Anchorage in orthodontics- Dr Lubna Abu Alrub

Anchorage in orthodontics
Dr-Lubna Mohammad Abu Al-Rub
Supervised by :
1. Dr-Ahmad Al-Tarawneh
2. Dr-Raed Al-Rbata
3. Dr-Nancy Al-sarairah

Outline
 Definition of anchorage.
 Optimal force in orthodontics
 assessment of anchorage demands
 Types of anchorage
 Ways to reinforce anchorage
 Orthodontic perscriptions and anchorage
 Measuring anchorage
 Monitering anchorage
 Anchorge in 3 planes of space/clinical
scenarios

Anchorage
 Websters international dictionary
defines anchorage as “ a secure hold
suffiecient to resisit a heavy pull “

Anchorage
 the resistance to unwanted tooth
movement (proffit 2000)or those sites
that provide resistance to the reactive
forces generated on activation of any
orthodontic appliance to control
unwanted tooth
movement(mitchell2001)

 For example, if an upper canine is
being retracted, the force applied to
the tooth must be resisted by an equal
and opposite force in the other
direction. This equal and opposite
force is known as anchorage.

 If an upper canine is to be retracted, with bodily movement
using a fixed appliance.
 the force applied to the tooth will be approximately 100 g.
 Forces in the opposite direction varying from 67g on the first
permanent molar to 33 g on the upper second premolar.
 Resist this Low levels will produce negligible tooth
movement and the effect of a light force of 100 g would be to
retract the canine with minimal anterior unwanted movement
of the anchored teeth.

 However, if the force level is increased to say 300 g.
 the force levels on the anchor teeth increase dramatically to the
level where unwanted tooth movements will occur ”loss of
anchorage”.
 Although the canine may move a little distally, the buccal teeth will
also move mesially.
 Space for the canine retraction may be eliminated with insufficient
space left for alignment of the anterior teeth.

Optimal force level in
orthodontics
 Optimal force level in orthodontics
defined as a mechanical input that
leads to maximum rate of tooth
movement with minimal irreversible
damage to the root, periodontal
ligament and alveolar bone. The
theory of optimum forces was
proposed by Storcy and Smith in
1952.

 Force threshold is defined as the
minimum force to produce
movements. Classically, ideal forces in
orthodontic tooth movement are those
that just overcome capillary blood
pressure 20-25gm/cm3 as per
Schwartz (1932).

Assessment of the anchorage
demand
1. General factors
 Age
 Medical condition
 Medication
 Individual variation
 Patient compliances

Assessment of anchorage
demands
2.Treatment plan factors
o Treatment aims: correction of molar
relationship after extraction require little
anchorage than correction of sever OJ or
crowding
o Type of movement required, bodily
movement require higher anchorage
demand than tipping movement.
o Extraction pattern, the more posterior
teeth extracted the more anchorage
demand will be.

demands
3.Treatment mechanics factors
o Appliance prescription: MBT less
anchorage demand than Roth and
Andrews prescription
o Appliance type, tip edge appliance
required less anchorage demand than
andrews straight wire appliance. URA
is less anchorage demanding than FA.
o Mechanotherapy: heavy force need
more anchorage.

demands
4. Intra-arch relationship
 Involved arch: The maxillary arch is
particularly susceptible to anchorage loss.
This is probably due to a combination of
factors:
1. Maxillary anterior teeth are bigger and
wider.
2. The upper anterior brackets have more
tipping built into than the lower anterior
brackets.
3. The upper incisors require more torque
control and bodily movement than the lower
incisors, which only require distal tipping or
uprighling.
4. Mandibular bone is harder than cancelous

demands
 Amount of crowding: sever crowding
requires more anchorage
 Location of crowding, the more distance
between anchor unit from the irregular teeth
to be align or retracted, the more anchorage
demand.
 Angulation of the teeth, distally angulated
canines required higher anchorage to align
and retract them than upright or mesially
inclined canines.
 Inclination of the teeth, palatally tipped
upper incisor require more anchorage to
retract them than proclined one

demands
5. Inter-arch relationship
o Amount of OB
o Amount of OJ
o Amount of centreline problem
o Skeletal relationship AP: camouflaging
moderate to severe skeletal relationship
is more anchorage demanding than mild
cases
o Skeletal relationship vertically, high
angle cases require higher anchorage
demand because:

Assessment of anchorage needs
interarch relationship
 Bone is less dense than bone of low
angle case which favour teeth
movement and anchorage loss
 The direction of the occlusal plane
favour the mesial movement of the
anchor teeth
 A weaker muscle fibres associated
with high angle case produce less
occlusal interlocking than normal.

demands
6.Occlusal interlock
Some extraction patterns e.g. upper
first and lower second premolars can
create useful interlocking of the dentition
and increase the root surface area
resisting a loss of upper arch posterior
anchorage.
Conversely upper canines stuck
mesial to lower canines can lose upper
arch anchorage as can attempted
reduction of an overjet in the presence of a
complete overbite

Types of anchorage
A. Intraoral
o Intramaxillary
1. originating from the teeth : simple , compound , stationary ,
reciprocal .
2. Originating from the soft tissues
3. Originating from the bone
o intermaxillary
1. Myofunctional appliances
2. Inetrmaxillary elastics
B. Extraoral ; Headgear

Intraoral anchorage
1.Intramaxillary
A.Originating from teeth
 Simple anchorage (one tooth providing
anchorage to other tooth)

 Compound anchorage (group of
teeth providing anchorage to one tooth
or smaller number of teeth.

 Stationary
anchorage
(refers to the
advantage that
can be obtained
by putting bodily
movement of one
group of teeth
against tipping of
another).

Intraoral anchorage
 Differential anchorage: mean
moving the teeth by tipping them first
then upright them to reduce the stress
on the anchor teeth

Differential force theory
 Differential force theory: is a
combination of Stationary and
Differential anchorage.
 The active units are allowed to tip by
relying on the anchor units which are
hold by the effect of their bodily
reaction.
 Then the active units are uprighted.

Differential force theory
 It does however remain a theory which
is far from fully proven, although there
seems strong indirect evidence that
the differential force theory has
substance.
 This theory states that within limits,
the rate of tooth movement is related
to the applied force per unit root
surface area. i.e. within a certain
range of force, a given force will result
in less tooth movement if spread over
a larger number of teeth.

 Reciprocal It may be that equal
movement of both the active and
reactive units is desirable, such as
expansion or closing a midline
diastema.

Types of anchorage
A. Extraoral ; Headgear
B. Intraoral
o Intramaxillary
1. originating from the teeth : simple , compound , stationary ,
reciprocal .
2. Originating from the soft tissues
3. Originating from the bone
o intermaxillary
1. Myofunctional appliances
2. Inetrmaxillary elastics

Intraoral anchorage
B.Originating from soft tissue
 Lip bumper
 Bone palatal vault like Nance and
URA

Lip bumper
 Muscular forces –lip bumper
It mainly consists of a thick round
stainless steel wire that fit in the headgear
tube of the molar band and stays away
from the labial surface of the incisor by the
effect of the loop mesial to the entrance to
the molar tube. The acrylic pad is
embedded in the anterior part of the wire
and act to actively displace the lip forward.
The reciprocal force of the displaced lip
will be transferred to the molars via the
heavy wire and result in molar uprighting
and distalisation

C. Originating from bone
 Skeletal or bone OA
(implants/miniscrews/plates)
 Cortical Anchorage

Orthodontic bone anchorage
devices
 Orthodontic bone anchorage devise
(BAD) can be defined as the use of
implants, plates, screws or screw-
retained devices inserted into bone to
provide resistance to unwanted tooth
movement (indirect anchorage) or a
point from which traction can be applied
(direct anchorage).
 Bone anchorage devices can broadly be
divided into two categories:
 Conventional osseointegrated implants.
 Temporary bone anchorage devices
(TAD’s).

Osteointegrated implants
 Conventional implants may provide a
useful point of absolute anchorage in
patients for whom an implant-born
restoration is planned following pre-
restorative orthodontics, or who
already have an implant-born
restoration in place

 . Orthodontic attachments can be
mounted on implants using temporary
copings, to allow them to be incorporated
into a fixed appliance (Ödman et al.,
1994). Whilst it is useful to have
conventional implants available for
anchorage control during pre-restorative
orthodontic treatment, it is important that
they are in the correct position, since
they cannot easily be re-sited later on.
Where the implant(s) are already in situ,
the teeth will have to be positioned
around them, which may not always give
the best result.

Temporary bone anchorage
devices (TAD’s)
 Osstiointegrated retained devises
 1-midpalate implants Mid-palatal implants are
designed to osseointegrate, but are surgically removed
following use.
2- onplantsa subperiosteal titanium alloy disk, 2 mm thick
and 10 mm wide, coated with hydroxyapatite.
Mechanically retained devises
1-Mini-plates (Maxillofacial bone plating kits) of
maxillofacial bone plates. In particular, the orthodontic
versions have transmucosal necks and customised heads
to facilitate their connection to fixed appliances
2-Mini-implants or mini-screw

Cortical anchorage:
 Rickets technique by intentionally bringing the
buccal roots of the anchor teeth into contact with
the cortical plates of bone thus increasing the
anchorage value of such teeth. It should be
appreciated that this process should be carried
out with great care and precision since
overzealous torque can produce root resorption
or in extreme cases cortical perforation.
(Brezniak & Wasserstein, 2008)
 The transpalatal arch, qaudrihleix & the lingual
arch. It also depends on the idea of compound-
cortical anchorage by increasing the number of
teeth in the anchorage system as well as cortical
bone anchorage theory. However there is a risk
of root resorption

Intermaxillary (from the opposing
arch) like
 Myofunctional appliance
 Intermaxillary elastic.

Functional appliances
Rely on Musculature forces, It must be remembered
that a reactionary mesially directed force occurs in
the mandible and the reactionary distally directed
force occurs in the maxilla during the use of the
functional appliance. This could lead to upper teeth
distalization and lower teeth mesialization

Fixed functional appliances
 Fixed functional appliances
These differ from fixed forms of class 2 traction
only in that the force is stored in the muscles and
ligaments rather than in the elasticity of a metal
spring.
 Types of fixed functional
appliance:
 •Herbst appliance
 •MARA appliance
 •Sabbagh appliance with spring element locked
 •(Fixed twin-block)
 •AdvanSync 2 molar-to-molar appliance

 Herbst appliance
MARA appliance

Fixed Functional appliances
 Functional appliances are another source of
intermaxillary anchorage. Herbst ( force
derived in muscles / ligaments)
 Whilst some clinicians may believe these
devices simply make the mandible grow, this
is not the case and whatever mandibular
growth does take place, is accompanied by
quite substantial movement of the dentition
over the apical base.
 This means that mesial tipping of the lower
and distal tipping of the upper teeth occurs.

Intermaxillary elastics
 This relies on using the
opposing arch to provide
anchorage to the other
arch. Care must be taken
to realise that
intermaxillary traction is
an inefficient method of
space closure and if
prolonged can lead to
excessive extrusion and
tipping of the anchor
teeth.

Intermaxillary elastics
 One popular example of utilizing intermaxillary
elastics is closing a mandibular premolar
extraction site , it would be possible to stabilize
all the teeth in the maxillary arch as one group so
that they could only move bodily and then run an
elastic from the upper posterior to the lower
anterior thus pitting forward movement of the
entire upper arch against distal movement of the
lower anterior segment .
 This can be described as stationary as well
 Bear in mind that elastic force from one arch to
the other tend to be intermittent whileother
sources such as HG can be described as more
constant.

Methods to reinforce
anchorage
4. Extraoral orthodontic anchorage
support :
 Example HG or PHG which get its
support from a very stable skeletal
structure outside the mouth like
cranium, occipital area and the chin.

Extraoral anchorage
o Headgear
 The force from the headgear is usually applied to
the teeth via a face-bow (Klöen bow)
 This is fitted either to tubes attached to the
appliance or integral with it as in the en masse
appliance.
 The direction by which the force is applied can be
varied depending on the type of headgear that is
fitted.

Cervical headgear
 This is applied via an elastic strap or spring, which runs
around the neck .
 It has the advantage of being relatively unobtrusive and easy
to fit.
 However, it does tend to extrude the upper molars and tip
them distally because of the downward and backward
direction of force.
 This later effect can be counteracted to some degree by
adjusting the height and length of the outer bow.
 Cervical headgear should not be attached to removable
appliances because it is prone to dislodge the appliance and
propel it to the back of the mouth.

Occipital headgear
 This is also known as high pull headgear and is applied
via an occipitally placed head-cap.
 It is easy to fit but is more obvious than the neck strap
and tends to roll off the head unless carefully adjusted.
 Because the force is in a more upward direction, there
is generally less distal tipping of the upper molar and
less extrusion, but also less distal movement than with
cervical headgear.
 The tipping and extrusion effect again depend on the
length and height of the outer bow.

Combination (variable) pull
headgear
 This applies a force part way between
cervical and occipital.
 It takes slightly longer to fit than either
cervical or occipital and is more
obtrusive.
 However it is secure and comfortable
and the vector of the force can be varied
to produce relatively less tipping and/or
extrusion.

Reverse pull headgear
 Reverse or protraction headgear is
useful for mesial movement of the
teeth.
 either to close spaces or help to
correct a reverse overjet.
 It does not employ a face-bow, which
is an advantage
 but instead employs intra-oral hooks
to which elastics are applied.

 Force level
 No well designed studies investigating the effects of differing force
levels.
 Force is inherently intermittent, so level probably less important than
direction.
 Anchorage : 200-250 gm /side for 10-12 hour
 Dental : 400-500 gm/side for 16 hours + assisting device.
 Orthopedic : 500-900 gm/side for 12-14 hours

 Hours of wear
 If headgear is prescribed, we would
favour using it only in bed at nights
and this has shown to increase the
patients cooperation with wearing
headgear.

Molars distalisation /assissting
headgear
 Magnets (Gianelly 1989)
 Coilspring distalisers eg Gianelly 1998
 Pendulum appliance (Hilgers 1992)
 Nudger (Cetlin & Ten Hoeve 1983)
 These devices incur a high level of
anchorage loss (OJ)
 Must be supported with HG or class II
 Some (eg Nudger) may cause excessive
molar tipping
 Nudger very useful in selected cases

 TADs or HG. Junqing in 2008 showed
again a better result by TADs in
comparison with HG.

anchorage
 The extent to which anchorage should
be reinforced by adding teeth to the
anchor unit depends on the tooth
movement to be achieved
 For significant differential tooth
movement , the ratio of the PDL area of
the anchor unit to the PDL area in the
tooth movement unit should be at least 2
to 1 without sliding and 4 to 1 with sliding
, anything less produce something close
to reciprocal movement especially if
force level is not well controlled.

anchorage
1) Compound anchorage: Include
more teeth in the anchor unit.
 In other words , subdivision of the
desired movement rather than dividing
the arch into more or less equal
segments

anchorage
3) Tipping and uprighting (Differential force theory):
 In the TipEdge or Begg principle the upper anterior
teeth are allowed to tip distally using the force of the
intermaxillary class II elastic, but the molar is prevented
from moving forward by a ‘tipback bend’.
 Additionally, the tipback bend helps to overcome the
vertical extrusive effect of the elastic on the anterior
teeth.
 However, it is not clear whether tipping and
subsequently uprighting a tooth consumes less
anchorage than achieving the same result with bodily
movement. More recently, a good study by Shpack ,
found that bodily retraction of a canine consumes the
same anchorage as tipping followed by uprighting and
incidentally, bodily retraction was more rapid by an
average of 38 days.

anchorage
3. Tipping and uprightening (diffrential
force theory)
In our familiar extraction site example this
would again require two steps in treatment
, first the anterior teeth would be tipped
distally bybeing pitted against mesial
bodily movement of posterior segments .
Allowing the teeth to tip as they slide along
the arch wire keeps the cntact angle
between the wire and the brackets small ,
this reduces binding and and keeps
resistance t sliding small.

anchorage
4.Palatal vault: Example URA & Nance
appliance which relies on the bone and
soft tissue anchorage
 Contact between the appliance and the
labial or lingual mucosa can increase
anchorage considerably for either fixed
or removable appliances.
 Contact between an orthodontic
appliance and the vault of the palate
provides resistance to mesial movement
of the posterior teeth

anchorage
 The anchorage provided by this
means is considerably greater if there
is a high vaulted palate, which will
produce a greater buttressing effect.

anchorage
 A shallow vaulted palate will provide
much less anchorage control because
the appliance will simply tend to slide
down the inclined plane of the palate

anchorage
 The mucosa and
underlying bone can
also be used when
fixed appliances are
used.
 For example a Nance
palatal arch. This is an
acrylic button that lies
on the most vertical
part of the palate
behind the upper
incisors and is added to
a trans-palatal arch.

anchorage
 These buttons are again of more
limited use if the palatal vault is
shallow.

Use of TPA as an achorage
aid
 Transverse anchorage
 Anterior posterior anchorage
 Vertical anchorage

 Transverse anchorage
1. TPAs can be used to improve arch
width stability when aligning palatally
impacted maxillary canine (Fleming,
Sharma et al. 2010)

Transverse anchorage
2) In cleft palate, TPA has its application
to maintain the form of the expanded
arch just before alveolar bone
grafting. (Harris and Reynolds 1991)
3) TPAs have been claimed to provide
horiantal anchorage of 1 mm per
yeer ( rot 1986 ) however there have
been doubts in this context and they
are no longer used for this purposes.

3. For almost the same application,
TPAs act as a retainer after RME
4. after surgical expansion of the palate
in order to hold the osteotomies part
together during healing period.
(Harris and Reynolds 1991).

TPA -Transverse anchorage
4. As an adjunct to headgear (HG),
TPAs are used to reduce buccal
tipping of the molar and palatal cusp
hanging the molar distalization.
(Baldini and Luder 1982) However, a
study by Wise et al. showed no
difference between the use of HG
with or without a TPA during molar
distalization

5) TPAs are used to counteract the
buccal tipping of the crown of the
molars during intrusion of the anterior
teeth using Segmented Burstone
Arch Wires mechanics. (Burstone
1966

TPA Transverse anchorage
5. Lastly, TPAs were used with palatally
or buccally placed TAD to control
molar tipping when posterior teeth
are intruded to treat anterior open
bites. (Cousley 2010)

TPA use an anchorage aid
1. It had been showed that placing the
TPA 4mm away from the palate
might introduce some intrusive effect
by the tongue on the molars which
can help in correcting or controlling
the over eruption of maxillary molars

 Vertical anchorage of upper molars by
placing the bar 5-6 mm away from
palatal mucosa with a large and
mesially facing loop is said by cetline
to prevent molars extrusion and
probably cause intrusion .

TPA use as an anchorage aid
 Anterior posterior anchorage
1. Nance appliance can be used to provide anchorage to
distalize the molars such as the Pendulum Appliance,
rapid molar distalization (REF); the distal jet, Jones
Jig and the Lokar Distalising Appliance .
2. In the same field, TPA can be used to maintain molar
position after distalization.(Prakash, Tandur et al.
2011) again TPA can be used to provide anchorage
during fixed appliance treatment through bringing the
roots of the upper molars in contact with cortical bone
(Cortical anchorage).
3. However, there are many studies that compare the
effectiveness of the TPA with other methods.,
McNamara concluded that the mean anchor loss of
4.1 mm was seen in association with the TPA and 4.5
mm in control group.

Ways to reinforce anchorage
5. Natural anchorage. Ankylosed teeth
possess no periodontal membrane and
as such are not subject to the normal
physiologic response to forces placed
on the tooth and movement will be
absolutely resisted.

Perscriptions and anchorage
1. Standard edgewise less anchorage
demanding.
Andres straight wire appliance comparing
to standard edgewise. Johnston et al (1988)
reported that the use of the SWA cost 0.8mm
more anchorage (measured by the Pitchfork
method) in the maxilla when compared with
Standard Edgewise treatment. However, this
may be explained by the fact that a preadjusted
appliance makes it less likely that a clinician
will finish a case with inadequately torqued
upper incisors, and the slightly higher
anchorage requirement with the SWA therefore
reflects the achievement of more anchorage
demanding occlusal goals.

2. Roth incisors are more OA
demanding
3. Andrews canines are less OA
demanding

4. MBT less OA demand than Roth and Andrews system
because:
i. The wagon wheel effect: because increasing the
incisor torque will cause the mesial tip of ULS to
reduce and this will reduce the anchorage demands
ii. Reduced canine, premolar and molar tip compared to
Roth
iii. Increased molar root torque buccally, increase
anchorage by cortical bone theory
iv. Reduce upper molar mesial tip reduced the OA
demand
v. Upper molar 10 degree offset, counteract the
unwanted rotational movement during space closure
in the upper arch and this might strengthen the
anchorage

5. Tip-Edge is less anchorage
demanding than SW because of the
relying on the tip-uprighting principle.

Measuring anchorage
1.Cephalometric using
 LLS position in relation to N-Pog or NB or MP
 This is probably the most common method in
clinical practice. A more labial position of the
lower incisors at the end of tooth movement
is conventionally considered to represent an
overall loss of posterior anchorage, although
of course such a change can be an entirely
deliberate treatment aim. Similarly, except in
the treatment of bimaxillary proclination or in
some class 3 cases, a more posterior
position of lower incisors following treatment
is considered to be unused intraoral posterior
anchorage.

Measuring anchorage –LLS
position
 Cephalometric measures such as Lower
incisor toNasion-Pogonion, or Lower incisor
inclination to mandibular plane are used to
assess this aspect of anchorage
consumption/loss. The reference structures
being used are theNasion-Pogonion plane or
the mandibular plane or - in the Steiner
analysis - the line Nasion-Bpoint. This is a
simple and very useful tool, but does have its
limitations. In particular, it gives no
information about the quantity and sources of
anchorage provided to move teeth distally,
only about the anchorage consumed.

Measuring anchorage
2. pitchfork analysis
 This is a very well known form of superimposition on
bony structures, described and popularised byLysle
Johnston (1985, 1996). This reference structure is
essentially the maxilla and zygoma. Johnston
developed a comprehensive set of measures relative to
a mean functional occlusal plane, which provide a
measure of anteroposterior movement of upper and
lower incisors and molars and the contributions of
mandibular and maxillary growth. Whilst still not
providing full quantification of the anchorage work done
(no measurement of changes in incisor inclination or
canine
 Superimposition technique of stable cranial structures

Measuring anchorage
3.Intraoral photograph
4.Study models by superimposing on the rugae area (Sandler 2014)
 Over many years, there have been investigations of the suitability of
the palatal rugae for superimposition of changes in maxillary teeth.
There has been a recent resurgence of interest in this method,
prompted by the developments in digital imaging which assist the
recording, enhancing and measuring of the upper study
models. Hoggan and Sadowsky (2001) reviewed some of the
previous papers and carried out a study which concluded that palatal
rugae landmarks are as reliable as cephalometric structures for
superimposition. However, it should be noted that the standard
deviation of repeated measurements was 0.8 mm or more for
several of the measures. This would mean that a real difference of
1.6 mm is unlikely to be shown to be statistically significant. Indeed
in the study, a difference of 1 mm between the cephalometric and
study model measurements of the same parameter was not
statistically significant. Of course, this also reflects on the relative
unreliability of cephalometric measures of molar position. Ashmore
et al (2002) have utilised different digitising techniques to measure
molar movement in the vertical and anteroposterior directions and
concluded that superimposition on the palatal rugae was sufficiently
reliable to pursue as a method.

 There is no ideal method of measuring
anchorage loss and anchorage
achieved, but cephalometrics provides
information of great value for both
scientific and clinical purposes. The use
of palatal rugae needs further
investigation, but with newer digital
techniques and the advantage of good
identification of tooth landmarks, it may
prove to have a useful place.
5.Direct Clinical assessment especially if
one arch is left as a base line

Monitering anchorage
 During treatment, the occlusion in centric relation
should be monitored:
◦ Overjet
◦ Molar relationship
◦ Canine relationship
◦ Residual space
 These measurements are used to assess how
treatment is progressing, and what anchorage
control measures are required

 Can be divided into anchorage control
methods during the first and second
phases of treatment.
 First phase: aligning and levelling
 Second phase: OB, OJ, space
closure
 Further subdivided into intra-oral and
extra-oral sources of anchorage

First phase – intra-oral
 Tube / bracket selection:
◦ MBT has less canine tip (8⁰) than Roth (13⁰) so is less
anchorage demanding
◦ MBT and Roth molars provide more anchorage than
Andrews
 Lacebacks – prevent mesial movement of
canine crowns as tip corrects (note RCTs –
Usmani et al 2002, Irvine et al 2004)
 Choice of extractions

First phase – intra-oral
(reinforcement)
 Palatal / lingual arches. TPA good at maintaining
arch width . Nance better for anchorage support
(shape of palatal vault is relevant). LLA, if used
for anchorage support, risks proclination of the
LLS
 Band 2nd molars if possible
 Anterior bite planes in deep bite cases – good
overbite reduction at virtually no cost to
anchorage
 CIII elastics at night, supported by headgear to
upper 6s, can be used in non-extraction cases,
or maximum lower arch anchorage cases.

Second phase – intra-oral
 Band selection: Roth and MBT provide
more posterior anchorage for OJ reduction.
 However, high torque in Roth & MBT incisors
are more demanding
 Constancy of archform.
 Selective application of torque (eg lingual
crown torque in LLS reduces anchorage
demand
 Choice of extractions (anchorage balance;
occlusal lock)

Second phase – intra-oral
(reinforcement)
 Band maxillary second molars.
 Intermaxillary elastics – class II or III
 Combination of class II elastics during
the day, and EOT at night can be used to
allow a 24-hour effect on the upper arch
while limiting the demand on lower arch
anchorage.
 Nance and lingual arches need to be
removed at this stage (standard TPAs
may be left in place for part of this
phase)

Second phase – extra-oral
 Headgear (Kloehn bow or J-hooks)
 J-hook headgear to lower arch for
retraction of lower canines and
incisors in Class III cases. NB Light
forces to avoid TMJ problems
 Facemask (DeLaire) for molar
protraction

Clinical scenarios
anchorage in 3 planes of space
 Lateral anchorage
 Anteriorposterior anchorage

Vertical anchorage
 Level the curve of spee
Both posteior extrusion and anterior
intrusion occure when levelling the
curve of spee , to increase anterior
intrusion for exmaple , banding of
second molars is advised to increase
the anchorage vlue of posterior
segment

Vertical anchorage
 Treatment of anterior open bite
The best example is utulized in the kim
mechanics , which relies on anterior box
elastics to counteract the effect of
reverse curve of spee wire to intrude
the molars
Can be considered a kind of
intermaxillary compound anchorage .

Lateral anchorage
 Horizantal anchorage in expansion
cases
Usually there is equivilant group of teeth
on both sides to expand , occasionally
both sides of the arch are assymetric in
number of teeth in crossbite , one
solution to this is to include a greater
number of teeth on the anchore unit
than in the unit in which maximum tooth
movement is needed.

Lateral anchorage
 Traction of palatally ectopic canine
This is highly anchorage demanding ,
usually traction is applied once the arch
form is stabilised by a heavy stanless
steel wire or two molars are stabilizd by
a transplatal arch

 However, in some situations loss of
anchorage can be used to advantage.
 for example, in a Class Ill malocclusion an
increase in overjet can be advantageous.
 Therefore anchorage requirements need to
be assessed at the time of treatment
planning.

References
 Contemporary orthodontics , william
R.Proffit , 5th edition.
 Bristol notes
 Excellence in orthodontics, David
Birnie , 2012.
 Fundementals of orthodontic
treatment mechanics , Bennet and
maclaughlin 2014 .
 British dental journal , Part 9:
Anchorage control and distal
movement ,D. Roberts-Harry1 and J.

Anchorage in orthodontics- Dr Lubna Abu Alrub

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