgear is
calculated by multiplying the perpendicular distance (P)
from the LF to the CR by the magnitude of the force. Thus,
for a given force, the greater the distance from the CR that
the force is applied, the greater will be the moment.
 A comprehensive understanding of the potential,
limitations, and undesirable side-effects can be gained by
understanding the mechanical principles involved in its
application.
 We can now apply our basic principles to assess force
systems applied by various headgear designs.

Center of resistance of maxilla:
• Miki 1979 and Hirato
1984 reported that the
location of the center of
resistance in the midface of
the human skull is between
the first and second upper
premolars anteroposteriorly,
and between the lower
margin of orbitale and the
distal apex of the first molar
vertically in the sagittal
plane.

• Lee in AJO 1997 determined the Cres of the maxilla
using holographic inferometry. They found that the
Cres of the maxilla was located at the distal contacts of
the maxillary first molars, one half the distance from
the functional occlusal plane to the inferior border of
the orbit. Hence the application of 500 gms per side of
force applied 15 mm above the occlusal plane and
directed 200 downward from the occlusal plane
produced pure translatory movement of maxilla.
Protraction of maxilla below the CRes produces
counterclockwise rotation of the maxilla. They
suggested that by varying the force system, the amount
and direction of maxillary rotation might be controlled.

• The center of resistance of the
dentomaxillary complex when
viewed in the sagittal plane is
located on a line perpendicular to
functional occlusal plane at the
distal contact of first maxillary
molars. When viewed in the
frontal plane, there are two
centers of resistance since the
dentomaxillary complex is
essentially comprised of two
bones that articulate with each
other at the mid palatal suture. If
forces are applied in the presence
of a 0.036 stainless steel TPA or a
sutural expander, then the two
units act as a single unit.

Clinical location of the Cres: (angle
1999 Stanley Braun)
• The location of the Cres clinically is
important. This can be done by
holding an amalgam plugger or
similar instrument in the maxillary
vestibule when the teeth are in
occlusion and the soft tissues and
lips are relaxed. The amalgam
plugger is positioned at the Cres of
maxilla. The instrument is then
palpated externally and a mark is
made on the skin surface
corresponding to it. The procedure
is done for the other side also. The
outer bow may then be adjusted so
that the force vector passes through
this point.

• Tanne et al concluded that the Cres of the maxilla was located at
the posterosuperior ridge of the pterygomaxillary fissure. He
suggested that the nasomaxillary complex was suspended by a
sutural system similar to the desmodontal system of a tooth,
possessing a Cres.
• Since the handle for applying force to the maxilla is the teeth, a
given force vector must be analyzed relative to both the Cres of the
dental units (which lies between the bicuspid roots) as well as to the
Cres of the skeletal unit. If no rotational effect is desired, then the
force vector must pass through the Cres of both the skeletal and
dental units. The force passing through both centers of resistance
will lead to pure translatory reactive movement with the centers of
rotation at infinity.

• When planning the direction in which
the dental and skeletal units should
move to approach a given treatment
goal, the effect of growth on the
development of these structures must
also be considered. The force vector and
the growth vector together determine
the resultant vector of spatial
displacement. The tendency towards
extrusion or intrusion in the molar or
incisor regions will be determined by the
direction of force vector and notably by
the rotational tendencies derived from
the relation of the force vector to the
center of resistance.
The least rotational and vertical change is obtained in an
arrangement wherein the applied force vector passes through the
Cres of the upper arch and the maxilla and this is the desired
condition for vertical control.

Cervical Headgear
 The cervical (Kloehn) headgear is a device that many
orthodontists have used routinely in the great
majority of their headgear cases.
 It is composed of three basic parts: (1) molar bands
and tubes, (2) inner bow and outer bow soldered
together near the middle of the two bows, and (3) a
neckstrap that is placed around the back of the neck
to provide traction.
 This extraoral pull is generally applied bilaterally, for
three main purposes: (1) as a restraining force, (2) as a
retracting force, or (3) as a supplementary force.

 The cervical headgear is applied in early
treatment of Class II malocclusion to inhibit
forward displacement of the maxilla or maxillary
teeth, while the rest of the dentofacial structures
continue their normal growth.
 As demonstrated by Oppenheim, this can cause a
change in the intermaxillary relationship from
Class II to Class I.
 Perhaps the change in molar relationship is due
not so much to the distal force, but to the
clockwise moment that very effectively tips the
molar crown distally.

 The main disadvantage to the use of the cervical
headgear is that it normally will cause extrusion
of the upper molars.
 This movement is seldom desirable except in
treatment of patients with short lower facial
heights. These patients, it should be
remembered, are few and far between.
 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.

Force systems with cervical
headgear. OB (Outer bow)-A
lies along the LFO and therefore
only vertical and horizontal forces
will be produced no M. The
position of OB-B will produce an
extrusive F posterior F and
counterclockwise M since it is
above CR. Outer bows located
below the LFO will produce
posterior forces and smaller
extrusive forces since they are
closer vertically to the neckstrap
and clockwise moments.

 The different moments and forces produced by the
cervical headgear depend on the situation of the outer
bow in relation to the LFO. By definition, 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.
 If the outer bow is placed above this line (angle of above
20- 30 degree above occlusal plane), the moment
produced by the force will be in a counterclockwise
direction. On the other hand, 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. It should be noted though that
there is an exception to this rule.

 If the outer bow is located below (angle of less than 20 degree to
occlusal plane) 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.
 outer bow is short -- steepen the occlusal plane
 outer bow is long -- flatten the occlusal plane

If the teeth are banded
and stabilized, cervical
pull appliance,
produces a force below
both center of
resistance of maxilla
and the dentition.. The
distances of the force
vector to A and B
determine the center
of rotation (x).

Studies on cervical headgear:
• Cook et al in AJO 1994 studied growing children with Class II,
Division 1 malocclusions who were treated with two different
techniques: one group with orthopedic cervical headgear/lower
utility arch (CHG/LUA) and another with cervical headgear alone.
The outer bow was bent 200 upward and the inner bow was
expanded. A force of 450 gms was used on either side. The authors
found that CHG produced Class II correction through maxillary
orthopedic and orthodontic changes, did not cause the upper molar
to extrude beyond the amount seen with normal eruption, and did
not produce an opening rotation of the mandible even in those
patients who had dolichocephalic facial patterns.

• .
• Melsen et al in AJO 2003 studied the intramaxillary molar
displacement 7 years after treatment with Kloehn headgear and
cervical traction. Two groups of 10 patients were studied. In one
group, the outer bow was tilted upward by 200 and in another
group, it was tilted down by 200. In the group that had the outer
bow tilted downwards, molar correction was faster. In both the
groups, the maxilla was moved backward and downward. A
strong tendency of the molars to return to the key ridge was
demonstrated, and there was no evidence that the Class I
relationship obtained by extraoral traction was more stable than
that obtained by functional or intramaxillary appliances.

• Haralabakis 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.

• 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.

High Pull Headgear
 The high-pull headgear, like the cervical-pull, is analyzed
using the same principles of force and moment
production described before. 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 (angulated > 45 degree
to occlusal plane) moment produced will be
counterclockwise.
 On the other hand, if the outer bow is placed posterior to
this line (angulated less than 45 degree to occlusal plane),
the moment produced will be in a clockwise direction.

High-pull headgears produce
intrusive and posterior forces.
Locating the outer bow in front
of the LFO (A and D) will produce a
counterclockwise M while an OB
behind (B and C) will create a
clockwise M. An OB located on the
LFO would of course produce no
M.

 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.

Short outer bow angulated high to create
the headgear force line of action that is far
anterior to the unit’s centre of resistance.
This results in a force system at the unit’s
center of resistance with a moment that
tends to flatten the occlusal plane and
distal and intrusive force components.

With long outer bow such that the headgear
force’s line of action passes through the
unit’s center of resistance and therefore no
change in the cant of occlusal plane

Long outer bow. The equivalent force system
at the unit’s center of resistance has a
moment that tends to steepen the occlusal
plane and a force with intrusive and distal
components. May be necessary for class II
open bite patients.

Studies on high pull headgear:
• Firouz et al in AJO 1992 examined the skeletal and
dental effects of the high-pull extraoral appliance, when
the resultant force was directed through the level of
trifurcation of the maxillary molars. Patients wore the
headgear for a 6-month period, an average of 12 hours
a day. The authors found that by directing the force of
the headgear approximately through the center of
resistance of the maxillary molars, it was possible to
translate the molars in the direction of the applied
force. Hence both intrusion and distal movement of
the molars can be achieved at the same time..

• Burke and Jacobson in AJO 1992 evaluated vertical
changes in growing patients with high MPA Class II,
Division 1 malocclusions who were treated with
cervical and occipital headgears applied from different
angles relative to the occlusal plane. They found greater
vertical changes in pts with cervical HG. The changes
in occlusal plane between the two types of headgears
were most significant. Posterior maxillary dentoalveolar
changes between the two groups were significant.

Straight Pull Headgear or Interlandi or
Combination 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. www.indiandentalacademy.com

• 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).

The straight-pull headgear is versatile
in that the clinician has many
optional LFO's . In this case an OB
located on
the LFO would cause translation in a
posterior and slightly superior
direction. OB's above the LFO will
produce posterior and extrusive
forces and clockwise moments.
Placing the outer bow along an LFO
that Is parallel to the maxillary
occlusal plane will produce a pure
posterior translation.

 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.
 However, if the LFO cants up anteriorly (attachment
site of elastic is lower on headcap than at outer bow),
an extrusive force will be produced. 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.

Force’s line of action passes through
center of resistance. No moment
acting to change the cant of occlusal
plane, and there is pure distal force
passing through the center of
resistance.

 This configuration is typical for redirecting maxillary
horizontal growth in class II patients and /or to move
maxillary molars distally via translation.
 When a force is applied to a headgear with inner and
outer bows, one side effect is buccal expansion
component of forces, which act bilaterally.
 This side effect is often helpful in class II malocclusions
because it is often necessary to expand the posteriors
to maintain proper interception as the buccal segment
class II interrelationship is corrected.
 If such expansion is not required, it can be prevented
by using a transpalatal arch.

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. Due to the multiple notches
in the headcap, this headgear is also very versatile, as the LFO
orientation may be changed.
 However, upon establishing the LFO, our principles of
determining force systems produced remains unchanged.

The vertical-pull headgear is used
primarily when a large magnitude
of pure intrusion is needed. The
outer bow must be located on the
LFO to obtain pure intrusion (A).
An OB located anterior to the LFO
will produce an intrusive force and
a smaller posterior force and a
counterclockwise moment (B and
C). Locating the OB posterior to
LFO will cause intrusion a small
anterior force and a clockwise
moment (D and E).

 The head is divided into two components: the anterior
component from the LFO forward and the posterior
component located behind the LFO. If the outer bow is
placed anywhere in the anterior compartment, the
moment created will be counterclockwise, and the
forces produced will be intrusive and posterior.
 If the outer bow is placed anywhere in the posterior
section, the moment will be clockwise and the vertical
force will be intrusive, but the horizontal force will be
forward.
 If this latter force system is desired, it will require
inserting the inner bow into the buccal headgear tube
from the distal.

• 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.

• 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.

Asymmetric Headgear
 Right versus left asymmetries can be corrected using
transpalatal or lingual arches to correct asymmetric molar
axial inclinations. The same mechanism can be used to
correct asymmetric molar rotations.
 If buccal occlusion is asymmetric e.g. Class I on one side
and class II on the other side, without asymmetries either
in molar axial inclinations or in rotations, then it is most
logical to achieve the correction with asymmetric
headgear.
 Distal forces exist on both sides, but they are three times
greater on the long outer bow side than on the short
outer bow side.

 Lateral forces, directed toward the short outer
bow side exist with this headgear. Crossbite
development should be kept in mind.
 These are usually cervical or combination type.

 Suggestions to be noted with regard to the use of the
asymmetric cervical gear:
1. The differential in length of arms of face-bow need not
be great, only sufficient to alter the geometry so that the
resultant bisector crosses the molar line closer to the more
anteriorly positioned molar than to the other. Excessive
difference in arm lengths could increase the lateral forces.
2. The diameter of wires can be increased for greater
rigidity; it is suggested that the arch wire be 0.055 inch and
the face-bow 0.075 inch (the 0.075 inch face-bow is
approximately five times as stiff as the 0.050 inch one).
3. The arms of the face-bow should clear the cheeks so as
not to introduce more undesirable lateral forces.

Asymmetric Headgear forces

 Rigorous force analysis of the several cervical gears of
different design using elastic straps shows that the
fundamental principle involved in the distribution of the
forces to the right and left molars is the geometry of the
direction of the right and left forces emanating from the
cervical elastic band.
 If these forces are symmetrical with reference to the
midsagittal line of the head, then the distribution of the
reactionary forces at the right and left molars will be equal,
irrespective of the design of the rigid portions of the
appliance (or the point of attachment of face-bow to arch
wire).

 If the direction of forces from the cervical elastic band is
asymmetrical with respect to the midsagittal line of the head,
then the anterior-posterior components of the reactionary
forces on the right and left molars will be unequal, the molar
nearest the resultant of the two elastic band forces receiving
the greater force.
2. Small lateral forces on the molars are always developed by this
eccentric design. These forces can be manipulated to cause all
lateral reaction to occur on one side or the other by springing
the labial arch inward or outward, respectively.

•
Unilateral face-bows – Hershey (AJO 1981)
• Face-bows which successfully and predictably provide
an asymmetrical delivery of distal force to their inner-
bow terminals are termed "unilateral face-bows”.

• 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.

There are four types of unilateral face-
bow designs available:
 Power-arm face-bow. In this design,
one outer bow is longer and/or wider
than the other, with the longer or
wider bow tip located on the side
anticipated to receive the greater distal
force. While effective in producing
unilateral distal forces, the power-arm
face-bow also generates lateral forces
which tend to move the favored molar
tooth into lingual cross-bite and the
other molar into buccal cross-bite.
Soldered-offset face-bow. Here the outer bow is attached to
the inner bow by a fixed soldered joint placed on the side
favored to receive the greater distal force.

• Swivel-offset face-bow. In this design the outer bow is attached
to the inner bow through a swivel joint located in an offset
position on the side favored to receive the greater distal force.
• Spring-attachment face-bow. Here an open coil of spring is
wrapped around one of the inner-bow terminals of a
conventional bilateral face-bow. The coil is placed distal to the
stop on the side favored to receive the greater distal force.
• Yoshida et al in AJO 1998 evaluated the effects and side effects
of asymmetric face-bows. They suggested that the power arm
face-bow is thought to be relatively recommendable because it
showed an acceptable asymmetric effect and is easily fabricated
from a commercially available face-bow. They concluded that all
asymmetric face-bows generate lateral forces as side effects as
long as the force delivery system with a combination of an
asymmetric face-bow and a neck strap or head cap is applied.

Headgear to lower jaw
 Headgear bracket-tube combinations can be attached to
either lower first or second molar.
 If the bracket-tube combination is on the first molar, it is
advantageous to place the headgear tube occlusally.
 First molar is preferred since
1) The lingual arch is on the first molar and gives better
control.
2) It is easier for the patient.
 Possible directions are:
1. The posterior segments tend to move back
2. A positive moment will be produced, which will steepen
the occlusal plane.

J- hook Headgear
J-hooks to arch wire
 A line of pull attached to the incisor region of the arch wire and
passing occlusally to the center of the resistance will place a distally
directed force upon the maxillary teeth, but will also tip the occlusal
plane downwards at the incisor end of the arch.
 A line of pull through center of resistance will produce distal
movement of the maxillary arch without undesirable rotational
effects.
 A more vertical direction of pull, mesial and apical to center of
resistance produces an anti-clockwise moment and an intrusive
effect upon the incisor end of the arch wire
 Disadvantage is that the flexibility of arch wire results in unavoidable
deformations which subject the teeth near the attachment to diurnal
reversals of force application as the extraoral appliance is attached or
disengaged. Heavy arch wires minimize this rebound effect, but not
eliminated.

J-hooks to individual teeth
 If the center of resistance of a single tooth
coincides with the centroid the line of force of a J-
hook headgear intended to produce upright
bodily movement of an individual tooth should
ideally pass through this center of resistance.
 Most authorities suggest an occipitally directed
line of force to move maxillary canines distally.
But straight pull is suggested as it is difficult to
obey theoretical concepts when moving
mandibular canines.

Direction of Headgear Force
 Given by the line of action of force from the point of origin to
the point of application of force.
Anteroposterior Plane:
 Explained by linear vectors of force. An anteroposterior force
that does not pass through the occlusal plane will certainly
have a vertical component.
a) Force directed upwards above the occlusal plane has an
intrusive effect on maxilla.
b) Force directed downwards below the occlusal plane has an
extrusive effect on maxilla.
c) Force passing along Center of Resistance produces
translation. www.indiandentalacademy.com

d) Force away from center of resistance( mesially, distally,
apically, occlusally) produces a moment tending to change
the occlusal cant.
e) Magnitude of moment is determined by moment arm.
Greater the moment arm – closer the Center of rotation
moves towards canter of resistance and greater is the
moment.
f) Medium length of outer bow is chosen for translation.
g) Short / long outer bow chosen when moment is desired.

Vertical Plane:
a) Direction determined by the sense of the line of action.
b) Outer bow along the Center of resistance produces
translation.
c) Force apical / occlusal to center of resistance produces
moment ( Extrusive / intrusive / distal).
d) Magnitude dependent on the inclination of line of action.

Lateral Plane:
a) Shape or length of outer Bow has no effect on force
application provided the distance of point of attachment to
the midline axis are equal. Headgear tube placed buccal to
center of resistance.
b) Hence any force applied, passes buccal to center of resistance
tending to roll the molars, buccally on intrusion and palatally
on extrusion.
This rotatory tendency is directly proportional to the
perpendicular distance of buccal tube to center of resistance
(moment arm). Clinically this moment is countered using
1. Palatal bar
2. Rectangular headgear tubes

CLINICAL APPLICATIONS OF
HEADGEAR FORCE
 There are four main uses of headgear force
1. Anchorage control
2. Tooth movement
3. Orthopedic changes
4. Controlling the cant of the occlusal plane

Anchorage Control
 In class II treatment, headgear force can play a major role in
ensuring that buccal segment teeth do not move mesially when
anteriors are retracted.
 Intraoral mechanics often result in eruption of teeth.
 Headgear produces a vertical force greater than the force of side
effect
 Inner and outer bows can be of any shape, convolution, and
length.
 Only the angle and level of the final line of action after the strap
forces have been applied to know exactly the force of headgear
system.

Vertical force on molar tube, a
side effect of intraoral mechanics
Vertical component of occipital headgear
force negates extrusive intraoral force
side effect

 The reaction force from headgear is dissipated against the
bones of the cranial vault, thus adding the resistance of
these structures to the anchorage unit.
 The only problem with reinforcement outside the dental
arch is that springs within an arch provide constant
forces, whereas elastics from one arch to the other tend
to be intermittent, and extraoral force is likely to be even
more intermittent.
 For first molar extraction cases -Interlandi headgear to be
suitable and well tolerated

Tooth movement
 Adjustment of outer bow such that a horizontal force is
produced that passes through the center of resistance of
maxillary first molar and the patient wears the headgear at a
level of 14 hours each night consistently, clinical experience
shows that the first molars will move distally 2mm in 24 months
without tipping.
 Distal tipping is not preferred as finite element studies have
shown that the stress levels at the periodontal ligament-bone
and tooth interfaces are beyond acceptable limits even when
tipping forces are very light.

Intrusion in deep bite cases
 Headgear can be used in adjunct to upper utility arch. High pull
headgear allows more intrusive control permitting maximal incisor
movement whilst minimizing possible molar tipping and also used
to deliver orthopedic force on developed premaxillary segment.
 120 to 150 g force is delivered.
Distalization of molars
 Headgear is the obvious choice. Fill time wear is necessary. Molar
extrusion should be avoided so straight pull or high pull is used and
not cervical.
 Force – 300g on each side.
 Unilateral molar distalization in unilateral class II can be achieved by
asymmetric cervical headgear

Canine retraction using
direct headgear force
 Headgear using four
hooks is used, which over
a base arch wire 19 x 25
steel.
 200 g of force supplied to
each point of attachment
to slide the canines
posteriorly

Orthopedic changes
 If the headgear is applied through
the center of resistance of
maxilla, which is in the
posterosuperior part of maxilla.
Determined clinically by dropping
a line vertically 10mm from the
outer canthus of eye and making
a horizontal from that point to
meet the pupil line in front of the
face.

 If a preadolescent patient wears the headgear at least 12
hours each night , the forward component of maxillary
growth is redirected.
Effects of orthopedic forces on maxilla
 Cervical traction produces stresses along the frontal
process of maxilla, zygomaticofrontal suture, and the
junction of the palatine bones, areas where high-pull
traction produced no observable effect. Only the high-
pull headgear produces stress at the anterior junction of
maxillae (anterior nasal spine).

Pterygoid plates of the sphenoid
 High stress develops upon activation.
 These stresses begin in the middle of the posterior
curvature of the plates and just superior to their anterior
junction with the palatine bone and maxilla.
 As the force increases, the stresses progress superiorly
toward the body of the sphenoid bone.
Zygomatic arches
 Cervical and high pull both produce similar stress .
 Starts at the inferior border of the zygomaticotemporal
suture and proceeds posteriorly along the zygomatic
process of temporal bone.
 Cervical force produces more intensity at lower load
level.

Junction of the maxilla with the lacrimal and ethmoid bones
 Both cervical and high pull produce a stress
concentration at the junction of the maxilla with the
lacrimal bones and with the orbital plates of ethmoid.
Maxillary teeth
 High stresses around maxillary molars with cervical
traction. These located around the middle third of the
mesiobuccal root and around distobuccal root at a
position toward apex.
 Also distal to second molar.
Frontal process of maxilla
 Stresses produced anterior to nasolacrimal foramen only
with cervical pull.

Zygomaticofrontal suture
 Just before maximum cervical load stress begins to
appear. Only with cervical pull.
Palate
 Cervical traction produces stress in posterior region
developing in the horizontal portion of palatine bones.
High pull has no effect.
Anterior junction of left and right maxillae
 Only high pull produces forces below the anterior nasal
spine and just lateral to the suture between the two
maxillae.

Sphenomaxillary suture- large compressive stresses.
Temporozygomatic suture- tensile normal stresses
Sphenozygomatic suture- large tensile stresses
Frontozygomatic suture- large compressive stress
Frontomaxillary suture- large tensile stress
 Sphenomaxillary and sphenozygomatic sutures, in
particular, resisted the posterior displacement of the
complex
 Stresses in the nasomaxillary sutures are varied by the
direction of headgear force, and the force applied in the
direction closest to that of the CRe may produce the most
effective sutural modification for controlling maxillary growth.

 Clinical studies have also demonstrated that extraoral force is
effective at restricting maxillary horizontal growth. In fact, several
studies are also available which indicate that headgear therapy can
reposition the maxillary complex posteriorly and inferiorly in
growing patients.
 Armstrong has demonstrated remarkably rapid (three to four
months) correction of Class II malocclusions in growing patients with
the use of continuous heavy forces parallel to the occlusal plane.
 Although not attached to the mandible or primarily aimed at
mandibular alteration, headgear treatment has been shown to
effect mandibular remodeling; the mandible and chin point have
been shown to relocate anteriorly in standard edgewise treatment.
Whether this represents a change which would not have occurred in
untreated individuals remains unclear.

 In Class II malocclusions with a fault in maxilla, profile
convexity of the upper jaw can be
a) Basal – large S-N-A angle
b) Dentoalveolar – increased sell-nasion-prosthion
(S-N_Pr) angle.
c) Dental – increased upper incisor to S-N plane
angle
 Maxillary basal prognathism requires heavy
orthopedic force. When evaluating the maxillary base,
the inclination should also be considered.
 An upward and forward inclination aggravates
maxillary protrusion. (Schwarz (1958) termed this as
pseudoprotrusion)

 A retro inclination (palatal plane tipped
anteriorly) can actually compensate for maxillary
prognathism.
 The control of the vertical dimension in this type
of malocclusion often depends on the inclination
of the maxillary base, especially if it is combined
with either a deep overbite or an open bite.
Combined activator – headgear therapy is
required.

Short face( skeletal Deep bite) Class II when growth
potential remains
 Goal is to increase face height and correct deep bite,
while allowing more eruption of the lower than the upper
teeth so that the occlusal plane rotates up posteriorly.
 Although cervical headgear tends to open the bite
anteriorly and therefore would help to correct a deep bite
problem, it differentially erupts the upper rather than the
lower molars and does not produce the desired change in
the orientation of occlusal plane.
 So functional appliances are useful in these patients.

Class II with normal face height and growth
potential
 Clinical studies show that in these patients , many
have deep bite due to excessive eruption of lower
incisors. And can be treated successfully by two
stage treatment.
 Stage I using headgear or functional appliances.
 Straight pull or high pull headgear is preferred
over cervical headgear, to reduce the elongation
of maxillary molars and better control the
inclination of the mandibular plane.

Skeletal open bite
 Characterized by excessive AFH. Major diagnostic criteria
are:
1. Short mandibular ramus
2. a rotation of the palatal plane down
posteriorly.
 Typical growth pattern shows vertical growth of the maxilla,
often more posteriorly than anteriorly, coupled with
downward-backward rotation of the mandible and
excessive eruption of maxillary and mandibular teeth.
 Only two thirds of the patients have actually an open bite –
in others excessive eruption of incisors keeps the bite
closed – but rotation of the mandible produces class II
malocclusion even if the mandible is normal in size and
severe class II if the mandible is small.

 Successful growth modification would be restraining
vertical development and encouraging anteroposterior
mandibular growth while controlling the eruption of
teeth in both jaws.
 High pull headgear to the maxillary first molars is the least
effective because it does not control the eruption of other
teeth. Furthermore use of molars as primary handle on
maxilla presents three problems:
1.Vertical component of force produces buccolingual
tipping .
2. The level of force application is limited by the tolerance
and response of the supporting tissues of these two
teeth.
3. Molar movement is the predominant dental change.

 High pull headgear with maxillary splint is better, as it
provides en masse dental control.
 Advantages
1. restraint of anteroinferior displacement of maxillary
complex with growth.
2. restraint of maxillary teeth
3. Disengagement corrects occlusal interferences,
facilitating correction of functional mandibular
displacements.
4. Direction and distribution of extraoral force application
to the maxilla may be adjusted over a broader range.
5. incisors can be retracted by including labial bow in the
design and full control over incisor tipping possible.
6. safety enhanced.

 But this does not control the eruption of lower teeth. Eruption of
lower teeth is controlled most readily by interocclusal bite blocks,
easily incorporated into a functional appliance. If the bite blocks
separates the teeth more than the freeway space, force is created
against both upper and lower teeth that opposes eruption.
 So the most effective treatment is a combination of a functional
appliance with bite blocks and high pull headgear.
 If cervical (Kloehn type) headgear is used, the maxillary molars are
driven distally into the “wedge” as the molars are extruded or tipped
down and back. The mandible is rotated down and back, increasing
the apparent mandibular retrusion and allowing compensatory
alveolodental growth to stabilize this undesirable sagittal change.
The maxillary incisors are usually tipped down and back at the same
time, restricting forward mandibular growth.
This result is now known as kloehn effect.

 With combined activator – headgear
treatment, high pull headgear attached to
activator exerts a retarding force on
horizontal and vertical maxillary growth
vectors.
 A high pull headgear does not tip the
palatal plane down and does not tip up the
anterior end of the palatal plane, which
tends to enhance maxillary incisor
protrusion and upper lip prominence.

 The headgear-activator has the following modes of action:
1. Intrusion and retraction of upper front teeth
2. Distalization of upper molars
3. Maxilla retraction
4. Mandibular growth stimulation, especially in the
brachyfacial group
5. Opening of the facial axis in the brachyfacial group
6. Maintenance of the facial axis in the dolichofacial
group
7. Minor, if any, tilting of lower incisors
8. Stopping lower incisor eruption
9. Stopping the descent of the palate

 Vertical control is obtained in two ways.
1.The untrimmed interocclusal acrylic acts as a bite block,
preventing molar eruption and clockwise mandibular
rotation.
2.The inclination of the outer facebow allows precise
control over the direction of force, according to the
following principles:
a)A force passing through the center of resistance
produces pure translation in the direction of the
force.
b)A force passing at a distance from the center of
resistance generates a moment, with a combined
effect of rotation (from the moment) and
translation (from the force).

HEADGEARS WITH OTHER APPLIANCES
HEADGEARS WITH REMOVABLE APPLIANCES:
Margolis acrylic cervico occipital anchorage:
• Margolis in 1976 incorporated extraoral force with removable
appliances for pts with class II malocclusions, using them both in
active and retentive phases of treatment. The Margolis appliance is
called an ACCO. Modified maxillary removable Hawley type
appliance permits the use of extraoral forces against the maxillary
dentition. Multiple ball end clasps and occlusal coverage can
increase the resistance to dislodgement by extraoral traction.
Margolis used this appliance to hold the torque correction achieved
with fixed appliances. This appliance was later modified by the
addition of 1 mm buccal tubes to the labial wire and soldering them
vertically at the canine-lateral incisor embrasure to receive the J-
hook extraoral force arms. An inclined plane was added to eliminate
functional retrusion and free the mandible for all possible forward
growth.

• A new ACCO is made after
extraoral forces and inclined
plane have created a class I
buccal segment. The ACCO
should be worn both day and
night with a minimum of 12 hrs
nocturnal headgear wear.
ACCO can be continued to be
used as a retainer after active
treatment and extraoral force
can be applied as indicated with
the ACCO to treat any residual
sagittal abnormality or tendency
to return to original class II
relationship.

Jacobson’s splint
• Jacobson used a splint similar to the
ACCO with extra oral traction for
correction of mild class II
malocclusions. The reduction in
overjet and the sagittal discrepancy
reduce the deforming action of the
abnormal perioral muscle function.
The force magnitude for this type
of removable appliance must not be
too great to prevent dislodgement
of the appliance.

• The direction of pull of the extra oral force should coincide roughly
with that of the Y-axis or a line extending from the symphysis to a
point 1.5 cm in front of the external auditory meatus. This prevents
the unfavorable basal maxillary tipping and extrusion of teeth. The
Jacobson craniomaxillary splint is used with occlusal coverage to aid
in retention and to prevent maxillary eruption while allowing
unimpeded upward and forward eruption of the mandibular buccal
segment that assists in sagittal correction.

Verdon combination appliance:
• An appliance similar to Jacobson’s splint was used. The
basic appliance of choice is a modified active plate. The
major objective is to effect a change through a
distalising influence on the maxillary arch leaving the
mandibular arch alone. An occipital headcap is used to
prevent tipping down the anterior palatal plane. A
cervical strap can be used but the force values are
significantly smaller, producing more dentoalveolar and
less basal effects.

HEADGEAR WITH FIXED APPLIANCES:
Edgewise appliance:
• Various types of headgears are used with the edgewise
appliance depending on the type of malocclusion and the stage of
treatment for effecting dental and skeletal changes.
• Kloehn type of headgear is the type most commonly used
mainly to reinforce anchorage. In growing patients, it produces
skeletal changes if high forces are used. The end of the outer bow is
bent up at an angle of 150 to prevent tipping of molars. This
produces opening of the bite due to extrusion of molars. Hence it
should only be used in patients with normal or deep overbites. In
patients with normal or low mandibular plane angles, kloehn face
bow can be used to obtain skeletal corrections.

• Straight pull headgear is used on the upper arch if
extrusion of the teeth is not desired. This type is used
on the upper arch during retraction of the canines and
incisors.
• High pull headgear with facebow is used to intrude
molars in selected cases of open bites.
• Intrusion of buccal teeth produces a rotation of
mandible thereby closing the openbite and reducing the
LAFH.
• High pull headgear using J-hook can be used in the
anterior segment for deep bite correction and for
correction of gummy smiles.

Straight wire appliance:
• When anchorage is critical, the anterior teeth are
retracted by the use of a modified Asher’s face bow
which can be hooked either to a neck strap to retract
the lower or upper anteriors or an anterior high pull
headcap to retract and intrude the upper incisors.
• Ashers high pull facebow with headcap is used to
retract the incisors using 12-15 oz of force.

Begg appliance:
• Extraoral forces are usually not required with begg
since begg mechanics minimizes the need for anchorage
conservation. However, headgears can be used in
isolated cases for distalisation of teeth or when
orthopedic control of maxilla is favored over extraction
or orthognathic surgery. Such indications would include
severe skeletal class II problems with high ANB
differences combined with excessive maxillary
protrusion. Headgear would also be indicated in non-
extraction cases requiring distal positioning of the
posterior teeth or maxilla to produce an acceptable
anteroposterior dental and skeletal relationship.

Level anchorage system:
• High pull face bow headgear is used to the
maxillary molar or a high pull J hook headgear attached
to the maxillary area, with 1 pound pressure on each
side, worn 12 hours per day by a growing patient will
reduce the ANB approximately by 10. Anchorage space
in the lower arch needed to correct the ANB angle is
reduced by approximately 1 mm for each 6 months of
headgear wear.

HEADGEARS WITH FUNCTIONAL APPLIANCES
Headgears with activator
• Levin et al in AJO 1985
reported the use of a cervical
headgear with the activator. A
cervical HG with a long outer
bow applying a force of 400
gms was used. It was concluded
that activator cervical headgear
therapy results in a simulation of
normal mandibular occlusal
development and a redirection
of maxillary dentoalveolar
development. Mesofacial and
brachyfacial types appeared to
respond most favorably to
treatment.

• Pfeiffer in AJO 1982 described the combination activator
— cervical headgear therapy. They preferred to use cervical
headgear, where necessary, for two reasons: (1) to extrude
maxillary molars, and (2) to apply orthopedic traction to the
maxilla and an activator to induce orthopedic mandibular
changes, restrain maxillary growth, and cause selective eruption
of teeth.
• Cura et al in AJO 1996 compared the effects of activator
and activator with HG therepy. A high pull head gear was used
with a force of 400 gms per side for 17 hrs a day. They found
greater improvement in the sagittal base relationship in cases
treated with combination therapy than in patients who were
treated with activator alone.

• Stockli and Teusher in their combination therapy said that
vertical and sagittal control of maxillary growth was essential in the
management of class II patients. Their activator HG combination
achieved control in all the three planes of space. A high pull HG
was used for depression of molars and vertical control of the
maxilla.

Headgears with herbst appliance.
• Was first reported by weislander in AJO 1984. It is
indicated only in cases of severe class II MO in early mixed
dentition. In order to transfer as much force as possible to the
base of the maxilla, splints may be used with an attempt to
distribute the force over the total dentoalveolar area for better
anchorage purposes. Orthopedic forces in human beings, usually
in the magnitude of 500 to 1,000 gm of pressure on each side
were suggested. When the total maxillary dental arch is used as
anchorage, forces up to 1,500 gm on each side can be applied
without discomfort to the patient. In most cases treated in the
mixed dentition, appliances were constructed for nighttime wear
only, and 12 to 18 hours of wear gave maximum treatment effect.
The orthopedic effect of treatment may increase if proper
anchorage is used and if the appliance is worn 24 hours.

• Weislander in AJO 1993 evaluated the effect of treatment and
retention on a group of consecutive cases several years out of
retention and to compare the initial changes during Herbst treatment
with the long-term situation 8 years after treatment. An average
increase of 2mm was found in the mandibular body length. Prolonged
retention with activator was needed to minimize relapse. Findings
indicated that maxillary sutural remodeling might be more receptive
long-term to orthopedic treatment than the mandibular condylar
growth process.
• Schiavoni in AJO 1992 evaluated the possibility of controlling
vertical dimension by using Herbst appliance and high pull headgear
in hyperdivergent facial patterns. The high-pull headgear had an
orthopedic restriction of the maxillary vertical development rather
than an effect on the sagittal plane. Elimination of anterior inferences
by orthodontic repositioning of the front teeth and preventing
extrusion of the posterior teeth allowed an anterior rotation of the
mandible, with improvement of the sagittal correction and beneficial
reduction in lower face height.

• Rabie and Hagg in Sem
Orthod 2003 investigated the effect
of adding HG to the herbst appliance
and in the retention period. A high
pull HG whose outer bow was
adjusted to be 300 above the occlusal
plane was used. The HG delivered a
force of 400-500 gms. Results
showed that the maxillary restraint
and improvement in jaw base was
greater in patients who had HG
during the treatment period. Rotation
of the palatal plane was seen in the
herbst group but not the HG- herbst
group. The authors concluded that
adding HG to the herbst resulted in
increased orthopedic effect on the
maxilla and a large increase in the jaw
base relationship. www.indiandentalacademy.com

Headgears with Bionator
• Dahan et al in AJO 1989 described
the use of a bioactivator with high pull
headgear for treatment of class II
division I malocclusion cases. High-pull
headgear was adjusted to the buccal tube
units of the multianchorage system. The
headgear was worn every night (8 to 10
hours) during the first year of treatment.
They concluded that the combination of a bimaxillary appliance with
extraoral forces leads to rapid changes in the correction of Class II,
Division 1 skeletal conditions.

Headgears and Twin block
• Parkin and sandler in AJO
2001 compared the effects of two
modifications of twin block. The
effect of twin block appliance
modified by the incorporation of
a high pull headgear and torquing
springs positioned on the
maxillary incisors was studied.
The headgear force was directed at the Cres of the maxilla in an
attempt to control the vertical position of the maxilla. Flying
headgear tubes situated next to the maxillary second premolars
were used to apply a force of 400 gm per side, worn for 120
hours per week.

• They found that in pts with headgear, the maxillary plane
appeared to have rotated in an anticlockwise direction.
Vertical eruption of the maxillary molars was restricted by
headgear. A restraint in the anteroposterior position of the
maxilla was demonstrated. The authors concluded that the
addition of high pull headgear in patients with twin block
allowed effective vertical and sagittal control of the
maxilla with no increase in LFH/TFH.

Headgears with frankel appliance:
• Owen et al in JCO 1985
modified the FR by adding
posterior bite blocks and a
headgear for the control of the
posterior maxilla. A high pull
headgear was used for posterior
maxillary control. The modified
function regulator appeared to
offer advantages in combining
functional jaw orthopedics with
directional force headgear in the
early comprehensive treatment of
long face patients. www.indiandentalacademy.com

• They suggested that the vertical dimension or
anterior facial height (ANS-Me) could be held constant
or even decreased through the holding or intrusion of
the upper molars. Although no condylar growth was
demonstrated in this study, there was a potential for
increased mandibular growth.

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

• 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

• 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.

HEADGEARS FOR MOLAR DISTALISATION:
According to Nanda et al
• By directing the forces through the Cres of the maxillary
molars, intrusion and distalisation of molars can be
achieved.
• An average of 500 gms was suggested to translate the
molars distally and at the same time initiate maxillary
changes that are normally associated with high force
levels.
• If the headgear is used for a short period of 6 months
with good patient co-operation, significant dental
improvement in the class II molar relation can be
achieved.

Cephalometric guidelines for headgear
treatment
Direction of growth
Broad mandibular base and ascending ramus together with a very marked,
thick symphysis suggest a change in direction toward horizontal growth.
Narrow mandible and thin symphysis – vertical growth.
Growth potential
If the mandible is too small in class II in a growing individual, growth may
be expected to be quite considerable.
A well developed mandible in a posterior position must be considered to
offer poor prospects for successful correction of class II malocclusion,
except in cases with translation.
Convexity of nasomaxillary complex
SNA angle large ANS far anterior to N- Pog line.
Ante – inclination of maxilla (large J angle) will increase protrusion
(pseudo protrusion). Midface (N – Sn) is short. Extreme case – Microrhinal
dysplasia. www.indiandentalacademy.com

Timing of headgear treatment
 The most optimum treatment time is between
maturational stages SMI 4 to 7, a very high
velocity period of growth.
 The next most desirable time to treat is during
the accelerating velocity period between stages
SMI 1 to 3
 the least desirable time is during the decelerating
velocity period between maturational stages SMI
8 to 11. This information is clinically useful for all
growth related mechanics of treatment,
retention, and orthosurgical timing of therapy.

SELECTION GUIDELINES FOR HEADGEAR TYPES
1. Cervical pull face bow headgear
a) A large horizontal component of force is present, but
also a vertical component, which may extrude the
maxillary molar.
b) Molar extrusion may assist the treatment of class II, low
Frankfurt-mandibular angle, increased overbite cases.
c) Limited molar extrusion will probably not affect class II
cases with an average FMA, particularly if angle SNB is
average. Facial changes must be monitored during
treatment.
d) High FMA, class II cases, should never be subjected to
this line of force to avoid the creation of an unfavorable
mandibular rotation, with consequent ill effects upon
the face.

e) Outer arms bent downwards will tilt distally the
crowns of mesially tilted molars.
f) Outer arms bent upwards appear to result in more
upright, but less distal movement.
2. Straight pull face bow headgear
a) A very large horizontal component of force is
present.
b) A small vertical force component may produce mild
extrusion.
c) It will probably effect less distal movement of the
root, than of the crown.

3. High pull face bow headgear
a) Root axial control may be achieved to produce
effective upright distal movement of the molar teeth
or tilting as is required.
b) The molar will be intruded and the ratio between
distal and intrusive movement will depend upon the
steepness of the angle of pull.
c) It is a suitable line of force to move distally the fully
banded maxillary arch, intruding the molar end and
less certainly the incisor end.
d) In high FMA, class II cases, with reduced or even
average overbite, distal movement with extrusion of
maxillary molars is probably to be avoided, and high
pull anchorage may be advantageous.

e) In high FMA, class II cases, with anterior open bite, a
vertical line of force commencing occlusally and passing
distally to the center of resistance, will intrude the
maxillary molars and may rotate downwards the incisal
end of a fully banded arch.
4. Cervical pull J-hook headgear
a) Used to the maxillary incisor region, a tipping of the
incisal end of the occlusal plane in a downward direction
may result, with a reduction of open bite. However molar
extrusion is probable.
b) Used to the mandibular incisor region, it may depress the
chin creating more vertical space into which maxillary
teeth may be extruded during class III treatment. The
resultant downward and backward rotation reduces the
antero-posterior basal discrepancy.

5. Straight pull J-hook headgear
a) It is suitable for moving mandibular canines distally.
b) Attached to the maxillary incisor region, distal arch
movement occurs, but a downward tipping of the incisal
end of the arch is probable.
6. High pull j-hook headgear
a) A line of force to the maxillary incisor region passing
mesial and apical to the center of resistance, will
intrude the upper incisors, move them distally and
augment palatal root torque.
b) A line of force to the maxillary incisor region passing
through the center of resistance will have a large distal
and smaller intrusive effect upon the incisor region.
Theoretically this may produce the greatest orthopedic
effect. www.indiandentalacademy.com

c) A line of force to the maxillary incisor region passing occlusal
to the center of resistance may have a mild downward tipping
effect upon the incisal end of the occlusal plane.
d) It is the direction of choice for distal movement of maxillary
canines or to sliding jigs for maxillary molar distal movement or
anchorage

The following are to be followed with headgear treatment:
1. Routine use of Visual Treatment Objective of some type
of comparative treatment goal.
2. Routine cephalometric x-rays at six to nine month
intervals to evaluate treatment changes and progress.
3. Knowledge of normal growth and the effects of
orthodontic treatment and extraoral forces to the patient.
4. A prediction of the future skeletal pattern of the patient,
the accuracy of which can be enhanced by the control that
can be exerted upon the skeletal pattern by proper
orthodontic and orthopedic treatment.

Components of face bow system
 Maxillary molar tubes are positioned
gingivally or occlusally on the molar bracket.
 The advantage to gingival placement is that
the tube is closer to the center of rotation
of molar, which reduces molar tipping.

The outer Bow (Wisker Bow)
 The outer bow ends anteriorly to the ears. Then when a patient
wears a combination face bow, the high pull portion will fit
naturally in front of the ears and the neck strap will attach below
the ears.
 In all cases, the outer bow is positioned in the horizontal plane
parallel to and even with the inner bow. 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 t
 When using a high pull retractor, the end of the outer bow
should coincide with the location of the maxillary first molars. It
is bent 60 degree angle superior to horizontal.
 The outer bow must be adjusted to fit the face of the patient.
Should be 5 to 10mm away from cheeks.

Outer bow resting passively between
lips
Outer bow several millimeters from
cheek

Length of outer bow is critical to the desired changes

 Proper adjustment of the inner bow will allow the wire to slide
in and out of the headgear tubes easily when the posterior
strap is not attached.
 Adjustments to the inner bow can be made in six directions:
bucco-lingually, superior- inferiorly, antero-posteriorly.
 First Bucco-lingual force is controlled.
 If the bow is inserted into one headgear tube, the other bow
end should be expanded approximately 5mm buccal to the
opposite tube.
 This expansion bend is made near the anterior portion of the
inner bow.
The Inner Bow

As a class II molar relationship is corrected, the relative
forward movement of the lower arch will produce a cross
bite tendency unless the upper arch width is expanded

Vertical adjustments can be made at molar adjustment loops

 If maxillary arch expansion is desired and a face bow is
used, a greater amount of expansive force must be built
into the inner bow. Inner bow is expanded more than
5mm.
 Secondly, in superior-inferior direction
 When the patient closes his mouth and relaxes his lips, the
anterior junction of the inner and outer bows should not
be pushing either lip in vertical direction.
 The bow should be in a passive position between the lips.
In order to maintain this position , the posterior ends of
the inner bow are adjusted superiorly or inferiorly.

 Lastly, antero-posterior adjustment.
 Inner-outer bow junction is just anterior to
the point where the lips seal.
 It may be necessary to enlarge or constrict the
loops in the inner bow to achieve this
position.

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.

 The potential of these devices to injure the face has been
recognized by the orthodontic community. Among the
possible sites of injury are the eyes.
 With improper handling, headgear appliances can result
in penetrating ocular injuries. The removable metallic
bow contains two projections that normally fit into the
mouth. However, when pulled forward, the bow can slip
from the oral cavity, retract under tension, and strike the
eyes with substantial force.
 Spectacles may provide protection, but it is also possible
that these metallic projections under tension could slip
beneath the frames and strike the eyes. The distance
between these two projections approximates the
interpupillary distance. Thus, there is an added risk of
bilateral ocular injuries

 In general, bacterial endophthalmitis occurs infrequently after
penetrating ocular injuries. However, in headgear injuries, the risk of
bacterial infection is extremely high because the penetrating object is
contaminated with saliva.
 The normal flora of the oral cavity consists of a multitude of
organisms, including S viridans, anaerobic and aerobic staphylococci,
gram-negative diplococci (Neisseria and Branhamella species),
Corynebacterium, Lactobacillus, anaerobic Vibrio, and Actinomyces
species. Thus, patients are susceptible to mixed-flora infections.
 In response to the occurrence of facial injuries, manufacturers are
developing new appliances with devices that prevent disengagement
or that release the elastic traction when sharp forces are applied

Samuels et al AJO 1996 in a review of orthodontic
face-bow injuries and safety equipment found that
the cause of the injuries could be roughly grouped
into four categories.
1. Accidental disengagement when the child was
playing while wearing the headgear
2. Incorrect handling by the child during the fitting or
removal of the headgear
3. Deliberate disengagement of the headgear caused
by another child
4. Unintentional disengagement or detachment of the
headgear during sleep.

• Injuries have occurred with both removable &
fixed appliances.
• Ranged in severity from minor lacerations to
loss of eye.
• All occurred in children aged between 9-14
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

Safety release
headgear with
spring
mechanism which
breaks apart
when excessive

• 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.

• Patient should be warned- soreness to be expected
during 1st week till supporting bone adapts to force.
• Next visit after 2wks - verify patient compliance.
• Then after 1 month next visit. Frequent visits increase
compliance
• Indicators to assess headgear wear-
– Ease with which patient can place & remove appliance
– Mobility of maxillary molar.
– Signs of wear of extra oral attachment components &
calculus on face-bow after few months of wear.
– Improvement in A-P relationship.
– Patient keeps a daily diary of length of use

Thank you
Leader in continuing dental education

Headgears /fixed orthodontic courses /certified fixed orthodontic courses by Indian dental academy

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