Anchorage preparation in pae /certified fixed orthodontic courses by Indian dental academy

Anchorage
preparation in
PAE
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

02/11/14


Topics of Discussion
Anchorage.
Classifications of anchorage
Types of anchorage
Anchorage for each stage followed in
Roth
Wick Alexander
MBT
Bioprogressive therapy
02/11/14


Introduction
Archemedes said, “ give me a lever long
enough, a place to stand and I shall lift the
earth.”
“ a place to stand”is what we are going to
talk about right now- simply put this is
anchorage.
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When ever a force is applied , the
stabilized site from where the force is
exerted is the anchorage.
For every force acting, there is an equal
force acting in opposite direction.The
undesirable actions must ideally be
negated or at least kept at bare minimum.
One effective way is to allow these
reactionary forces to be dissipated over a
large area. www.indiandentalacademy.com
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Anchorage refers to the nature & degree of
resistance to displacement offered by an
anatomic unit when used for the purpose of
effecting tooth movement. (Graber)
According to Profitt anchorage can be
defined as resistance to unwanted tooth
movement.
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Classification of
anchorage:
Maximum posterior anchorage
Reciprocal anchorage.
Maximum anterior anchorage.
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Simple
Stationary
Reciprocal
Intraoral
Extra oral
Intra maxillary
Inter maxillary
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Simple

Stationary
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Reinforced
anchorage

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Extra oral

Reciprocal
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Types of anchorage
Dynamic anchorage: generated by applying
moments or muscular forces. Moments can be
generated through cantilever springs or base
intrusion arches and applied to the anchor teeth.
These create distal tipping forced,which help to
resist anterior displacement of anchor unit Ex : tip
back mechanics, lip bumper.
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Reinforced anchorage: the
additional resistance to tooth
movement gained when several
teeth are joined together to act as
one large , multirooted tooth.
Prepared anchorage: anchorage
control accomplished by tipping the
teeth roots first, crowns second, to
offer increased resistance to the
later retraction of anterior teeth.
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Segmented mechanics:
Three-dimensional control during
retraction of the upper anterior teeth is
essential not only for facial esthetics, but
also for function of the stomatognathic
system and stability of orthodontic
treatment
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• A common orthodontic treatment goal
is to combine retraction with intrusion
and uprighting of the anterior teeth.
• To achieve this goal, clinicians often
bend the continuous archwire into a
shape that is expected to deliver
intrusive force.
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• Unfortunately, the many active and
reactive forces produced by a
continuous arch can combine to
produce extrusion of the posterior
teeth rather than intrusion of the
incisors.
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• Controlled distribution of forces between
the anterior and posterior parts of a fixed
appliance can only be accomplished by
dividing the arch into segments.
• Each segment is consolidated into a rigid
unit by a section of heavy rectangular wire,
with little or no play between wire and
bracket slot.
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• The anterior segment, usually including the
four incisors and possibly the canines,
forms the active unit, and the two posterior
segments, including the premolars and
molars, are the reactive units. When
necessary, the reactive units are connected
by a transpalatal bar to form a single rigid,
multirooted entity.
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• The planned displacement of the anterior
unit and the corresponding reaction of the
posterior units are carried out by
connecting the anterior and posterior units
with active elements, such as retraction
springs.

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• Clinically, the point of force application is
the bracket. If a pure force is directed
distally through the bracket, the tooth will
undergo a distal tipping movement— a
combination of distal translation and
rotation around the CR .
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• The rotation is the result of a moment of
the force (MF) produced because the force
is applied at a distance (d) from CR. This
moment is calculated as MF = F´d.
• If a pure translational movement of the
tooth is desired, the moment must be
neutralized. This can be done by
calibrating the retraction spring to produce
a couple at the canine bracket.
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3 piece base intrusion arch wire
• In non extraction cases in which flared
incisors are associated with intra – arch
spacing , full space closure is achieved
only when deep over bite is corrected.
• True intrusion is obtained by applying
single intrusive force through the C.R of
the anterior teeth.
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Base arch mechanism
• The base arch mechanism is made of
0.018x 0.025ss with helices . It can also be
fabricated from 0.017 x 0.025 tma with no
helices.
• It delivers 200 gm in the midline and 100
gm each side.

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T - loop
• The T – loop can be used for 3 types of
space closure
• Anterior retraction
• Symmetric space closure
• Posterior protraction.
• wire used is 0.017 x 0.025 TMA

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• T – loop is activated by 6mm for complete
space closure.
• Tooth movement occurs in 3 phases1.controlled tipping,
• 2. translation and
• 3.root uprighting.

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• Initial force system applies M/F ratio of
6 : 1 .this results in tipping.
• With 2mm of space closure M/F is 10:1
resulting in translation.
• Further space closure results in M/F ratio
of 12:1 .this results in root uprighting.

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Anchorage for each stage
followed in different systems

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Wick Alexander
lewis

Lang brackets are used for
canines & Lewis brackets are
used for lower incisors as well as
premolars.

lang
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Inter bracket distance
Increased inter bracket distance
increases flexibility of the wire hence
the forces applied are less.

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Mini-diamond brackets are
used in central & lateral
brackets.lateral bracket has a
hook attached to it for
engaging class II elastics.

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ular Initial arch wire
d ib
Man
a rc h
0.17 x 0.025 multi stranded D – Rect wire
is used as the first wire if torque control is
important & the mandibular arch is not too
crowded.
In case of moderate to severe crowding
0.16 x 0.022 D – Rect wire is used.

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0.0175 multi stranded respond wire is used
as initial wire in maxillary arch.
A round wire used in maxillary arch
especially in early treatment tends to
promote anterior dental advancement. This
is desirable in class II div 2 cases.
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Driftodontics :
The mandibular anterior teeth have a tendency
to drift distally. The mandibular posterior teeth
will drift mesially, but much more slowly.
Appliances are placed only on the maxillary
arch until a class I cuspid relation is achieved.
The late placement of mandibular appliance is
referred to as driftodontics.
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Individual canine retraction:
re

ns
aso

More control over molar anchorage
Cuspid is the largest rooted tooth in
the mouth, it is important to put it into
position as quickly as possible.
By retracting cuspids first incisor
retraction can be achieved with out
significant loss of torque.

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Anchorage conservation in
mandible:
Mandibular molar has – 6 degree tip
incorporated in it which promotes
leveling & helps in gaining arch
length (Tweed’s philosophy).
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Anchorage conservation
in maxilla:
Omega loops are bent into many
various vari – simplex discipline arch
wires mesially to the terminal molars.
Omega loop is generally the preferred
method of tying back.
Omega loops are placed in 0.016 ss
wires . In average case this is
supported with a face bow.

Om
e

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ga
l

oo
ps
:

An orthopedic effect occurs while the
cuspids are retracted & molars do not
advance.
If pt does not wear the face bow the
molar advances till the molar buccal tube
is in flush with the omega loops.
Any further mesial molar movement is
accompanied by maxillary incisor
advancement.
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retractor
Retractor is one of the most important
elements of varisimplex discipline.
It is the only appliance with which the
orthodontist can control all 3 dimensions –
vertical , sagittal & transverse both
skeletally & dentally.

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Advantage of face bow is that opposing
force is applied to the back of the neck or
top of the head.
Maxillary molar buccal tube is placed
either occlusally or gingivally.
Adv of gingival placement – tube is closer
to the C.Rot which reduces the molar
tipping effect.
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Advantage of occlusal
placement
Vari- simplex discipline includes the
use of omega loops in the posterior
segment. Omega loops can block
gingivally placed headgear tubes.
Pt finds it easy to insert the inner bow
into the tubes.
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Cleaning around the tubes is easier.

The retractor is usually placed 2 weeks after
the brackets are bonded & banded to the
maxillary arch.
When given initially light force is applied.
The neck strap is adjusted so that no more
than 8 ounces of force is transmitted through
the appliance.
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At the next appointment , 4 weeks later the
neck strap is tightened to produce a pull of
approx 16 ounces.
The elastic strap will fatigue over time. As
it stretches it has to be adjusted to preserve
a constant force.
Severity of class II pattern affects the
optimal amount of daily facebow wear.
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Pre treatment ANB is the ceph measurement
used to establish daily requirements.
If ANB is 3 or less , the pt will sleep with the
retractor but will not wear it when he is awake.
If ANB is 3 – 5 pt will wear it approx 10 hrs per
night.
If ANB is > 5 pt will wear the retractor 14 hrs
per day or more
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Incisor retraction:
0.018 x 0.025 ss closing loop arch
wire is used to retract the incisors.
Tear drop loops of approximately
5mm in height are used.
Before the wire is engaged the wire
distal to the cuspids is reduced to
approx 0.016 x 0.023.
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The closing loop is activated by about
1mm per month.

Roth :
The various factors which prevent
drifting of mandibular dentition
forward are facial type, amount of
over bite & occlusal forces.
Any orthodontic appliance forces that
tend to overcome these will result in
mesial migration of the dentition.
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Factors that cause posterior
tooth to move forward are
Attempting to upright extremely
distally tipped canines.
Pulling distally with posterior
teeth against extremely
procumbent or labially inclined
incisors.
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Attempting to level the curve of spee with a
continuous wire with out the use of distal
traction.
Attempting to do any of the first three tooth
movements utilizing either a stiff or a resilient
wire.
Attempting to move lingually or torque the
maxillary incisor roots.
Attempting to expand the mandibular arch with a
labial arch wire
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Stages
Leveling and aligning
Retraction
Finishing.
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Leveling & aligning
Start aligning with 0.015 wild cat
or 0.015 respond followed by
0.017 or 0.019 respond.
Anterior facebow is used to
upright lower anteriors.
Band the 2nd molars.
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Intrusion utility arch is
used to level the curve of
spee followed by a small
continuous wire.
Goshgarian TPA
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To widen a narrow mandibular arch, place
lingual arch with recurved finger springs to
widen the premolars prior to insertion of
labial arch wire.
To correct the cant of occlusion short class
II elastics 1/8 inch in diameter applying 48 oz of force www.indiandentalacademy.com
are used.

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Double key hole looped arch wire is
used for retraction.
Advantage – complete space closure
with single set of arch wires with out
coming back & changing the arch
wire.
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MBT
Anchorage control according to MBT:

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The maneuvers used to restrict
undesirable changes during the opening
phase of treatment , so that leveling &
aligning is achieved with out the key
features of malocclusion becoming
worse.

Horizontally AC is used to achieve a correct AP
position of teeth in the profile at the end of the
treatment.
Vertically AC is involves the need to try to
influence the vertical skeletal & dental
development in the posterior segments & at
times attempts to limit vertical eruption of
anterior segments or even intrude these.
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Laterally , AC involves the
maintenance of expansion
procedures , primarily in the
maxillary arch & the avoidance
of tipping and extrusion of
posterior teeth during any
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expansion phase.

Anchorage in horizontal plane
Control of anterior segments:
• Lacebacks ,bend backs
• Reduce the anchorage needs during
leveling & aligning.
• Bracket design – reduced tip.
• Arch wire forces – use of very light arch
wire forces.
• Avoidance of elastic chain
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Upper molar
Post anchorage control in upper arch is
more than the lower arch because
UM moves mesially more easily than the
lower molars.
Upper anterior teeth are bigger.
UA have more tip built into them
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UI require more torque control & bodily
movement than lower incisors which
require distal tipping or uprighting.
Most of cases are class II type of
malocclusion. Because of these factors
EO force is normally the most effective
method of posterior anchorage control
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Lower molars
Lingual arch – in the mixed
dentition cases it prevents the
lower molars from drifting
mesially.
Class III elastics
Head gear.
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Vertical control of incisors:
If the canines are distally tipped in the
starting, in such cases , as the arch
wire passes through the canine bracket
slot it will lay incisally to the incisor
bracket slot causing extrusion if the
wire is fully engaged.
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Vertical control of canines:
High labial canines should not be
engaged with arch wire because it
causes unwanted vertical movement
of lateral incisors and premolars.

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Vertical control of molars in
high angle cases:
Upper 2nd molars are generally
not initially banded , to minimize
extrusion of these teeth.
If upper molars require
expansion, an attempt is made to
achieve bodily movement rather
than tipping.
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Palatal bar should lie about 2mm away
from palate so that the tongue can exert
a vertical intrussive effect.
When head- gears are used in high –
angle cases either a combination pull or
a high pull headgear is used.cervical
pull headgear is avoided.
Upper or lower posterior bite planes in
molar region is helpful to minimize
extrusion of molars.

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Anchorage control in
lateral(coronal) plane:
Intercanine width: it should be kept as
close as possible to starting dimensions for
stability. Crowding is not relieved by
uncontrolled expansion of the upper &
lower arches.
Molar cross bites: molar cross bites should
be corrected by bodily movement of
molars. As far as possible tipping should
be avoided.
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Narrow maxillary arch:
If maxilla is too narrow, early rapid expansion
should be considered prior to leveling & aligning.
If adequate maxillary bone exists , a fixed quad
helix expander is used.
minimal molar cross bites are usually corrected by
using rectangular wires which are slightly
expanded from normal & which carry buccal root
torque.
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Bioprogressive therapy
Cortical bone anchorage:
The concept of cortical bone anchorage implies
that , to anchor a tooth , its roots are placed in
proximity to the dense cortical bone under a heavy
force that will further squeeze out the already
limited blood supply and thus anchor the tooth by
restricting the physiological activity in an area of
dense laminated bone.

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Three main aspects of tooth
movement & cortical bone
support:
Avoid cortical bone support where
ever possible & direct the roots
through the less dense & more
vascular trabecular bone. Light
forces are used.
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Anchor tooth by placing their roots adjacent to
the denser cortical bone .
When treatment objectives require that we move
teeth through the supporting cortical bone, where
the dense bone cannot be avoided but must be
remodeled,the forces must be kept even lighter
to respect the character of bone and its limited
blood supply & physiological response.
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Muscular anchorage
The facial type described by the
cephalometric morphology reflects the
musculature which supports the occlusion.
When the musculature is strong as
characterized by the deep bite, low
mandibular plane angle, brachy facial
type,the teeth demonstrate a natural
anchorage.
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In the open bite vertical
dolichofacial patterns, the
musculature seems weaker & less
able to over come the molar
extruding & bite opening effect
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of our treatment mechanics.

Upper molar anchorage
Maximum upper molar anchorage:
Nance plastic button followed by headgear.
Modification of nance lingual arch , with plastic
button against the rugae is the addition of a distal
loop on the mesial lingual of the upper molar
bands which allows the molar teeth to be
expanded & rotated.
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Nance plastic
button followed by
head gear

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Adv of expansion & rotation of
molars
Expansion places the molar roots out under the
zygomatic process where cortical bone support
resists change & thus anchors & limits their
movements.
The molars, placed in distal rotation, tend to resist
the forward mesial pull as the cuspids are being
retracted on sectional arch springs.
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For the final positioning in the
finishing occlusion . The finishing
alignment & details of occlusion
should be kept in mind even in the
first basic treatment movements.
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Moderate upper molar
anchorage:
Quad helix expansion arch.
palatal bar without plastic button support
will stabilize the molar & give moderate
anchorage support.
The lingual arch limits molar eruption &
vertical height development.
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Use of upper utility arch during cuspid
retraction with or with out the lingual
arch has a moderate anchorage effect to
the upper molars, since the intrusion
action to the upper incisors produces a
tip back to the upper molars, which acts
to stabilize them
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Quad helix

Upper utility arch
Sectional retraction then anterior
retraction

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Minimum upper molar
anchorage:
Class III extraction treatment usually calls for
upper second bicuspid extraction with
advancement of 1st molar.
Since upper molar has a natural tendency to rotate
& migrate mesially as it erupts, the advancement of
upper molar is a matter of encouraging &
supporting this natural process
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A vertical closing loop or double delta
loop will assist in its forward closure.
The forward migration of the upper
molar usually carries it into mesial
rotation & treatment mechanics will need
to compensate by uprighting with distal
rotations for a better final fit &
occlusion.
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Reciprocal
closing
mechanics

Protraction of
molar forward
after extraction
of 5’s.
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Lower molar anchorage:
Maximum molar anchorage: maintained through
the action of long lever arm of the lower utility
arch.
Buccal root torque that places roots against the
cortical support to limit their movement. Up to
45 degrees buccal root torque is placed in a 0.016
* 0.016 elgiloy wire.

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• Buccal expansion of the molar section of
10mm on each side is necessary to support
the buccal torque.
• Tip back of 30 – 40 degrees keeps the molar
upright & resists the forward pull in
response to the cuspid retraction springs.
• Distal molar rotation of 30 – 45 degrees is
placed in the molar section of the utility arch
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in extraction cases.

Moderate lower molar
anchorage:
Modifies the lower utility arch mechanics
to allow the molar to come forward during
cuspid &incisor retraction.
A contraction utility arch is stepped ahead
of the molar tube to advance the molar.
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Minimum anchorage mechanics:
To advance the lower molar forward the
four anchoring factors of torque, tip back,
expansion & rotation are minimized.
Round wire in the molar tube may be
used to eliminate the binding & torquing
to the molar & there by reduce the
anchorage. www.indiandentalacademy.com
02/11/14

Conclusion:
• In many cases , the successful
outcome of the treatment depends on
treatment planning.
• In PAE, anchorage should be planned
and taken care of from the first day of
treatment.
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For more details please visit

02/11/14


Anchorage preparation in pae /certified fixed orthodontic courses by Indian dental academy

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Anchorage preparation in pae /certified fixed orthodontic courses by Indian dental academy