Anchorage (5)

Anchorage
&
Its Management In
Stage I Of Begg
www.indiandentalacademy.com

Anchorage
 Webster “a secure hold sufficient to
resist a heavy pull”
 In orthodontics “nature and degree of
resistance to unwanted displacement
offered by an anatomic unit, when used
for purpose of effective tooth
movement”

Anchorage management
 Involves restricting movement of one
group of teeth while facilitating
movement of other teeth.
 Successful anchorage management is
key to successful orthodontic
treatment.

 “Anchorage preparation is most
important step in clinical orthodontics”
(Tweed)
 Begg light wire appliance develops its
total anchorage potential from with in
the mouth.

Relationship of tooth movement to
force
 Conc. the force needed to produce
tooth movement, where it is desired
 Dissipate the reaction force over as
many other teeth as possible keeping
the pressure in PDL of anchor teeth
as low as possible

 A threshold, below which pressure
would produce no reaction  perfect
anchorage control
 since it would only be necessary to be
certain that the threshold for tooth
movement was not reached for teeth
in anchorage unit.

 Amount of tooth movement α mag. Of
pressure ,up to a point.
 After this, AOTM is indep. Of
magnitude of pressure

 Optimum orthodontic force level for
movement is the lightest force &
resulting pressure that produces a
near maximum response
 Force > that ,equally effective but
would be unness. traumatic &
stressful to anchorage

Anchorage situations
 Reciprocal anchorage force applied
to teeth & to arch segments are
equal ,so the force distribution in
PDL

Anchorage value
 Anchorage value of any tooth 
roughly eq. to its root surface area
 5 & 6 in each arch is appro. eq. in
surface area to 1,2 & 3
Freeman’s
anchorage value
diagram

Reinforced anchorage
 By adding more resistance units.
 It is effective because with more
teeth (extraoral structures) in the
anchorage, reaction force distributed
over a larger PDL area.

Stationary anchorage
 Bodily movement of one group of
teeth against tipping of others

Anchorage bend
 In begg’s technique anchorage is
used
For retraction and intrusion
 Derived from single bend (anchorage
bend)

Anchorage bend
 Formerly called the tip-back bend.
 Bend whose vertex faces occlusally
 Placed in buccal segment at some point
mesial to the tube.

The manner in which anchorage is
obtained for vertical movements-
 When initial arch wire is inserted the
AB  ant. Portion should rest in
mucobuccal fold
 Engaged in brackets
wire will exert force on molar,
occlusal pressure on mesial end of tube and
gingival pressure on distal end

 This will tend to cause
Extrusion of mesial cusp & root
Intrusion of distal cusp & root
Distal tipping of crown
Mesial tipping of root

These tendencies encounter certain
resistance
Ex. Of mesial cusp opp. Occl. Force
Int. of distal cusp  bone
Distal tipping of crown 2nd
& 3rd
molars
Mesial tipping of root bone on mesial
surface
 Resistance not equal magnitude prevent
effect of anchorage bendwww.indiandentalacademy.com

 If arch wire viewed from side, mildly
gingival curve
reflect force for overbite correction 
resistance to movement exhibited by molar
 The amount of constant light force,
optimal for intruding the anterior
at a minimal level to produce movement
of molars. www.indiandentalacademy.com

The manner in which anchorage is
obtained for retraction
After arch wire attached
 class II elastic between I.M.H of upper arch
wire & hook on mesial end of lower molar
tube.
 Tend to pull molar forward & retract
anteriors

 AB counteract mesial pull
 If appro. Ab and elastics are used
(proper m/f) tooth lean upright,& if
move, bodily

 At the same time e retract ant. Ling.
by tipping
 The amount of force exerted by elastic
Optimal for tip the anterior backwards
At a minimal level to move of molars
forward bodily.

 Amount of force exerted by wire &
elastics is important if desired
movements are to be attained with
minimal anchorage loss, throughout
the Rx.

Orthodontic Judo
 Based on using the opponent’s greater
strength and weight to his disadvantage
 Enable a weak & small man to overcome
a large & strong man, based on scientific
principles of leverage and balance

The crown tipping tendency can be used to
advantage
↓
by simply eliminating the stabilizing
resistance supplied by wires and
elastics attached to other teeth
↓
crown takes the path of least resistance and
net result crown movement.

Attainment of beneficial crown tipping
movement resulting from root tipping
force or prevention of detrimental
crown movements by these forces is
called orthodontic judo

Three elements
 Lever arm( arch wire)
 Area of High resistance (bone around
roots)
 Area of low resistance (area around
crown)

 Under certain conditions, and relatively
early in Rx
 light forces can induce a backward
movement of anchor molar crown,
 which in themselves are being used to
move ant. teeth backward
 Contravention to Newton’s 3rd
law
 Like lifting yourself off the floor with your
own bootstrap
Operation boot strap: net distal movement
of anchor molars with judo mechanics

 AB tends to tip the molar roots
forward and crown backward
 Net effect of widespread difference
between the high resistance root
tipping and the low resistance crown
tipping
 More crown movement
AB force in first stage & net distal
movement of upper molars

 If molar mesially inclined at comm. of
Rx , net distal movement of crown to
upright position can be sig. for
class II correction
incr. arch length in nonext. Cases.

For net distal movement
 molar crown should freely move back
 No binding of arch wire in tube
 Do not bend the end of arch wire
 Do not use tie back ligature to molar
tube

AB force in first stage with or without
net distal movement of lower molars
 Lower molar crown also have tendency
to tip back
 Controlled by varying the force of class
II elastics
 11/2 – 21/2 ounce (nonext.) crown may
tip back more & root tip forward less

 21/2 – 31/2 ounce (ext.)
both crown & root may tip, uprighting
the tooth but imparting little or no
distal tipping
 Net distal movement is proportional
to amount of elastic force

The location and degree of
angulations of A.B, depends upon
 Types of arch wires
 Location of extraction space, if any
 Depth of overbite
 Hazard of occlusal impingement and
distortion aids
 Inclination of anchor molars

Variations in the angulations of AB
Stage of treatment
 In stage 1- usually greater than
stage 2 except for open bites
 Little if required in stage 3.

Depth of overbite
 In avg. deep bite cases –
anterior segment of wire rest
passively at the depth of mucolabial fold
 In open bite case-
to keep the anchor molar of both
jaws upright against the mesial pull of
elastic and wire. After OB correction
↓ to prevent dev. excessive OB or distal
tipping of molars.

Rate of progress of case
 If progress is unsatisfactory, bend or↑
relocate bend closer to molar tube.
Inclination of anchor molar at the
commencement of the treatment
 If molars are inclined mesially ↓ AB, so
that wire rests passively in mucolabial
fold.

 On severe mesial inclination-
No AB initially
Later for uprighting molar
 unilaterally mesial inclined molar
the increased intrusive force on that
side can be prevented by using vertical
elastics and arch wires.

Variation in location of AB
Stage 1 of treatment
placed forward to the molar tooth to
permit it to slide back to tube during
space closer
but not to enter the tube

At the commencement of treatment
distal to premolar or tip of buccal cusp
Mild overbite/open bite cases
formed as gentle curve located at the
head of bicuspid bracket

Nearer to molar tube
 Occlusal impingement
 Difficulty and delay in overbite
correction
 non extraction case
 In first molar extraction cases
 In second bicuspid extraction cases

 When progress rapid
placed farther forward
 If little space remains
placed far enough forward to
assure that old teeth will come into
proximal contact before AB reach the
molar tube.
The rate of progress and amount of
space remaining

Location of AB in loop arch
wires
 used for 2-3 appointments
placed far enough forward to
assure that it will not slide back and
reach the molar tube.

Causes of loss
of Anchorage in stage I
and
its preventionwww.indiandentalacademy.com

Vertical loop touching the labial
surface of the teeth
 A loop resting but not touching labial
surface of ant. teeth
 As the crown tip lingually  loop is moved
towards the teeth  inhibit further free
tipping of ant. Teeth in same arch, may
affect opp. Arch also.

Prevention
 Proper arch wire fabrication
 Proper location of loops &
limitation of the number of loops
 Slightly labial inclination of loops
in severe crowding cases

Vertical loop impinging on the
gingival tissue
 Prevent free tipping but less than if
touching the tooth
 If impinge on gingiva become imbedded
by next visit
 Prolong first stage I

Prevention
 Care modification of loops
 Slightly labial inclination of loops when arch
first applied
 Do not modify the loop without removing
from mouth

Intermaxillary hooks not cranked
out
 Vertical portion of I.M.H resting snugly
against the canine  +ve braking
mechanism
Prevention
 I.M.H should be cranked out before arch
wire is applied
 Use horizontal circle

Distal leg of I.M.H sliding against the
lock pin & becoming engaged in canine
bracket
 Prevents free and simple tipping of canine
crown
 Usually happen when loop arch wire are used
to unravel ant. Crowding

Prevention
 I.M.H should be cranked far enough
labillay, engage against the mesial
surface of bracket

Elastic over the I.M.H engaging the
labial surface of canine
 Not major cause
 Due to using thick elastics or two
elastics
Prevention
 Modify I.M.H so that elastic not
produce undesirable pressure

Lock pin binding the arch wire
in the bracket
 If one or more ant. teeth are bind
Prevention
 Use special safety lock pins
 If conv. Pins, tails should be bend
before head strike the arch wire

Cuspid forced out into buccal plate
 Improper arch wire form
 Causes drag teeth can not tip freely

Prevention
 Place the distal ends of arch wire in
molar tubes, see if wire lies so far
labially in canine region

Too strong elastic force
 Use proper intermaxillary elastic
force
 2-21/2 ounce
 Molar will come forward

Wearing more than one elastic
Pt. must be properly educated in
 function of elastics
 Danger of wearing more elastics

Elastics not worn continuously
 Intermittent wearing causes anchor tooth
to become loose
 Ant. Teeth hardly move
 Prolong Rx  anchorage loss
Prevention
 Proper patient education

Arch wire accidentally engaged in
the slot of second premolar
 Increases friction
 In mes.ling molar rotation wire may
acci. engage
Prevention
 Use of bypass clamp
 Remove the premolar band for first 6
weeks

Arch wire binding in buccal tube
 If arch wire too short to protrude through the
distal end of molar tube
 When cut to proper length, cause internal
burring (not removed by ordinary polishing)
Prevention
 Make always slightly longer than necessary
 Do not cut the end of wire until all
modifications and bends, 1/8”should
protrude

End of arch wires striking the
second permanent molar
 Retards and sometimes stops the
distal sliding of arch wire (usually in
upper molar)

Prevention
 Extend the arch wire farther distally
through the 1 molar tube not only to
prevent striking but also to move 2nd
molar lingually
 If impossible, cut it short enough to
allow it to slide freely until next visit

End of arch wire penetrating the
gingival tissue
 Usually distal end of lower arch
 Gingival tissue (bone) prevent free
sliding
Prevention
 Patients should be instructed to visit
orthodontist if they feel discomfort or
Can not engage elastics

Anchorage bends engaging buccal
tube
 Once entered in molar tube free
sliding is prevented due to three point
contact
Prevention
 Check the situation every visit
 If necessary remove the
arch wire, st. it and, make
new anchor bend mesially

Ligating premolar too tightly to
arch wire
 Arch wire can not slide distally
Prevention
 Ligate the arch wire lightly so that arch
is free to slide

Insufficient anchorage bend in first
arch wire when first applied
 Good rule to follow to incorporate
enough AB to cause the ant. section to
lie against the floor of mucobuccal fold
when distal ends of arch wire is
threaded into molar tubes.

Prevention
Not to estimate the amount of bend in
number of degrees, because
 Inclination of molar and buccal tube
 Length of arch wire
must be taken into account

Distorted anchorage bend
 Seen in negligent pt. mesial to lower
molar tube, esp. when lower 2nd
premolars are not present
Prevention
 Examine the arch wire closely
 If distorted ,remove from mouth,
eliminate the distortion

Too much anchorage bend
 May cause distortion of arch wire
 May cause arch wire to rotate in molar
tubes rotate the molars  failing to
depress molars

Improper toe in
 Results in loss of control of anchor teeth &
failure to reduce ant. Deep bite.
 Proper amount of toe in or toe out is
determined by placing the arch wire in molar
tubes & in anterior brackets
 The wire should pass st. forward and occlusally
as it leaves the tube from the action of
anchorage bend.

Arch wire too soft
 Arch wire material must have higher
resiliency that is compatible with
freedom from likelihood of # of arch
wire while they are being worn
 Other wise Rx time will increase 
more anchorage loss

Overactivated expansion loops or
improperly bent arch wires
 Cause rapid initial labial tipping and
spacing of ant. Teeth
 More force time spend to recover
original lab.ling.
inclination of ant. Teeth
 Loss of anchorage

Bend – over free end of lock pin
impinging on arch wire
 A lock pin tail striking the wire distal to
caninedoes more harm than the same
in C.I
Prevention
 Use short lock pin or cut the lock pin
tail off flush with the side of bracket
 Bend all pins tail to mesial.

Wrong type of bracket
 Do not edge wise bracket
 May allow ample tipping labiolingually
but it restricts mesiodistal tipping and
causes loss of anchorage

Arch wire rolling in buccal tube
 Avoid too much anchorage bend
and/or too much toe in bend

Improper arch wire form
 Arch wire should keep all teeth in the
cancellous through of alveolar bone
 Arch wire must be bilaterally similar
in form or should be so shaped as to
eliminate any asymmetry of arch

Upper and lower arch wire forms
not coordinated
 Teeth will assume faulty relationship
 Ant. or pos. cross bite  cuspal
interference  prolonged Rx time

Internal diameter of buccal tube
too small or large
 Best internal diameter 0.036” for 0.016”
wire
 if less free sliding will reduced
 if more  molar control lessen,
depression force on ant. Lessen

length
 Length 0.20” – 0.25” ,
 shorter tube  lessens molar control &
force of anchor bend,
 longer tube  more control, reduces the
distance of arch wire between mesial
end of molar tube and premolar bracket
operational difficulties during stage 3.

Retaining looped arch wire longer
than necessary
 Danger of loops moving into such
positions that they press against
labial surface of ant. teeth
 Not transmit tooth depressing force
as accurately as an arch wire without
loop
 Cuspid will depress more than
incisors

Binding of doubled-back arch wire
in flat oval tube
 Binding will occur by having the legs too
far apart
 May be due to too large a radius where
the arch wire returned on itself, or too
long a vertical section extending from the
hook that is wound around the arch.
 Legs of double back are not ll.

Curving arch wires between
expansion loops
 Make the arch wire st. between the loops
 If need to modify the form make bends in
the loops
 When engaged, loops become distorted 
rotations of the sections of archwire
 If curved three point contact  inhibit free
lab.ling. tipping

Thumb or finger sucking, lip sucking,tongue
thrusting and abnormal sleeping habits
 Retard or prevent treatment progress
 Cause loss of anchorage
Prevention
 Habit breaking measures

Improper ligature tie at canine
 do not pass ligature ties on canines
over the incisal of brackets 
prevents free tipping
 It should pass directly
distally across the labial
surface of canine

Anchorage bend too far mesially
 Ideal location at the mesial of anchor molar
 It may become restricted by ligature tie on
bicuspid, preventing free distal sliding
 Arch wire will be projected
towards the occlusal plane
and be deformed by occlusal
forces.

prevention
 Anchorage curves instead of bends
 Gently curved anchor bend can be
initially placed so far mesially in the arch
wire that it is unnecessary to remove the
arch wire from mouth in order to make a
new bend farther.

Using 0.014” instead of0.016” wire
 0.014” exerts insufficient force from
its anchorage bend to prevent the
anchor molars from being tipped
mesially.
 Ant. Deep bite will also not open

Loosening of anchor molar bend
 Pull the affected molar forward
 Anterior teeth are not depressed

Conclusion
 Place adequate anchorage bends in
both arch mesial to molar tubes
 Use of arch wires, rubber elastics
which exert tooth moving forces of
low value.
 Not to move any teeth bodily other
than anchor molars in stage I

Anchorage (5)

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