Canine retraction /certified fixed orthodontic courses by Indian dental academy

ON
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INDIAN DENTAL ACADEMY
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INTRODUCTION
There are numerous methods of retracting the canine
teeth with fixed appliances.
Fixed appliances are necessary to treat malocclusion
which require some bodily movement or rotation of the teeth
to produce and aesthetic, functional and near ideal occlusion
as is possible. However, bodily movement takes longer and
is more difficult to achieve than moving teeth by tipping.
Thus over the year many different fixed appliance
techniques have evolved in an effect to produce bodily
movement as speedly as possible with maximum anchorage
control. www.indiandentalacademy.com

HISTORICAL PERSPECTIVE
Canine retraction by removable appliances was done
as early as the late 19th
century various kinds of springs were
developed for simple pushing back of canine teeth.
More popular are :
Finger spring
Helical canine retractor
U-Loop canine retractor
Buccal canine retractor
Palatal canine retractor
Robert’s Retractor
However, all these springs caused uncontrolled
tipping and extrusion of the teeth since control of tooth
movement in three dimensions is lost, canine retraction by
removable appliance is not preferred in modern orthodontics.www.indiandentalacademy.com

ANGLE’S METHOD
Though Angle normally did not advocate extractions
with subsequent canine retraction when it was required the
usual course of treatment was to level both the arches and
engage the canine with ligation tie backs of the arch for space
closure. Often this resulted in even more than one half the
loss of the space at the extraction site.
TWEED’S METHOD
One of the early methods that Tweed purposed to
place push coil springs along the continuous 0.016 round arch
and push the cuspids from one cuspid to the other
meanwhile tying back the arch to the molars which were
employed as anchors. This was not always satisfactory,
however, as the molar teeth still appeared to come forward
despite the reciprocal force operating against the canine from
side to side. www.indiandentalacademy.com

Dr. HARRY BULL
Another was the technique advocated by Dr. Harry
Bull, A squashed vertical loop with an 0.0215 x 0.025
edgewise wire was opened the distance of a “Thin dime” as
tipping followed by uprighting was done is a series of
adjustments of arches by either sections or complete arches.
Another development was the technique of using
sliding hooks on the arch to retract the cuspids along a
continuous arch. Pull coil spring to slide the hooks were
common methods. Rubber band elastic traction also became
common, as canine teeth were moved along the continuous
arch various methods with the edgewise technique.

RICKETTS
In 1950, started sectioning the upper arch and used
push coil springs for canine retraction. He refined his
methods and after experimenting on numerous loops, helics
and wires, introduced the Rickett’s retractor in 1979.
BURSTONE
After the TMA wire introduced Charles. J. Burstone
introduced the Burstone T loops for sectional cuspid
retraction in 1984 and refined it in 1994.
PAUL GJESSING’S
He introduced the PG canine retraction spring in 1984
and refined it in 1995. www.indiandentalacademy.com

Canine retraction mechanism can be generally classified
into 2 types
Group A : Sliding the canine tooth along the arch wire
(Friction)
Group B : Distal movement of the canine with the arch wire
(Frictionless)
GROUP A : Sliding the canine along the arch wire :
Advantages
Minimal wire bending time.
No running out of space for activation.
Patient comfort
Less time consumption for placementwww.indiandentalacademy.com

Disadvantages
Confusion regarding to ideal force levels?
Tendency to over activate elastic and spring forces. This
causes initial tipping and then inadequate rebound time of
uprighting if the forces are activated frequently.
Generally slower than loop mechanics due to presence of
friction.
Mechanics involved

To move a tooth bodily the force applied has to pass
through the centre of resistance of the tooth.
However as the force is applied as the bracket level of the
crown, the concerned tooth experience both force and
moment.
The moment of force is created in 2 planes of space.
- One moment tends to rotate the canine mesial out as
force application is buccal to the centre of resistance.
- Second moment tends to cause distal tipping of tooth as
the point of force appliance is occlusal to centre of
resistance.
The wire bracket interaction tends to counteract this
moment by applying on opposite moment.

As distal tipping of the crown takes place, the tooth
slides along the arch wire till bending occur between the
arch wire and the bracket. This produces a couple at the
bracket which results in distal root movement and hence
uprighting of the tooth.
As the tooth uprights the moment decreases until the
wire no longer binds. Then the canine retracts along the
arch wire till distal crown tipping again causes binding.
This process is repeated until the tooth is retracted or the
force gets depleted.
The magnitude of the root uprighting depends on the
size, shape and material of the wire and the width of the
bracket. The larger the load deflection rate of the wire, the
greater the force from its deflection and hence greater the
moment produced.
- The wider the bracket, the larger is the moment arm and
hence greater is the moment.www.indiandentalacademy.com

Methods
Elastic thread.
Elastic bands hooked over prefabrication ligature hook.
Elastic module with ligature (Benett’s method)
Elastomeric chains
Coil springs
J Hook Head Gear
Sliding jig and traction.
Mulligan’s V Bend sliding mechanics.
Employing tip edge brackets on canines.

Elastic thread
Elastic thread is inserted under the arch wire in a figure
of 8 configuration from the canine to premolar and firmly
knotted.
The premolar is firmly / tightly ligated to the molar by
a stainless steel ligature wire.
Elastic thread is obtainable in two different forms
- Cotton covered
- Plain uncovered elastic the sizes available are
0.625mm (0.025”) and 0.75mm (0.030”).
The cotton covered elastics is easier to knot firmly but
becomes dirty in use.
The uncovered elastic remains clean in mouth but with
passage of time can loosen.www.indiandentalacademy.com

Advantages
Neat method.
More comfortable.
Bodily movement of the canine tooth is achieved.
Easier to replace inorder to reactivate at each visit
without removing the arch wire.
Disadvantages
Thread is wasted in tying the Knot.
The knot will untie unless it is pulled very tight.
Knot causes irritations to the cheek if it is not carefully
tucked out of the way.
Difficult to regulate the forces.
This technique not recommended for use when the
canine can be engaged only by a thin arch wire.

Intra or Intermaxillary elaster to Kobayashi ligature

The Kobayashi ligatures are SS ligatures incorporating a
welded hook for inter or intramaxillary elastics.
They are loosely tied to the canine bracket and can be
left as a hook pointing mesially or can be tied so that the
hook faces distally and is then bent forward.
It is a useful method of applying light forces to tip the
canine distally along a thin flexible arch wire.
It is not a good method of applying traction to an
already upright canine which requires further retraction
by bodily movement.

Advantages
Simple to put on.
Readily measurable constant light force to tip the canine
along the arch wire, in the range of 40 – 100gms.
Can be applied by the patient hooking the elastic bands
over the ligatures.
Disadvantages
Not an effective method of applying traction to slide the
canine bodily along the arch wire because the strong
elastics required for bodily movement cause rotation and
excessive bending of the canine.
Relies on patients compliance in wearing elastics and
wearing them correctly.www.indiandentalacademy.com

Elastic module with ligature
This method popularized by Benett and McLaughlin.
A single elastic module of the type used to secure arch
wires to brackets is attached to the canine by ligature wire
extending from the molar.
These elastic tie backs are activated 2-3mm or to twice
then original size to generate approximately 100 – 150 gms
of force.
If the arches are properly levelled this light force allows
for effective retraction with minimal tipping of teeth and
maintenance of arch levelling.
Benett recommended 0.019 x 0.025” rectangular wire in
0.022” slot to be most effective, providing maximum
rigidity while allowing adequate freedom for sliding.www.indiandentalacademy.com

Retraction rate of 1mm/month.
Alternate delivery systems have been found to be
disadvantageous to elastic module in the following aspects.
a. Power chains – gives variable force
- difficult to keep clean
- may falls off
b. Elastics - Require patient compliance.
c. SS coil springs - Deliver excess force and
- Unhygienic
Elastomeric chains
Introduced into the dental profession in 1960’s and
are used in orthodontic practice for canine retraction,
diastema closure, rotation correction and arch construction.
Advantages
Inexpensive
Relatively hygienic
Easily applied without arch wire removal.
Not dependent on patients cooperation.www.indiandentalacademy.com

Disadvantages
When extended and exposed to the oral environment
they absorb water and saliva.
Permanent staining occurs after a few days in the oral
cavity.
Stretching causes breakdown of internal bonds leading
to permanent deformation.
Stress relocation lead to loss of force and hence gradual
loss of effectiveness.
Loss of force with time leads to variable levels of force
during the time the power chain is active in the mouth.
This results in decreased effectiveness.
Difficult to clean.
Can untie or break if not placed with care.www.indiandentalacademy.com

Tooth movement, pH and temperature changes,
fluoride rinses, salivary enzymes and masticatory forces
have all been associated with deformation, force
degradation and relaxation behaviour or elastomeric
chains.
Most of the elastomeric chains generaly lose 50 –
70% of their initial force during the first day of load
application and at the end of 3 weeks retain only 30 – 40%
of their original force.
To overcome the problem of rapid force decay rate
and provide for a more constant and consistent force
delivery, prestretching of E chain has been suggested. But
with this the increase in residual force at 3 weeks is only
5% coupled with a 50 – 75% reduction in the initial force
after prestretching.

Types
E chain are available in 3 configuration
Closed loop chain
Short filament chain
Long filament chain
Long filament chains generally deliver a lower initial
force and exhibit a greater rate of force decay at the same
extension.
Clinical consideration when using E chain
The M/F ratio is at its lowest at the initial placement of
modules or power chain as the force level in highest.
- This leads to distal crown tipping of the canine.
As the tooth is retracted, the M/F ratio increases and
force decreased, a moment is produced due to arch wire
binding in bracket thus uprighting the root (Walking
canine phenomenon).www.indiandentalacademy.com

To optimize tooth movement sufficient time should be
allowed for the distal root movement to occur.
A common mistake is to change the E chain or module
too often thus maintaining high force levels and a M/F
ratio that produces distal crown tipping only.
Constantly high force can cause excessive hyalinization
of periodontal ligament and inhibit direct resorption
around the canine.
Therefore, E-chain should be changed at an internal
of 4 – 6 weeks to optimize sliding retraction of the canine.
Closed coil spring
Coil springs were introduced in orthodontic as early as
1931.
The various materials that have been used for making
springs are
- Stainless steel
- Niti
- Co – Cr - Ni Alloy

Advantages of NiTi Coil springs
Shape memory and super elasticity.
Low modules of elasticity, moderately high strength,
high resilience and low corrosion.
Deliver constant amount of form till they reach the
terminal end of deactivation stage.
Produce constant force over a wide range of activation
and generally close space with single activation.
Can be easily placed and removed without arch wire
removal.
Do not need to be reactivated at each appointment.
A cooperation not required.
Disadvantages of NiTi springs
Relatively unhygienic compared to elastic force systems.

Different ways of using coil springs
Coil springs threaded on to the arch wire and
compressed between the canine brackets.
Coil spring compressed between a soldered stop on the
arch wire and canine bracket.
Compressed between an incisor bracket and the canine.
Compressed by a tie back ligature.
Expanded tied back coil spring.
Coil spring compressed between canine brackets
Coil spring measured 3/4th
of distance canine pulled
twice its length and compressed.
The arch wire should closely fit the bracket slot, and
cinches distal to molar.www.indiandentalacademy.com

Advantages
Force applied is easily measured.
The long length of coil will transmit a relatively constant
force over a long distance.
Requires little reactivation.
Disadvantages
Increase in intercanine width as the coil spring on the
anterior curvature of the arch wire exerts a lateral as well as
distal component of force.
Length of coil spring can be irritating to the patients lip.

Coil spring between soldered stop and canine bracket
Small piece of wire soldered on either side to act as stop.
Generally placed at distal margin of lateral incisor.
Two length of closed coil springs, a little more than half
of the distance of stop and canine are selected and then
compressed.
The arch wire should closely fill the slot.
Advantages
Less irritating to the patient than long continuous coil.
Neat
Forces applied are easily measured.
Disadvantages
Annealing of the wire during soldering.
Increase in intercanine width may occur.
Spring required reactivation more frequently.
To reactivate a compressed coil spring 2mm length of
close spring are used to recompress it.www.indiandentalacademy.com

Coil spring between incisor bracket and canine tooth
Coil spring is compressed between central incisor and
canine bracket.
Excellent method of closing upper incisor spaces /
central diastema, using the force exerted by the reciprocal
action of the coil spring.
Coil springs compressed by a tie back ligature
Two 3 – 4mm length of closed coil spring opened to twice
their length then recompressed are threaded to the arch
wire to lie mesial to the canines.
Using soft SS ligature is placed mesial to springs twisted
and tied to premolars.
Arch wire should be rigid and should fill the slot.

Advantages
Coil spring short and less irritating.
Easily activated by retying or tightening the tie back
ligature.
Disadvantages
Long ligature likely to be damaged.
Tied back expanded coil spring
This technique uses a coil spring is opened on activating
pulling the canine distally rather than pushing it as the
compressed spring does.
Can be used to tilt back a mesially inclined canine along
a thin flexible arch wire or can be used to bodily retract the
causes sliding it along a right arch wire.www.indiandentalacademy.com

Advantages
Coil spring can be removed any time without removing
the arch wire.
Forces can be measured.
Spring activated by simply tightening the ligature.
Intercanine width is not increased as coils lies behind the
canine.
Disadvantages
Susceptible to damage.
Ligature can fracture.
Spring tends to act as food trap.
Extra oral Traction
The arms of the extra oral traction are bent into a small
open circle (J hook) and hooked directly on to the arch wire
to contact mesial of the canine bracket.

The direction of the pull should be as near as possible
along the occlusal plane, this usually requires a straight
pull headgear for both maxillary and mandibular canine.
However, when this technique is used to retract all four
canines together a high pull head gear is used for the
maxillary canine and a straight pull for the mandibular
canine.
Advantages
Extremely conservative of anchorage.
Additional molar support by headgear may be done.
Sympathetic overjet reduction might occur during
canine retraction due to the distal force and binding of the
archwire.
Can be applied to both upper and lower arches
simultaneously (use of Hickham’s headgear system)www.indiandentalacademy.com

Disadvantages
As force application is intermittent this is slower than
other method of canine retraction.
Highly dependent on patients cooperation.
Canine tipping and anterior extrusion may occur with
straight pull headgear.
Soreness of the corner of mouth from side piece arm can
occur.
The molar and buccal segment correction is usually a
later event in treatment compared to other system.
Mesio buccal rotation of canine.
Flaring of canine into buccal cortex.
One canine may retract faster than the other (this may
be due to patient hooking the traction arm on to the same
side first).

Sliding jig and traction
In this a jig is made in 0.022” round wire of 0.017 x
0.022” rectangular wire and slide on to the arch wire is
addition to a short piece of open coil spring of about 4mm
in length.
The coil spring lies in contact with mesial end of canine
bracket and circle of jig lies on the mesial end of coil spring.
The traction can be applied to the jig by either intra or
inter maxillary elastics or by extra oral traction.
Advantages
Force exerted by the elastics is directed along the arch
wire and thus bodily movement of canine is possible.
In cases of extraoral traction method, the jig brings
forward the point of application of J hooks thus reducing
the soreness at corner of mouth.

Disadvantages
Difficult to fabricate
Food entrapment
Can dislodge the brackets
Irritation to cheek.
Mulligan’s V Bend sliding mechanics
Introduced by Mulligan in 1970’s.
The basic principle was to apply differential moments to
the teeth via bends in the continuous arch wire while force
for retraction was applied by auxillaries like E chain, coil
spring etc.
In 0.018” slot 0.016 SS
0.022” slot 0.016 , 0.018, 0.020 used for retraction.
The arch wire is not tied in the incisor bracket during
cuspid retraction, as this reduces
a. Distal root moment placed in cause
b. Causes incisors flaring
c. Causes severe mesial root movement of canine.www.indiandentalacademy.com

The wire is tied in 4 – 6 weeks for alignment then 45° V
Bend are added and 200gms of force is applied between
canine and molar.
The purpose of V Bend is to allow differential mesio distal
moments on canine and molars.
- If the bend is off centered it creates a short and long
segment.
The short segment is more rigid and hence applied
greater moment, so if maximal canine retraction is required
the bend is placed close to molars and bicuspids not banded.
- This causes strong distal crown moment on molar which
counteracts the auxiliary force tending to move molar crown
forward – Reinforcing anchorage.www.indiandentalacademy.com

The long segment is towards canines, applies a moment
to keep canine upright, allows some tipping to occur as
moment is less. Thus canine gets retracted by tipping and
uprighting.
As canine retracts the bend becomes less offcentered and
mesial crown uprighting moment on canine increase.
Use of tip edge brackets on canines
Tip edge brackets used in cases of an upright or distally
tipped canine as the arch wire insertion can causes bite
deepening due to incisor extrusion.
This eliminates binding between wire and slot during
initial stages when major movements are accomplished.
As retraction is complete uprighting springs may be used
to correct canine angulation without causing anterior
extrusion. Full size rectangular wire can be then placed for
achieve desired tip / torque specifications.www.indiandentalacademy.com

GROUP – B :
Distal movement of the canine with the arch wire
(Frictionless Mechanics)
Bio Mechanics :
When a retraction spring in used, two moments control
vertical and an anchorage forces. The α moment produces
distal of an of anterior teeth while the β moment causes
mesial root movement of the posterior teeth by varying the
magnitude of these moments differential movement of
posterior and anterior segment can be achieved.
However if α and β moments are unequal vertical forces
are also generated.
a. If β moment > α moment
↓
- Posterior anchorage in enhanced by mesial root
movement of posterior.
↓
- Net intrusive force on anterior teeth

A
B
C
PG Universal Retraction Spring can be adjusted for canine retraction
(A), uprighting of canine (B) or incisor Retraction (C)

Center of resistance (CR) is point through which
application of pure force will produce translatory
tooth movement
Pure horizontal force directed
through canine bracket results in
combination of translation and
rotation around CR.
Antitip and antirotation moment
-to-force ratios required to produce
translation of canine assuming
conical root of average dimensions

b. If α moment > β moment
↓
Anchorage of anterior segment enhanced by distal
root movement of anterior.
↓
Net extrusive force an anterior segment.
c. If α = β moment, no vertical forces are generated
The distance that the anterior and posterior segment are
to be moved depends on factor such as
- Amount of crowding
- Anchorage
- Axial inclination of canines an incisors.
- Midline discrepancy any and right / left symmetry.
- Vertical dimensionwww.indiandentalacademy.com

The amount of anterior retraction or posterior protraction
needed should be determined before a loop is designed.
a. For anterior retraction
- Loop placed closer to canine than molar
↓
- Gable bend added near the molar
↓
- Gable bend larger in posterior dimension
produce a large β moment and thus increases
posterior anchorage.
b. For posterior protraction –
- Loop located closer to the posterior segment.
↓
- Anterior Gable bend placed.
↓
- Gable Bend has large α moment than β thus
making anterior segment as anchorage.

c. For both anterior retraction and posterior
protraction loop placed midway between anterior
and posterior segment.
↓
Gable bend at equal dimension used
↓
Equal α and β moment generated
↓
Reciprocal space closure occur
Regardless of the initial magnitudes of both α and β
moment, changes will occur during retraction.

a. As anterior teeth are retracted the magnitude of α
moment decreases faster than β.
↓
- Enhancing posterior anchorage. Also as β moment
becomes relatively greater.
↓
- Greater intrusive force on anterior teeth and
greater extrusive force on posterior teeth.
b. Concurrent with the decrease in both α and β
moment there is increase in M/F ratio thus
producing a pure translation.
Note : Since M/F ratio, increases as the spring
deactivate, the spring should not be reactivated too
often. Frequent reactivation will not allow the spring
to achieve a high enough M/F ratio to produce
translation. www.indiandentalacademy.com

Optimal force Level :
- According to Smith and Storey 150 – 200 gms
- Reitan 250gms
- According to Lee 150- 200 gms
- Ricketts and Association 75gms.
Moment to force Relationship
A pure horizontal force acting at the bracket results in
tipping (translation or rotation) of the tooth where an
translation is obtained by adding a couple at the bracket so
that the ratio between moment and horizontal forces (M/F)
equals the distance from bracket to center of resistance. The
bracket is on an average 4mm from edge of cusp. This
implies that an average M/F ratio of 11:1 in required to
prevent tipping of the canine. The couple required is the anti
tip couple the antirotation couple acts in a horizontal plane
to counteract rotation which takes place when a pure
translation force is directed through the bracket. The
anterior rotation M/F in estimated at 4:1 which equal the
distance from bracket to tooth arm.

Constancy of Force and Moments
Optimal biologic responses not only, depends on the
initial force magnitude but also on the rate of decay of force
taking place between activation.
According to Burstone the M/F ratio can be increased by
Increasing vertical dimension gingival to the bracket.
Increasing the horizontal dimension in the apical part of
the loop.
Decreasing the inter bracket distance.
Positioning the loop close to the tooth to be retracted.
Angulating the mesial and distal legs of the spring
Adding more wire gingival to the bracket.www.indiandentalacademy.com

What is an ideal canine retraction spring ?
One which
Promotes translation sagittally and horizontally through
an anti tip M/F ratio of 11:1 and an anti rotation M/F ratio of
4:1.
Results in low load deflection ratio during generation of
retraction force in the range of 50 – 200 gms.
Results in no adverse interaction between anti tip and anti
rotation moments during activation.
Could be used in both 0.08 and 0.022 inch slot.
Have limited dimension and allow for faciolingual
adjustments.
The design of the spring influences not only the M/F
ratio but also load deflection rate the addition of helices
lowers the load deflection rate. It can be changed by changing
the wire composition. TMA (Titanium Molybdenum Alloy)
decreases load deflection rate when compared to stainless
steel.

Types of cuspid retraction springs
Ricketts maxillary and mandibular cuspid retraction
spring.
PG (Poul Gjessing) canine retraction spring
Burstone T loop attraction spring.
A nickel titanium canine retraction spring.

Ricketts Retraction Spring
Maxillary cuspid retraction spring
- Is a double vertical helical extended crossed T closing
loops spring which contains 70mm of wire.
- It produce 50 gm per mm of activation
- Because of additional wire used in its design and all
loops are being contracted during its activation.
- 3 – 4 mm of activation are sufficient for upper cuspid
retraction.

Mandibular cuspid spring
- Is a compound spring with a double vertical helical
closing loop.
- Contains 60mm of wire .
- Made of 16 x 16 blue elgiloy.
- Produces 75gm of force / mm of activation.
- 2-3mm of activation is required to produce the desired
force.
Precautions to be used
At initial placement, a gable bend of approx. 90° is
essential so that the canine and molar do not tip excessively.
Activation in the upper arch is 3-4mm at each adjustment.
In older adults, the activation is 1mm at first visit and
subsequently 2-3 mm.
Lower arch activation has slightly more force / mm of
activation hence activated only 2 – 3mm.
For maximum anchorage cases, Nance holding arch,
lingual arch or utility arch in used.

PG Retraction Spring
Described by Paul Gjessing.
The spring consists of a double ovoid helix with a, smaller
occlusally placed helix.
Available commercially in the preformed version,
constructed in 0.016 x 0.022” SS.
The predominant active element is the ovoid double
helix loop extending 10mm apically.
- It is included in order to reduce the load deflection of
the spring and is placed gingivally so that activation will
cause a tipping of short arm (attached to the canine) in a
direction that will increase the couple acting on the
tooth.
The gentle rounded form avoids the effects of sharp
bends on load deflection.
- The use of large amount of wire in the vertical
dimension leads to maximum reduction of load
deflection.
- Minimizing horizontal wire increases rigidity in the
vertical plane.

Smaller occlusal loop serves to
- Lower the level of activation on insertion.
- Is formed so that activation further closes the loop.
The distal driving force is generated by pulling the distal,
horizontal leg through the molar tube.
A desirable force level of approximately 160 gms is
obtained when two section of double helix are separated by
1mm.
The PG universal retraction spring is designed for
controlled retraction of either canine or upper incisor.
The spring is precalibrated to deliver predictable M/F
ratio in 3 planes of space.www.indiandentalacademy.com

Burstone T loop attraction spring
Made in 0.017 x 0.025” TMA.
Designed for Enmass or separate incisor and canine
retraction in segmented arch technique.
The basic element of the spring is prefabricated highly
standardized universal springs which could be used on
both right and left sides.
These prefabricated versions have to preactivated as per
a prescribed template.
The magnitude of force delivered is identified by reading
the horizontal separation of the vertical legs of the T loop.www.indiandentalacademy.com

Initially M/F ratio is 6 – 8:1 which produce controlled
tipping.
As space close and spring deactivates the force level
decrease and M/F ratio in both alpha and beta arm to
increase, so that the M/F ratio is 10:1 and translations
occurs. Further deactivation increase M/F ratio to 12:1 and
root movement occurs.
Therefore, it is important that this spring is not
reactivated too soon. If reactivated too frequently the teeth
would undergo only tipping.
The T loop is available in 2 heights
a. Regular / long height
b. Short height
Activation is 3 – 4 mm.www.indiandentalacademy.com

During canine retraction because the force is applied
buccal to centre of resistance, a moment is produced on
canine which cause distal in rotation of canine.
There are 4 ways to counter acts these,
- Simultaneously applying a force from the lingual.
- Placing antirotation bends in spring at the ears, vertical
arm or to horizontal arm producing an angle of 120°.
- Using a optimally stiff buccal arch wire.
- Placing cuspid to cuspid stabilizing segment
A Nickel Titanium canine retraction spring
Described by Bourauel and Colleagues.
Spring consist of simple vertical closing loop with antitip
and antirotation bends.
Constructed in 0.016” x 0.0022” Titanal
Spring available in two loop heights, 8mm and 10mm.www.indiandentalacademy.com

Advantages
Ability to use it without a preliminary leveling stage.
It can simultaneously retract the canines and level the
posterior teeth.
Its light, continuous force allows an activation of as much
as 10mm to complete canine retraction without reactivation
of the closing loop.
Few more new methods of canine retraction
Rapid canine retraction through distraction of the
periodontal ligament.
Dentoalveolar distraction osteogenesis for rapid
orthodontic canine retraction.
Retraction using rear earth magnets.www.indiandentalacademy.com

Rapid canine retraction through distraction of the
periodontal ligament.
Canine distraction device
is placed close to center
of resistance to achieve
bodily movement
Surgical techniques for
undermining interseptal
bone distal to canine. No
cuts are performed on
buccal and lingual plates.
Note depth and position
of undermining grooves
Buccal view Occlusal view

Liou and Huang (1998) stated that the process of
osteogenesis in the periodontal ligament during orthodontic
tooth movement is similar to the osteogenesis in the
midpalatal suture during rapid palatal expansion. They
proposed a new concept of ‘distracting the periodontal
ligament’ to elicit rapid canine retraction in 3 weeks. They
coined the term ‘dental distraction’ for this procedure. At
the time of first premolar extraction, the interseptal bone
distal to the canine was undermined with a bone bur,
grooving vertically inside the extraction socket along the
buccal and lingual sides and extending obliquely towards
the socket base. Then a tooth borne, custom made intraoral
distraction device was placed to retract the canines into the
extraction space. The anchor units were the second
premolar and first molar.www.indiandentalacademy.com

Both the upper and lower canines were distracted 6.5
mm into the extraction space within 3 weeks. New alveolar
bone was generated land remodelled rapidly in the mesial
periodontal ligament of the canines during and after
distraction. It becomes indistinguishable from the native
alveolar bone 3 months after distraction. During the
distraction, 73% of the first molars did not move mesially
and 27% of them moved mesially less than 0.5mm within 3
weeks. The radiographic examination revealed that apical
and lateral surface root resorption of the canines was
minimal. They concluded that the periodontal ligament
could be distracted to elicit rapid canine retraction without
complications. This innovative approach can significantly
reduce orthodontic treatment time and merits further
investigation.

Dentoalveolar Distraction Osteogenesis for rapid
orthodontic canine retraction
Dentoalveolar distraction of the right upper canine tooth. A, initial view
before treatment. B, Day 2 of the distraction. C, Day 9 of the distractionwww.indiandentalacademy.com

The aim of this clinical study was to establish an
approach to reduce the overall orthodontic treatment time
by means of dentoalveolar distraction osteogenesis.
The principles of distraction osteogenesis by means of
transportation of bone disc are used to move a
dentoalveolar segment.
In this method first premolar was extracted, and the
buccal bone was carefully removed. After wound closure, a
special orthopedic device was mounted and cemented to
the first molar and canine teeth.
Distraction was started the same day at the rate of 0.4
mm twice a day and continued until adequate movement of
the canine teeth was achieved.
The device was then removed, and orthodontic therapy
was continued with fixed appliances.www.indiandentalacademy.com

Canine retraction using rear earth magnets
Constant force delivery system by rate earth block magnets,
this system did not require reactivation, as loop was kept
open by the magnetic force for entire experimental periodwww.indiandentalacademy.com

CONCLUSION
No single technique suits every situation. EOT
hooked directly on to the arch wire, and sectional arches
are the two most versatile techniques because both
bodily and tipping movement are possible. Each
technique has its limitations thus the individual operator
must choose the method he / she prefers.

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Canine retraction /certified fixed orthodontic courses by Indian dental academy

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