Removable orthodontic appliances /certified fixed orthodontic courses by Indian dental academy

REMOVABLE
ORTHODONTIC
APPLIANCES
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

• Treatment with removable appliances will not provide the
best answer to every orthodontic problem.
Some small degree of irregularities are impossible to treat
with removable appliances and some severe malocclusions
respond well.“
Philip Adams

Source: AJO-DO Volume 1969 Jun (10 - 19):
Orthodontics in practice and perspective - Salzmann

www.indiandentalacadem
y.com

REMOVABLE ORTHODONTIC
APPLIANCES
Removable orthodontic appliances
are devices that can be inserted into and
removed from the oral cavity by the patient
at will.

y.com

.

Removable appliances are considered to be of two
kinds—
(1) appliances which are clasped to the teeth and
are referred to as fixed plates and
(2) removable appliances, which are those that lie
loosely in the mouth and produce their effect by
modifying the pattern of activity of the orofacial
musculature and hence the pressures produced on
the teeth by these activities.

y.com

HISTORY:• VICTOR HUGO JACKSON was the chief
proponent of removable appliance. (1904)
• The crib clasp has a square form and grasps the tooth
buccally and also anteroposteriorly . It is difficult to make
the wire fit buccally and anteriorly and posteriorly as well,
even if an accurate impression of these areas can be
obtained. It is impossible to obtain a good fit if the
anteroposterior surfaces are hidden by gingival tissue. It is
better to use either the mesial and distal undercuts or the
buccal undercut, but it is unwise to try to use them both, as
in this event neither is properly effective.
•Volume 1969 Jun (202 - 218): Removable appliances yesterday
and today - Adams www.indiandentalacadem
y.com

HISTORY:•In early 1900’s, GEORGE CROZAT
developed a removable appliance fabricated
entirely of precious metal which consisted of an
effective clasp for 1st molar modified by
JACKSON’S design. He gained contact with the
mesial and distal undercut areas by fixing an
additional short length of wire to the loop of a
plain crib clasp and causing the ends of this
additional wire to run round the gingival
margin and make contact with the tooth
anteroposteriorly
y.com

HISTORY:• Attempts to improve the clasping of teeth on the lingual side,
that is, by gaining access to the lingual undercut area by means
of a fine spur which lies in the lingual gingival sulcus (Visick,
1926) or by using the anterior and posterior undercut areas
from the lingual aspect by adding small spurs soldered to the
tags of clasps of the crib type. Devices of this kind did
certainly improve the effectiveness of crib clasps, but they also
tended to be time consuming to make, delicate, troublesome
to adjust, and likely to cause discomfort, and they required the
use of precious metals.

y.com

HISTORY:Schwarz designed the
arrowhead type of clasp, which was
introduced in England by Tischler.
The clasp demands considerable amount of space in the oral
vestibule. Special instruments are entailed in its construction,
and fabrication and adjustment are fairly complex operations.
The arrowhead clasp, however, made use of the best principle
of clasp design— the use of the mesial and distal undercuts—
but there appeared to be room for improvement in the
working out of this principle in practice.
y.com

HISTORY
The modified arrowhead clasp, introduced by ADAMS
in 1949 and today widely referred to as the Adams clasp,
makes use of the mesial and distal undercuts of a single
tooth only and can in practice be applied to any tooth,
deciduous or permanent.
• Since the clasp was given its definitive
form in 1953, no changes in the basic
principle and design have been found
necessary

y.com

FUNCTIONAL APPLIANCE

by definition is the one that changes the posture of the
mandible, holding it open or open and forward.
Passive tooth borne :-

Activator, Bionator,
Herbst appliance, Twin block.
Active tooth borne :Modifications of
Activators and Bionators.
Tissue borne appliances :- Frankel appliance.

y.com

ADVANTAGES OF REMOVABLE
APPLIANCES :Pt can continue oral hygiene procedures without any
hindrance.
Tipping movement of teeth can be carried out.
Appliance more inconspicuous, hence generally more
acceptable to patients.
Relatively simple appliance can be delivered and monitored by
general dentist.
Can be removed on socially sensitive occasions, hence more
acceptable to patients

y.com

ADVANTAGES
Appliance fabrication is done in specialized labs,hence
chair side time is considerably less than fixed appliance.
Since few movements are carried out simultaneously with
these appliances the time required to activate an
appliance is less.
Appliance require simple inventory to be maintained as
compared to complex fixed appliance.
Appliance are relatively CHEAP.

y.com

DISADVANTAGES :Patient co operation.
Capable of only certain types of movements.
Multiple movements are difficult if not impossible.
Patient has to have certain amount of dexterity and
skill to remove and replace the appliance.
Chances of appliance “BREAKAGE and LOSS” .

AJO-DO Volume 1985 May (392 - 397): Patient cooperation in
treatment with removable appliances - Gross, Samson, and Dierkes
y.com

INDICATIONS
Growth modification
Limited tooth movements like tipping, etc especially for arch
expansion or correction of individual tooth malpositions
Retention after comprehensive treatment

y.com

GENERAL PRINCIPLES OF
REMOVABLE APPLIANCES :Appliance works by tipping of tooth around is center of resistance, which is
located between 30 – 40 % from root apex.
FORCES EXERTED ARE DEPENDENT ON :

• KIND OF APPLIANCE
• HARNESSING OF FORCES FROM ADJACENT HARD
AND SOFT TISSUES,INCORPORATION OF SPRINGS
AND ELASTICS.
• TYPE OF CONTACT THE APPLIANCE MAKES WITH
THE TOOTH.

y.com

Components of Removable
Appliances :• RETENTIVE COMPONENT

• ACTIVE COMPONENT
• BASE PLATE

y.com

RETENTIVE
COMPONENTS

y.com

• Helps in keeping the appliance in place and resists
displacement of the appliance.
• Success depends to a large extent on GOOD
RETENTION of appliance.
• They do not bring about necessary tooth movement.
• Adequate retention of a removable appliance is achieved
by incorporating certain wire components in undercut area
called as CLASPS.

y.com

MODE OF ACTION
• Act by engaging certain areas of tooth called UNDERCUTS.
• The wire is made to engage these undercuts to prevent
displacement of the clasp.
TYPES OF UNDERCUTS :• BUCCAL AND LINGUAL

• CERVICAL UNDERCUTS.
• MESIAL AND DISTAL
PROXIMAL UNDERCUTS.
y.com

IDEAL REQUIREMENTS OF
CLASP :Offer adequate retention.
Permit usage in both fully and partially erupted teeth.
Offer adequate retention even in presence of shallow
undercuts.
By themselves should not apply any force.
Be easy to fabricate.
Not impinge on soft tissues.
Not interfere with normal occlusion.

y.com

DIFFERENT CLASPS :1.
2.
3.
4.
5.
6.
7.
8.

Circumferential clasp.
Jackson’s clasp.
Adam’s clasp.
South end clasp.
Triangular clasp.
Ball end clasp
Schwarz clasp.
Crozat’s clasp.

y.com

CIRCUMFERENTIAL CLASP :-

• Also known as “three quarter clasp” or C clasp.
• Simple clasp designed to engage bucco-cervical
undercut.
y.com

• 0.9 mm stainless steel wire is engaged from one proximal undercut
along the cervical margin then carried over occlusal embrasure to
end as a single retentive arm on the lingual aspect embedded in
acrylic base plate.
• USE : - Molars and premolars, canines
• ADV : - Away from occlusal contact
Simplicity of design & fabrication.
• DIS : - Cannot be used in partially erupted teeth as cervical
undercut is not available
- Cannot be used on deciduous teeth as there is no
infrabulge area
Skip demo
y.com

Straightened piece of wire.
Skip demo
y.com

Use the pliers as a vice to bend
the wire. First make a bend in
the wire smoothly in a
semicircularwww.indiandentalacadem
shape
y.com

Skip demo

Proceed further following the cervical
margins
Skip demo
y.com

Checking that the clasp fit into
marked undercuts of tooth.
y.com

Skip demo

Bend wire down from over contact
point towards the palate
y.com

Skip demo

The wire passes vertically over the occlusal
embrasure
Skip demo
y.com

At the level of the marginal ridge the
wire is bent towrds the palatal surface
y.com

Skip demo

The wire ends as a retentive arm
palatally.

y.com

Skip demo

JACKSON’S CLASP : -

• Introduced by JACKSON in 1906.
• Also called as U clasp, Full clasp
y.com

• Clasp engages bucco-cervical undercut and also
mesial and distal undercut.
• 0.9 mm stainless steel wire is adapted along buccocervical margin n both occlusal embrasures to end
retentive arm on both sides of the molar.
• USE: for retainer
Molars, canine, premolars
• ADV : - simple to construct and adequate retention
• DIS : - inadequate retention in partially erupted teeth
and deciduous teeth.

y.com

Straighten a piece of 0.9
mm stainless steel wire

Skip demo
y.com

Adapt the wire to pass around the
buccal surface of tooth to pass
above the cervical margin
y.com

Skip demo

Mark the point at the level of the
bucco proximal line angle
y.com

Skip demo

Bend the wire such that it passes over
the occlusal embrassure
y.com

Skip demo

The wire being adapted from
over contact point into the
palate
Allowing a space of 1mm for
acrylic to flow underneath the
wire

y.com

Skip demo

Clasp in final position
Skip demo
y.com

ADAM’S CLASP

• First described by PROFESSOR PHILLIP ADAMS. in 1948
• Also known as LIVERPOOL, modified arrowed, universal clasp. It is a
modification of Schwartz arrowhead clasp.
• This clasp provides maximum retention, when constructed properly.
• Made up of 0.7 mm hard S S wire. for molars and premolars 0.6 mm wire for
canine

y.com

Adam’s clasp is made up of :• 2 Arrow heads.- it engages the mesial and distal proximal
undercuts
• Bridge.- it connects the two arrowhead
• 2 Retentive arms.

y.com

Advantages Of Adam’s clasp :It is RIGID and offers excellent retention. This clasp
develops the maximum retentive potential of whatever
tooth it is placed upon in the simplest and most
unobtrusive way.
Can be fabricated on both Deciduous and Permanent
dentition.
Used on partially and fully erupted teeth.
Used on molars, premolars and on incisors.
No specialized instrument is needed to fabricate the clasp.
Auxiliaries like springs, hooks tubes can be soldered to the
bridge
y.com

• It is small and occupies minimum space.
• Can be modified in a number of ways.
Following are Modifications of the clasp :-

Adam’s with single arrow head.
Adam’s with J hook.
Adam’s with incorporated helix.
Adam’s with additional arrowhead.
Adam’s with soldered buccal tube.
Adam’s with distal extension.
Adam’s with incisors and premolars.
skip demo
y.com

DISADVANTAGES
• If not skillfully made it becomes work hardened and will be
liable to fracture

y.com

Pliers required for constructing
appliances.
y.com

skip demo

A good quality working model cast in stone
is required
y.com

skip demo

ark mesial and distal undercuts for molar arrowhead placement
y.com

skip demo

The position of the Adams Clasp tags
drawn on t
model to ensure they don't interfere with
screws and
springs which may be required .
skip
y.com

demo

Straightened piece of wire.
y.com

skip demo

Use the pliers as a vice to bend the wire. First
make a bend in
the wire slightly more than a right angle . skip demo
y.com

Hold the wire to the mesial mark on
the tooth.
y.com

skip demo

Make a second bend slightly more than a right angle .
y.com

skip demo

he wire to the model to see that the dimensions are correct
y.com

skip demo

Hold in the pliers just below one of the bends
y.com

skip demo

ceed with a further right angled bend .

y.com

skip demo

y.com

Bend completed

skip demo

Right angled bendwww.indiandentalacadem to matchskip demo
on the other side
y.com

Tilt the wire down.
y.com

skip demo

wire is locked against the beak before starting to bend the arro
y.com

skip demo

Bend the arm upwards so it follows the line of th
opening of the beaks of the pliers.

y.com

skip demo

Turn the pliers round, then the wire is pulled back on
itself forming the 'U' type of loop at the bottom of the
arrowhead
skip demo
y.com

he second arrowhead held in the pliers beak prior to ben
y.com

skip demo

The pliers turned to show that the first arrowhead is l
against the beak of the pliers
y.com

skip demo

The wire is now bent
upwards
parallel to the opening of
the beak of the pliers .

y.com

skip demo

mpletion of the bend of the second arrowhead.
y.com

skip demo

Arrowhead being turned in
at 45o to bridge of crib.
y.com

skip demo

arrowheads are bent into 45o from the bridge head.
y.com

skip demo

Turning the arrowhead to 45o to the brid

y.com

skip demo

cking that the arrowheads fit into marked undercuts of
y.com

skip demo

ting to bend the retention arm over the contact point of tooth.
y.com

skip demo

Holding in pliers prior to bend.
y.com

skip demo

Bending arm over beak of pliers.
y.com

skip demo

Straightening out arm.
y.com

skip demo

Put clasp back to model making sure the
arrowheads go into the marked undercuts
and then check the wire goes over the
skip demo
contact point between y.com two teeth
the

ting to bend the retention arm over the contact point of
y.com

skip demo

wire being adapted from over contact point into the palat
ing a space of 1mm for acrylic to flow underneath the w
y.com

skip demo

ng on the model to check adaptation to the contact poin
y.com

skip demo

Clasp in the final position with
Bridge parallel with buccal cusps
y.com

skip demo

Bridge halfway up crown.
y.com

skip demo

ADAM’S WITH SINGLE
ARROWHEAD :-

y.com

ADAM’S WITH SINGLE
ARROWHEAD :• Indication -Partially erupted
tooth which is usually last
erupted molar.
• Single arrowhead is made to
engage the mesio-proximal
undercut of last erupted
molar.
• Bridge is modified to encircle
the tooth distally and ends on
the palatal aspect as retentive
arm.
y.com

ADAM’S WITH J HOOK : -

•J hook can be soldered on to bridge of the Adam’s
clasp.
y.com

ADAM’S WITH J HOOK : -

USEFUL IN engaging elastics
y.com

ADAM’S WITH
INCORPORATED HELIX :-

y.com

ADAM’S WITH
INCORPORATED HELIX :-

Helix is incorporated into the bridge of Adam’s clasp.
This helps in engaging elastics.
y.com

Straighten a piece of wire
y.com

Bend the wire smoothly
around the circular beak of
the plier in approximately
half the length of the wire

y.com

Turn the wire around the beaks to
form a circular small helix
y.com

Hold the wire to the model to mark the mesial and distal under

y.com

nd the wire at the marking at slightly more than a right angle
y.com

old the wire to the model to see that the dimensions are correct

y.com

Proceed to form the
arrowheads as www.indiandentalacadem
in a
y.com

ADAM’S WITH ADDITIONAL
ARROWHEAD :-

y.com

ADAM’S WITH ADDITIONAL
ARROWHEAD :-

Adam’s can be constructed with an additional arrowhead.
Additional arrowhead engages proximal undercut of the
adjacent tooth and is soldered on to the bridge of the
Adam’s.
This type of clasp gives additional retention.
y.com

ADAM’S WITH SOLDERED
BUCCAL TUBE :-

y.com

ADAM’S WITH SOLDERED
BUCCAL TUBE :-

Buccal tube is soldered on to the bridge of Adam’s
clasp.
This modification permits use of extra-oral anchorage
using face bow-head gear assembly.
y.com

ADAM’S WITH DISTAL
EXTENSION :-

y.com

ADAM’S WITH DISTAL
EXTENSION :-

Clasp can be modified so that the distal arrowhead has
a small extension incorporated distally.
Distal extension helps in engaging ELASTICS.
y.com

Follow the technique to make
usual arrowheads

y.com

At the distal
arrowhead, make a
loop just above
y.com

Position of distal
extension
y.com

ADAM’S ON INCISORS AND
PREMOLARS : -

y.com

ADAM’S ON INCISORS AND
PREMOLARS : -

Adam’s clasp can be fabricated on the incisors and
premolars when retention in those areas are required.
It can be constructed to span a single tooth or two teeth.
y.com

SOUTHEND CLASP :• Used when retention is required in
anterior region.
• 0.7mm stainless steel wire is
adapted along the cervical margin
of central incisors.
• Distal ends are carried over
occlusal embrassure to end as
retentive arms on the palatal side.

y.com

TRIANGULAR CLASP : • They are small triangular
shaped clasp that are used
between two adjacent
posterior teeth.
• 0.7mm stainless steel wire is
used
• They engage the proximal
undercut of two adjacent
teeth.
• Indicated when additional
retention is needed.
y.com

BALL END CLASP :• Fabricated using S S wire having a knob
or a ball like structure on one end.
• Ball can be made at the end of wire
using silver solder.
• Preformed wires having ball at one end
are also available.
• Ball engages proximal undercut similar
to triangular clasp.
• Indicated when additional retention is
required.

y.com

SCHWARZ CLASP :• SCHWARZ or ARROWHEAD
clasp is said to be a predecessor
of ADAM’S clasp.
• Designed in such a way that
number of inter-proximal
undercuts between the
premolars and molars are
engaged.

y.com

Disadvantages of this clasp :•
•
•
•

Needs special arrowhead forming pliers to fabricate.
Occupies a large amount of space in the buccal vestibule.
Arrowheads can injure the inter-dental dental soft tissues.
Difficult and time consuming to fabricate.

y.com

CROZAT CLASP :• Resembles a full clasp but has an
additional piece of wire soldered
which engages into the mesial and
distal proximal undercuts.
• Offers better retention than full
clasp.

y.com

ACTIVE COMPONENT

Components which exert force
to bring about necessary tooth
movement.
y.com

Active components include :BOWS
SPRINGS
SCREWS
ELASTICS

y.com

Bows:Active component that are mostly used
for incisor
Following is a list of commonly used bows:
Short Labial Bow.
Long Labial Bow.
Split Labial Bow.
Reverse Labial Bow.
Robert’s Retractor.
Mill’s Retractor.
High Labial Bow With Apron Springs.
Fitted Labial Bow.
y.com

SHORT LABIAL BOW :• It is constructed using 0.7 mm
hard round S S wire.
• It consists of a bow that makes
contact with most prominent
labial teeth and 2 U loops that
end as retentive arms distal to
canines.
• This type of labial bow is very
stiff and exhibits low flexibility.

y.com

• Activated by compressing the U
loops.
• Indicated in cases of minor
overjet reduction and anterior
space closure
• Used for the purpose of retention
at the termination of fixed
orthodontic therapy.

y.com

LONG LABIAL BOW :• It is similar to short labial bow
except that it extends from one
premolar to the opposite premolar.
• Distal arms of U loop are adapted
over the occlusal embrasure between
the two premolars to get embedded
in the acrylic plate.

Activation similar to short labial bow.
Modified form of long labial bow can be made by soldering
distal arm o the bridge.
y.com

Indications : Minor anterior space closure.
 Minor overjet reduction .
 Closure of space distal to canine.
 Guidance of canine during canine
retraction .
 As a retaining device at the end of
fixed orthodontic treatment.
skip demo

y.com

mark the position of the labial bow on the model.
skip demo
y.com

skip demo
y.com

tart with a piece of wire approximately 20cm long to form a
mooth curve, using the fingers to ensure that it touches
l the teeth from canine to canine
y.com

ark the centre of the canine where you wish to bend the 'U' loo
y.com

skip demo

mark the centre of the canine where you wish to bend the 'U' l
y.com

skip demo

Using the round beak to form the 'U' loop
y.com

skip demo

skip demo

The completed 'U' loop.
y.com

Place the wire on the model.
y.com

skip
demo

Commence bending the retention leg.
y.com

skip demo

Bend a small loop at the end of the retention leg
y.com

skip
demo

skip
The completed retention leg replaced on model.
y.com

demo

SPLIT LABIAL BOW :• This is a labial bow that is split in
middle ,that results in 2 separate
buccal arms having a U loop each.
• This type of labial bow exhibits
flexibility.
USE:
 For anterior retraction
 Modified form of split bow used for
closure of midline diastema.
ACTIVATION:
By compressing U loop 1-2 mm at a time.

y.com

NORMAL SPLIT LABIAL BOW

Used for correction of diastema
y.com

REVERSE LABIAL BOW:• Also called Reverse loop labial bow.
• U lops are placed distal to canine and the
free ends of the U loops are adapted
occlusally between 1st premolar and
canine.
USE
• Anterior reduction and anterior space
closure.
ACTIVATION
• done by first opening the U loop and then
compensatory bend given at the base.

y.com

ROBERT’S RETRACTOR:
• This is a labial bow made up of
thin gauge S S wire having a coil
of 3 mm internal diameter mesial
to canine.
• Use of 0.5 mm stainless steel wire
along the incorporation of a coil
makes the labial bow highly
flexible.
• As bow is highly flexible,it lacks
adequate stability in vertical plane.

y.com

• Distal part of retractor is supported in a S S tubing of
0.5 mm internal diameter.
USE:
• Indicated in pts having severe anterior proclination
with overjet of 4 mm.
• As bow is flexible, it generates lighter forces hence can
be used in adult pts whom lighter forces are desirable.

y.com

MILL’S RETRACTOR
• Labial bow has extensive
looping of the wire so as to
increase flexibility and range of
action.
• Indication- Large overjet
• Disadvantages :
• Difficulty in construction and
poor patient acceptance due to
complicated design.

y.com

HIGH LABIAL BOW WITH
APRON SPRINGS
• Consists of a heavy wire bow of
0.9 mm thickness into buccal
vestibule.
• Apron spring made up of 0.4
mm wire attached to the high
labial bow.
• Designed for retraction for 1 or
more teeth,being highly flexible
are thus used in cases of large
overjet .

y.com

• Apron spring is an active component that is activate by
bending it towards the teeth.
• Being flexible, activation is done up to 3 mm at a time.
• Disadvantage is Difficulty in construction and Risk of
soft tissue injuries.

y.com

FITTED LABIAL BOW :• In this type , the wire is adapted to
confirm to the contour of the labial
surface.
• U loop is usually small and cannot be used
to bring about active tooth movement.
• Used as fixed retainers at the completion
of fixed orthodontic therapy.

y.com

SPRINGS
They are active component of removable orthodontic
appliance.
CLASSIFICATION :1] Based on presence or absence of HELIX
a) Simple – without helix.
b) Compound – with helix.
2] Based on presence of LOOPS or HELIX
a) Helical spring.
b) Looped spring.
3] Based on the NATURE of stability
a) Self supported spring.
b) Supported spring.
y.com

Ideal requirements of a spring
•
•
•
•
•
•

Simple to fabricate
Easily fit.
Easy to clean
Apply force of required magnitude and direction.
Should fit into available space without discomfort to the pt.
Should not slip or dislodge when placed over a sloping tooth
surface.
• Should be strong and sturdy.
• Should remain active over a long period of time.

y.com

Factors To Be Considered In
Designing A Spring :• According to McKeag I926 ,the laws which regulate the stresses
and bending of orthodontic springs can be embodied in a formula
which describes the relationship between the length of a spring,
its thickness, the pressure which is required to deflect it, and the
amount of deflection produced.
• The formula states that Force generated is
F α D4
L3
where P is pressure exerted upon the spring,
l is the length of the spring,
t is its thickness (for a wire of round section), and
D is the deflection produced.
• Volume 1969 Jun (202 - 218): Removable appliances yesterday and
today - Adams
y.com

• DIAMETER OF WIRE

:-

Flexibility

depends upon diameter of wire used.
Thicker wire --> Decrease flexibility of spring and apply greater
force.
Doubling Diameter --> Force increases by 16 times.
Decreasing diameter  Force applied is lesser, spring remains
more flexible and active over a longer period.

y.com

LENGTH OF WIRE :Force decreased length of wire increases
Longer spring , more flexible and remain active for a
longer duration of time.
Helices and Loops incorporated in the spring make
them more active.
Doubling the length the force can be reduced by 8
times.

Force to be applied :Force that should be generated by the spring is
calculated by
Number of teeth to be moved ,Root surface area and
Patient comfort .
On average, force of about 20 gm/cm2 root area is
recommended.
y.com

PATIENT COMFORT :Spring should offer any patient discomfort by way of its
design ,size and force that it generates.
Patient should be able to insert the appliance with the
spring in the proper position so as to bring the desired
tooth movement.

DIRECTION OF TOOTH MOVEMENT
Direction of tooth movement is determined by the point of
contact between spring and tooth.
Palatally placed are used for labial and mesio-distal tooth
movement.
Buccally placed springs are used when the tooth is to be
moved palatally and in a mesio-distal direction.
y.com

FINGER SPRING :• Also called SINGLE
CANTILEVER SPRING as one
end is fixed in acrylic and other
end is free.
• Constructed in 0.5-0.6 mm hard
round S S wire.
• Used for mesio-distal movement
of teeth and can be used in teeth
that are placed correctly in buccolingual direction.

y.com

FINGER SPRING :• Finger spring consists of an active arm
of 12 – 15 mm which is towards the
tissue , a helix of 3 mm internal
diameter and a retentive arm of 4 – 5
mm length which is kept away from the
tissue and ends in small retentive tag.
• The coil lies along the long axis of tooth
to be moved, perpendicular to the
direction of movement.
• Coil is in direction opposite to that of
tooth surface.

y.com

• Prior to acrylisation,the helix and the active arm are
boxed in wax so that the spring lies in an recess
between the mucosa and base plate.
• Finger spring is activated by moving the active arm
towards the teeth intended to be moved.
• Activation of 3 mm is considered ideal,when 0.5 mm
wire is used.
• Whenever 0.6 mm of wire is used the activation should
be half of that.

y.com

Straighten
ed piece of
wire

y.com

Position the wire in the
plier

y.com

Bend the wire around the the
round beak of the plier

y.com

Turn the wire around the beak to form a
y.com

Position it on the cast

y.com

Adapt thewww.indiandentalacadem the palatal
retentive arm to
y.com

y.com

Mark the position on active arm

Bend the wire www.indiandentalacadem the
such that it engages
y.com

Z SPRING :• Also called DOUBLE
CANTILEVER SPRING.
• Used for labial movement of
incisors and bringing about minor
rotation of incisors.
• Made up of 0.5 mm hard round S
S wire.
• Springs can be made for the
movement of of a single or two
incisors.

y.com

• Spring consists of two coils of very small internal
diameter.
• It should be parallel to the palatal surface of the tooth.
• It has a Retentive arm of 10 – 12 mm length that gets
embedded in acrylic.
• Z spring is activated by opening both the helices by
about 2-3 mm at a time,incase of minor rotation
correction, one of the helices is opened.

y.com

y.com

Take a straightened piece of wire.bend one end and

Mark the

position distal contact point
y.com

on wire

Form www.indiandentalacadempoint
a Helix at that
y.com

The arms should be parallel to each other. Make
another helix at a point such that both arms are
y.com

Completed Z Spring in position
y.com

T SPRING :• The spring consist of a T shaped arm whose
ends are embedded in acrylic.
• Buccal movement of premolars and sometimes
canines can be brought about using a T spring.
• It is made of 0.5 mm hard round stainless steel
wire.
• Loops can be incorporated in both the arms of
the T so that as the tooth moves buccally. The
head of the T can be made to remain in contact
with the crown by slightly opening the loops.
• The spring is activated by pulling the free end
of the T towards the intended direction of
tooth movements.
y.com

COFFIN SPRING :• This is a removable type of arch expansion
spring that was introduced by Walter Coffin.
• It is used to bring about slow dento-alveolar
arch expansion in patients where the upper arch
is constricted or there is a unilateral cross bite.
• The Coffin spring is made of 1.2 mm hard
round stainless steel wire.
• It consists of a U or omega shaped wire placed
in the mid-palatal region with the retentive
arms incorporated into base plates.

y.com

• The appliance gains retention from Adam’s clasps on
the first molars and the first premolars or deciduous
molars.
• The Coffin spring can be activated manually by holding
both the ends at the region of the clasps and pulling
the sides gently apart.
• Activation of 1-2 mm at a time is considered
appropriate.

y.com

CANINE RETRACTORS :They are springs used to move
canines in distal direction.

CLASSIFICATION :A) Based on their LOCATION :-Buccally placed or
Lingually placed.
B) Based on the presence of HELIX or LOOP:- Canine
retractor with or without HELIX
C) Based on their MODE OF ACTION :- Push type or
Pull type.

y.com

• Mechanically it is least effective and is used when
minimal retraction of 1-2 mm is required.
• It is activated by closing the loops by 1-2 mm or
cutting the free end of the active arm by 2 mm and
readapting it.
• Advantages of this retractor are case in fabrication and
less bulk.

y.com

U LOOP CANINE RETRACTOR:•
•
•
•

It is made of 0.6 mm or 0.7 mm wire.
It consists of a U loop, an active arm
and a retentive arm which is distal.
The base of the loop should be 2-3
mm below the cervical margin.
The mesial arm of the U loop is bent
at right angles and adapted around the
canine below its mesial contact point

y.com

HELICAL CANINE RETRACTOR:• It is also called reverse loop canine
retractor and is made of 0.6 mm
wire.
• It consists of a coil of 3 mm
diameter , an active arm and a
retentive arm.
• The mesial arm is adapted between
the premolars.
• The distal arm is active and is bent at
right angles to engage the canine
below the height of contour.

y.com

• The coil is placed 3-4 mm below the gingival margin.
• It is activated by opening the helix by 2 mm or by
cutting 2 mm of the free end and readapting it around
the canine.
• It is indicated in patients with shallow sulcus.

y.com

BUCCAL SELF SUPPORTED
CANINE RETRACTOR :• It is made of 0.7 mm wire.
• It consists of a helix of 3 mm
diameter, an active arm and a
retentive arm.
• The coil is placed distal to the
long axis of canine.

y.com

• It is indicated in case of bucally placed and canines
placed high in the vestibule.
• It is called self-supported because it is made of thicker
diameter wire which can resist distortion.
• It is activated by closing the helix 1 mm at a time.

y.com

PALATAL CANINE RETRACTOR
• It is made up of 0.6 mm stainless steel wire.
• It consists of a coil of 3 mm diameter, an
active arm and guide arm.
• The active arm is placed mesial to canine.
• The helix is placed along the long axis of
canine.
• It is indicated in retraction of canines that are
palatally placed.
• Activation is done by opening the helix 2 mm
at a time.

y.com

SCREWS:• Screws are active components that can be incorporated
in a removable appliance.
• Used to bring about many types of tooth movements.
• Activated by pts at regular intervals using a key.
• They are valuable aid in pts who cannot visit dentist
frequently.
• Appliance with screws usual consist of a split acrylic
plate and Adam's clasp on posterior teeth.

y.com

• Screw is placed connecting the split acrylic plate, can
bring about various types of movements based on the
location of acrylic split,the location of screw amd
number of screw used in appliance.
• Removable appliance using screws bring about 3 types
of movements : > Expansion of arch.
> Movement of one or a group of teeth in buccal or
labial direction.
>Movement of 1 or more teeth in a distal or mesial
direction.

y.com

ELASTICS :• They are active component which are seldom used with
removable appliance.
• Mostly used in conjunction with fixed appliance.
• Appliance using elastics for anterior retraction making
use of a labial bow with hooks placed distal to the
canines.
• Disadvantages are elastics tend to slip gingivally causing
trauma and risk of arch form getting flattened.

y.com

BASE PLATES

y.com

USES OF BASE BLATES :•
•
•
•
•

Unites all components of the appliance into one unit.
Helps in anchoring the appliance in place.
Provides support for the wire components.
Helps in distributing the forces over a larger area.
Bite planes can be incorporated into the plate to treat
specific orthodontic problems.

y.com

THICKNESS OF BASE PLATE
Base plate should have minimum thickness to help in
patient acceptance.
Thick plates are less tolerated by pts.
Base plate of 1.5 – 2 mm thickness offers adequate
strength and is well tolerated by the patient.
EXTENSION OF BASE PLATE

:-

Maxillary base plate usually covers the entire palate till the distal of
the 1st molar.Full coverage helps in gaining adequate strength.
Narrow maxillary base plate resembling a horse shoe are less stable
and likely to get dislodged during movement.
Mandibular base plate is usually shallow to avoid irritation to the
lingual sulcus. To compensate for this,plate is made thicker to
increase strength.
y.com

Materials used for base plate:• COLD CURE ACRYLIC.
• HEAT CURE ACRYLIC.

y.com

Factors to be considered at the time
of delivery of removable appliance :• Tissue surface of appliance should not have any sharp
areas or nodules.
• Base plate may need some trimming to help in ease of
insertion and removal.
• Clasp should be examined for adequate
retention,should be engaged in undercut if not
retentive.
• Active components should rest at desired location.
• Patient should be educated on how to insert and
remove the appliance.
• Active components can be activated after few days
once the patient gets used to the appliance.
y.com

Instruction to the patient :• Pt instructed on number of hours of wear,to be worn
day n night.
• Appliance and teeth to be clean after every meal.
• Pt is asked to clean the appliance using detergent
solution and brush.
• In case of appliance with screws,pt and parents should
be given clear instruction on how to activate the
appliance.
• Pt instructed to report immediately to the clinic in case
of appliance damage or other problems.
• Pt instructed not to leave the appliance out of mouth
for a long period.
y.com

Problems encountered in
removable appliance therapy:•
•
•
•
•

Oral hygiene maintenance.
Soft tissue irritation.
Caries.
Pain.
Tooth mobility.

y.com

BIBILIOGRAPHY :• CONTEMPORARY ORTHODONTICS - WILLIAM R.
PROFFIT.
• THE DESIGN,CONSTRUCTION AND USE OF
REMOVABLE ORTHODONTIC APPLIANCE - C. PHILIP
ADAMS & W.JOHN.KERR.

y.com

“THANK YOU“


Removable orthodontic appliances /certified fixed orthodontic courses by Indian dental academy

Recommended

Recommended

More Related Content

More from Indian dental academy

More from Indian dental academy (20)

Recently uploaded

Recently uploaded (20)

Removable orthodontic appliances /certified fixed orthodontic courses by Indian dental academy