Self ligating brackets /certified fixed orthodontic courses by Indian dental academy

SELF LIGATING BRACKETS
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


CONTENTS:
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INTRODUCTION.
CLASSIFICATION.
HISTORICAL PERSPECTIVE OF SELF
LIGATING BRACKETS.
COMPARISON OF SELF LIGATED AND
LIGATED BRACKETS.
BENEFITS OF SELF LIGATING
BRACKETRS.



THE SPEED SYSTEM.

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THE DAMON BRACKET.

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THE IN-OVATION BRACKET.

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CONCLUSIONS AND REFERENCES


INTRODUCTION:

A truly efficient orthodontic Edward angle’s
edgewise appliance introduced (1928)
represented the culmination of years of work
and many variations in orthodontic appliance
design.

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appliance must provide superior predictability
and control.
The appliance must enhance, and not inhibit
treatment progress.

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The appliance must also be aesthetically pleasing,
and must enable good oral hygine.
The twin edgewise bracket is a passive appliance
that independently is unable to effect and control
tooth movement because it relies on a ligature to
secure it to the arch wire.
The inherent limitation imposed by this bracketligature- arch wire relationship ultimately
compromises the clinical efficiency of the appliance.
The self- ligating brackets transcends the limitations
imposed on design by providing treatment efficiency
and precise tooth movement


SELF- LIGATING BRACKETS:
ACTIVE VERSUS PASSIVE.

Passive and Active
•Passive brackets use a rigid, movable
component to entrap the arch wire.
•Tooth control by passive bracket is
determined solely by the fit between
bracket slot and the arch wire.

Active brackets:
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Active brackets use a flexible component to
entrap the arch wire.
This constrains the arch wire in the arch wire
slot and has the ability to store and
subsequently release energy through elastic
deflection.
A self – ligating bracket : “a bracket, which
utilizes a permanently installed, moveable
component to entrap the arch wire.”


CLASSIFICATION:-


HISTORICAL PERSPECTIVE:
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The first patent for a self-ligating attachment,
the Boyd band bracket, was filed by Charles.
E. Boyd (1933).
Later James. W. Ford filed a patent for the
Ford lock design, which was manufactured
by the Dee Gold company of Chicago,
Illinois.
This bracket was reintroduced by his son
William F. Ford.(1951),but it was primarily
marketed for Johnson twin wire technique.

Boyd band bracket


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The Edgelok bracket was the first self-ligating
bracket designed to enjoy any sort of
commercial success. (1971)
Another design was found in 1980’s called
Mobil – Lock. Both were passive brackets that
achieved limited acceptance in orthodontic
community.
In the mid 1970’s an entirely new generation of
self-ligating appliance began, one that was
active not passive, G.H. Hanson’s SPEED
appliance was a revolutionary step in
orthodontic bracket design.

Edgelok bracket

Mobil-lock bracket

SPEED bracket


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In (1986) the obsolete self ligating Activa
bracket designed by E. Pletcher, also offered
an alternative to conventional ligation. Some
deficiencies, such as the ease with which the
patient could open the bracket, and the
excessive mesiodistal width, led to its
commercial demise.
The next self-ligating design, the Time
bracket entered the market place in 1995.
This is largely a passive self-ligating
mechanism.

Activa bracket

Time bracket




One year later in 1996,the Damon bracket was
introduced, named the Damon SL I. This design
was passive, and because of problems with the
bulky slide and limited tooth control, its commercial
life span was short.



The Twinlock bracket was A.J. Wildman’s second
endeavor, after Edgelok bracket.

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The Twin lock bracket was modified slightly and
renamed as Damon II bracket. The bracket is now
named as Damon 2 bracket.


Damon SL 1 bracket

Twinlock bracket

Damon 2 bracket


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In (2004) a passive, hybrid composite- metal
bracket, the Damon 3 bracket was found.

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The introduction of In - Ovation bracket in
2000 was an attempt, similar to the Damon
design. The Elgiloy spring clip renders the In
– ovation an active self-ligating appliance.


Damon 3 bracket

In-Ovation-R bracket


Comparison of self- ligated and ligated
brackets:
Ligation stability
Ligation
Force level
Friction
Sliding mechanism
Office visits
Treatment time
Esthetics
Patient comfort
Oral hygiene
Infection control
Instruments
Staff

Benefits of self-ligating
brackets:
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Self-ligating brackets result in greater patient
comfort, shorter treatment time, reduced chair
time, and greater precision and control of tooth
translation.
Self-ligating bracket design permit the use of
lighter force levels and impart lower frictional
forces compared with ligated brackets.
Friction during tooth translation is reduced
significantly, due to elimination of steel or elastic
ligatures.

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Self-ligating brackets has been reported to
reduce the risk of percutaneous injury and the
potential for transmission of hepatitis B virus,
hepatitis c virus, or human immunodeficiency
virus for the orthodontist and the support
staff, self-ligation decreases the possibility of
soft tissue laceration and infection from the
cut end of ligature ties.
The elimination of tie – wings and other type
of food traps on some self-ligating bracket
designs significantly elevates the hygiene
level of all patents.

BRACKET PLACEMENT:
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

Care must be taken to position the
miniaturized SPEED brackets as accuratly
as possible to enhance the action of the
spring clip in tooth positioning.
few key points to assist accurate
bracket placement:
The curved spring portion of the SPEED
bracket should be positioned occlusally in
both arches.

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
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The upper brackets are positioned to conform
to an arch wire plane compatible with
brackets placed as far gingivally as possible
on the typically short clinical crowns.
Use of single SPEED brackets on the
upper molars has significant
advantages:
Rotation control offered by the spring clip
creates a superb molar rotation.
Longer span between molar brackets
provides for more efficient use of
compression coil springs for molar
distalization.



Use of a bracket on the terminal molars
enables rapid arch wire changes, in situations
where the ends of arch wire have been
cinched back.



To avoid occlusal interference problems on
the lower first and second molars, use of
miniaturized mandibular tubes rather brackets
is recommended.


THE SPEED SYSTEM:
Introduction of vastly improved arch wires, the
evolution of the preadjusted appliances, and
the perfecting of the various bonding
techniques stands out as major milestones in
the advancement of the art and science of the
clinical orthodontics.
 A new edgewise appliance was developed for
introduction to our profession, to facilitate arch
wire changes and to permit the application of
corrective forces.



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More than 600 patients have undergone
treatment with this new appliance.
The acronym SPEED has been chosen to
identify the appliance and the system of
treatment which is continuing to evolve with
its use.
The name is derived from the descriptive
terms Spring-loaded, Precision, Edgewise, Energy, and
Delivery, all of which describe the design.
The main component of the
appliance are, mutilated bracket body, a
spring clip, and a foil- mesh bonding bases.

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The spring clip: Highly resilient spring clips are
formed from a high tensile 17-7 precipitationhardening 0.005 by 0.006 inch stainless steel
strip.
This has a short labial arm joined to a longer
lingual arm by an 0.025 inch.
After forming and prior to assembly, the
springs are precipitation hardened for 1 hour at
900 degree.
The bonding bases: The bonding pads are just
wide enough for a secure laser seam weld to
each bracket flange.

Labial, mesial and distal edges of each pad
are parallel to one another and angulated
relative to the occlusal edge required by the
type of the tooth to which it has been
assigned.
 All pads requiring mesiodistal curvature are
bent about a central axis parallel to their
mesial and distal edges.
 Bracket-spring assembly: The spring clip is
mounted on the bracket body, and when the
spring is in the slot-closed position, its arms
are held apart to reduce their angle.
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Mounting the spring on the bracket body in the
slot-closed position converts the arch wire slot
into a trapezoidal tube having three rigid walls
an elastic inclined labial wall.
Welding the bracket-spring assembly to its
bonding base transforms the vertical lingual
slot into a lingual arm of the clip in a closetolerance fit.
Operation of the SPEED bracket: The spring is
opened by approximately 10 ½ ounces of
occlusally directed force to the gingival edge.

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Once the gingival edge of its labial arm has
passed over the short ledge immediately
occlusal to the arch wire slot, the spring
appears to jump the rest of the way into its
parked-open position by itself.
The spring clip can be returned to the slotclosed position by application of a light
gingivally directed force.
During insertion, an arch wire must be held all
the way into the slot, at least until the labial
arm of the spring clip has trapped it.

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•

The SPEED appliance has been designed for
precise rotational control about three axes:
The occlusogingival axis (rotation).
The labiolingual axis (tipping).
The mesiodistal axis (torque).
Rotational control about the occlusogingival axis: The bracket
and the entrapped arch wire bear a relationship to
one another, where only least amount of elastic
strain imparts to the spring clip.
No rotation of the bracket around the
occlusogingival axis away from this position is
possible without additional elastic deformation of the
spring.

•

The spring clip is holding the arch wire captive and is
subjecting it to a 15 degree counterclockwise bend
The arch wire is deflecting the labial
arm of the spring clip labially and distally and also
giving it a clockwise twist.
Rotational control about the faciolingual axis: The
effectiveness of an edgewise appliance in controlling
tooth tipping is dependent on the size of the arch
wire and bracket slot used.
A tight fit between the arch wire and
the bracket slots can cause excessive frictional
binding.


•

The SPEED appliance permits improved
control over tipping movements, a higher
degree of constancy of light force, and a
reduction in the frictional resistance to sliding
movements.
Rotational control about the mesiodistal axis: (torque
control ) – The SPEED appliance is designed
for a high degree of control over labiolingual
tooth tipping, similar to all edgewise
appliance.

TECHNIQUE



Clinical experiences taught some points when
using the SPEED appliance:
The curved portion of the bracket should be
directed toward the occlusal in both arches so
that the spring which wraps over it will always
be to move into the slot-open position.
Lower brackets should be positioned far
enough gingivally to avoid even the lightest
occlusal interference.


Unless overrotation are required, each bracket should be
centered on the middle lobe of the tooth, with its mesiodistal
slot axis parallel to a tangent drawn to the lobes curvature at
its midline.
Because of their small size and individualized compound
curvature, SPEED bracket bases require very little fitting.
Accurate placement of brackets is aided by bearing in mind
that the occlusal edge of each bonding pad is parallel to the
arch wire slot.
An excellent instrument for opening and closing the bracket
spring clips is a Silverman PD-1 band pusher and director.


ARCHWIRE HOOKS FOR THE
SPEED SYSTEM:
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The SPEED Arch Wire Hook permits the use of
interarch or intra-arch elastics with any size or
shape of arch wire.
The hook consists of a tapered, split inner male
component that rests, by a friction fit, inside a
slightly less tapered outer female collar.
The SPEED Arch Wire Hook has three
major advantage:
It will never move or creep along the arch-wire, as
the male and the female.components are squeezed
together.

B
A


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Its load and lock process is extremely simple
and fast. The hook saves chair time.
It was specifically designed to provide a secure
method of applying force to a wire of any
material.
Technique:
Seat the arch wire in the open SPEED bracket
slots. The preassembled positions of the inner
and outer components help align the split
portion of the inner sleeve with the outer hook.
Be sure that the hook assembly of the
outer female component is facing in the desired
direction for elastic traction.

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Rotate the outer sleeve with the hook to the
desired bucolingual position, using a fine
ligature director, while holding the SPEED
hook in the marked on the arch wire.
With gentle, but firm, plier pressure, guide and
then squeeze the tapered, split inner male
component into the outer female component,
without disturbing the archwire hook.
The technique described above is a simple,
quick and highly accurate means of adding a
SPEED hook to any arch wire. No laborious
soldering is required.

SUPERCABLE AND THE
SPEED SYSTEM:
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Round and rectangular multistranded cables
such as Wildcat and Respond have been
wildly used, but are still limited by the
mechanical properties of the stainless steel.
In 1985, Burstone and colleagues reported on
a new superelastic Chinese nickel titanium
wire with a spring back 50% greater than
nitinol and 400% greater than stainless steel.

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In 1993, Hanson combined the mechanical
advantages of multistrand cables with the
material properties of superelastic wires to
create a superelastic nickel titanium coaxial
wire, called the Supercable.

The resulting loading and the unloading forces
were measured by the Instron machine.
 It was found that both .016” and .018”
Supercable wires exerted only 36-70% of the
force of .014” solid nickel titanium wires.



CLINICAL USE OF
SUPERCABLE:
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Most clinically significant finding was that the .
016” and the .018” Supercable wires were the
only , that tested at less than 100g of un loading
force over a deflection range of 1-3mm.
Supercable thus demonstrates optimum
orthodontic forces for the periodontium. As
directed by Reitan and Rygh (1986).
It also offers the clinician the advantage of
engaging a relatively large arch wire at the start
of the treatment.

Supercable offers the following
advantages when
combined with SPEED bracket
system:
.Minimal patient discomfort.
Improved treatment efficiency.
 Simplified mechanotherapy.
Elimination of arch wire bending.
More effective and efficient control of
rotational, tipping, and leveling mechanics.
No evidence of anchorage loss
Minimum patient discomfort.

DISADVANTAGES:
•
Tendency of the wire to fray if not
cut with sharp instrument.
•
Tendency of the arch wire to break
and unravel in extraction spaces.
•
Inability to accommodate bends,
steps or helices.
•
Tendency of the wire ends to
migrate distally, and occasionally irritate
soft tissues.

THE DAMON BRACKET:
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The Damon system achieves the biologically
induced tooth moving force, by means of a
passive, virtually friction free, self-locking fixed
appliance that maximizes the full potential of
today’s high-tech arch wires.
The clinical results indicate that clinicians can
maintain most complete dentitions, even in
severely crowded arches, by using very light-force,
high-tech arch wires in the passive Damon
appliance that alter the balance of forces among
the lips, tongue, and muscles of the face.
The author refers this phenomenon as
“physiologically determined” tooth positioning.

Early observations of Damon system:


Dwright H. Damon first started using this new passive tube
tecnology in the mid 1990’s, it became obvious that
alveolar bone, tissue, and teeth responded differently from
those treated with conventional high-force mechanics.
The system offers minimal negative impact on the arch
form when aligning severely malpositioned teeth.
With this tube technology and lowforce, low-friction mechanics, adverse effects like intrusion
and flaring are minimized or eliminated.


The appropriate force and wire-to-lumen ratio
produces a frankle-type arch-widening effect in the
posterior, while lower canine width stays
approximately same.
The orbicularis oris and mentalis muscles create a
lip bumper effect, which minimizes anterior
movement of the incisors.
In cases treated with nonextraction, as it widens in
the posterior, the tongue usually lifts and moves
forward, creating a new force equilibrium between
it and the lips and muscles of the face.
In bimaxillary protrusive cases treated through
extraction therapy, treatment mechanics are
simplified greatly with the lip bumper or headgear
effect of the facial muscles minimizing the demand
on posterior anchorage.

FORCE MANAGEMENT:
The means of achieving
extremely light-force mechanics:
(a passive tube)
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The author has spent nearly 20 years carefully
evaluating the rationale for his clinical mechnics.
One of the earliest tube systems, the twin-wire capand-channel appliance, possessed some of the
attributes of current self-locking systems.
Unitek introduced an appliance in 1966, its Snap
Ring appliance, that was not self ligating, but
simulated the concept.

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A later example was the edgelok bracket
which was introduced in the late 1960s,was
the first “true self-ligating tube-type appliance.”
It was comfortable and had a positive-seating
mechanism.
Another major advancement of that era was
the SPEED appliance (an active self-ligating
appliance). Here arch wire changing chair time
reduced to as little as 25% of that of
conventional twin bracket.
George Anderson introduced the space-age
nickel-titanium wires.

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Maximizing treatment results, requires a passive selflocking appliance (tube) combined with careful
selection of arch wires and timing.
The Damon bracket meets these demands to meet
the optimal force range that stimulates cellular activity
without blood flow in the periodontium.
Using extremely light forces in passive tube:
Using scanning microscopy, Carl Sandstedt (1904)
discovered the different responses of tissue to heavy
and light orthodontic forces.
The Damon system, when properly applied provides
patients with the physiological improvement.



Light wires acting in almost friction-free
environment in the Damon tube appear to
correct the functional imbalance and allow the
alveolar process to create new arch form.



Moving teeth with high-tech arch wires in
passive self-locking tubes generates a healthy
alveolar bone and periodontium support that is
not as susceptible to relapse.


Damon system appliance:
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The preadjusted Damon appliance is available in
0.022”and 0.018” slots.
This appliance when used with the recommended
arch wire, allows faster, unrestricted tooth movement
and a more comfortable patient.
Opening the slide in the latest D3 version is done by
a opening tool, whereas closing is by finger pressure
.
Mechanics is based on achieving the following two
clinical properties: high-force mechanics should not
be used during any phase of treatment, and work
with the orofacial musculature.

THE IN-OVATION BRACKET :


THE IN-OVATION BRACKET IS THE WORK OF
DIFFERENT PERSONS- Andrews, Roth, and Voudouris.
This bracket has created a revolution in time saving for the
patient and the orthodontist.
CONCEPT OF THE IN-OVATION
BRACKET:



This bracket is a true straight wire appliance.



The bracket base is contoured occlusogingivally or
incisogingivally and mesiodistally.



Rotation, in-out, and torque are built into the bracket base.




ADVANTAGES OF INOVATION OVER OTHER SELF
LIGATING SYSTEMS:
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True fully adjusted three-dimensional
appliance.
Accurate Roth prescription.
Interactive closing spring.
No breakage of lock mechanism.
Total torque control with no compromise
result.
Rapid, dependable opening and closing
mechanism for arch wire change.

COMPARISON TO OTHER BRACKETS:




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Currently, the Damon bracket is the only selfligating straight wire bracket, but the lock
mechanism is passive rather than interactive.
The interactive closing clip mechanism
minimizes friction in the early stages of
treatment, when low friction is advantages.
The two major problems of passive selfligating brackets are:
Inability to control torque and the breakage of
the lock mechanism.



The Smart clip” self – ligation appliance
system revolutionizes self-ligation. An integral
nikel-titanium clip permits easy and simple
arch wire insertion and removable, yet holds
the arch wire with a pre-programmed force
that avoids unintentional disengagement.



The Smart clip bracket also features a similar
twin bracket design and the MBT system
prescription.




Choose either the APC” II adhesive coated
appliance system or the APC” plus system
with color change adhesive for greater
efficiency. These features , exclusively
together with Smart clip appliance system
combine to bring unmatched efficiencies and
more predictable outcomes of orthodontic
treatment.


A Comparative study of conventional
ligation and self-ligating bracket system:


With the introduction of the Edgelok bracket in 1972,
the SPEED system in 1980, and the Activa in 1986,
reported a significant reduction in the level of friction,
in addition to shorter treatment time and chair time,
when compared with conventional bracket system.

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A greater demand is placed on the doctor-staff time
to maintain the same level of efficiency in the patient
care.


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The sample consisted of five different types of
o.o22 X o.o28 inch brackets.
Each brackets were mounted on a acrylic
cylinder and an 0.018 inch arch wire was
ligated into each bracket slot.
Frictional force was calculated using the
universal testing instrument.
The results showed no statistical difference in
the force values to initiate wire movement for
the Activa, Edgelok, SPEED, and the twin
bracket with the metal tie.



The use of the elastomeric power module
revealed a higher level of mean frictional
resistance of 3.07 ounces with the SPEED
bracket system when compared with Activa
bracket system (12.64 ounces) or the Edgelok
bracket system (1.42 ounces.



The time involved to open the self-ligating
brackets illustrated a significant decrease in
time when compared with the conventional
ligation method.

Time Savings with Self-ligating brackets:
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

Despite a wide range of protective techniques
for sterilization and infection control,
orthodontists are still exposed to infectious
hazards. The possibility of puncture wounds
from ligatures raises the question whether to
use ligatures.
Self-ligating brackets were introduced in 1970s
and include the SPEED appliance and Mobilok
and Quicklok brackets.

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Using the self-ligating brackets frees an
additional few minutes of the appointment for
positive reinforcement of proper oral hygiene.
Two patients of self-ligating can be scheduled
in the time of one conventional half-hour arch
change appointment.
Manufactures of self-ligating brackets have
always emphasized the advantages of
improved esthetics and comfort.
The reduced chair time is another significant
advantage of the self-ligating brackets –
whether the time is used to schedule more
patients, or increase practice efficiency.

A prospective survey of percutaneous
injuries in orthodontists:




Last two decades has seen an increaseed
awareness of occupational injury, and a
dramatic increase in HIV patients and
Hepatitis B has been an lethal
consequences to the health care provider.
A stratified random sample of practicing
orthodontists were used, 2800 orthodontists
were used to complete the survey.








The results of this study indicate that the
orthodontists have a rate of percutaneous
injury that is low in relation to most other
generalists and specialist in dentistry.
The largest number of injuries was associated
with the manupulation of the arch wires,
although burs, scalers, explorers, and rotary
disks were also involved.
The majority of the percutaneous injury
occurred during arch wire changes were to the
index finger and thumb.

Conclusion :
As more orthodontic practices
embrace the concept of self-ligation. It is
becoming apparent that stainless steel and
elastomeric ligatures will eventually be as
out dated as full banding is today.
Considering the advantages of selfligating brackets for the clinician, staff and
patient, they may well become the
“conventional” appliance systems of the 21st
century.

REFERENCES:


GRABER, VANASDAL – ORTHODONTIC PRINCIPLES :
2004



Dr. G. Herbert Hanson :- The SPEED system: A report on the
development of a new edgewise appliance; AJO : 1980 Vol
78.



Jeffrey L. Berger : The influence of the SPEED bracket’s selfligating design on force levels in tooth movement: A
comparative in vitro study; AJO-DO : 1990 vol 97.



Jeffrey L. Berger : The SPEED appliance :A 14- year update
on this unique self-ligating orthodontic mechanism; AJO-DO
march 1994: vol 3.










Robert A. Bagramian, James A. McNamara : A
prospective survay of percutaneous injury in
othodontists; AJO-DO december 1998 : vol 114.
Rolf Maijer, and Dennis C. Smith : Time saving with
self-ligating brackets; JCO january 1990: vol 24.
Prasanna Kumar Shivapuja, and Jeff Berger : AJODO november 1994; vol 106.
Susan Thomas, Martyn Sherriff, and David Birnie : A
comparative in vitro study of the frictional
characteristics of two types of self-ligating brackets
and two types of pre-adjusted edgewise brackets tied
with elastomeric ligatures; EJO 1998 : vol 20.






Jeff Berger: Self-ligation in the year 2000; JCO
February 2000: vol 34.
G. B. Read-Ward, and S. P. Jones: A
comparison of self-ligating and conventional
orthodontic bracket system; BJO 1997: vol 24.


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