Removable

RemovableRemovable
OrthodonticOrthodontic
AppliancesAppliances
www.indiandentalacademy.com

 Removable orthodontic appliancesRemovable orthodontic appliances areare
those that can be inserted and removedthose that can be inserted and removed
from oral cavity by patient at will or byfrom oral cavity by patient at will or by
an orthodontist for adjustment.an orthodontist for adjustment.

Development of RemovableDevelopment of Removable
 In United States,In United States, Victor Hugo JacksonVictor Hugo Jackson was thewas the
chief proponent of removable appliance.chief proponent of removable appliance.
 Europe -Europe - Removable appliancesRemovable appliances
 U. S. -U. S. - Fixed appliancesFixed appliances
DEVELOPMENT IN EUROPEDEVELOPMENT IN EUROPE
 Angle’sAngle’s emphasis on precise positioning had less impact.emphasis on precise positioning had less impact.
 Social welfare systemsSocial welfare systems
 Precious metal for fixed less availablePrecious metal for fixed less available
 Establishment ofEstablishment of National Health ServiceNational Health Service (1948)(1948)

In European mid twentieth century removableIn European mid twentieth century removable
appliances differentiated intoappliances differentiated into
 ActivatorsActivators oror functional appliancesfunctional appliances
 Active plateActive plate
At present removable appliances are indicated forAt present removable appliances are indicated for
three major usesthree major uses::
 Growth modificationGrowth modification
 Limited (tipping) tooth movementsLimited (tipping) tooth movements
 RetentionRetention

AdvantagesAdvantages
 Can be removed on socially sensitive occasionsCan be removed on socially sensitive occasions
 Patient can maintain good oral hygiene; thePatient can maintain good oral hygiene; the
appliance can also be kept clean.appliance can also be kept clean.
 Majority of the malocclusions which requires tippingMajority of the malocclusions which requires tipping
can be readily treated.can be readily treated.
 Bite planes can be incorporated into it.Bite planes can be incorporated into it.

 Can be fabricated in laboratory utilizing less chairCan be fabricated in laboratory utilizing less chair
side timeside time
 Simple malocclusions can be treated by generalSimple malocclusions can be treated by general
practitionerpractitioner
 Relatively inexpensiveRelatively inexpensive
 Damaged appliances that apply undesirableDamaged appliances that apply undesirable
forces can be removedforces can be removed

DisadvantagesDisadvantages
 Patient co-operation is very important for thePatient co-operation is very important for the
success of treatment.success of treatment.
 Capable of only tipping movementCapable of only tipping movement
 Lower removable appliances are not wellLower removable appliances are not well
toleratedtolerated Multiple rotations are difficult to treat.Multiple rotations are difficult to treat.
 In extraction cases it is difficult to close theIn extraction cases it is difficult to close the
residual spaces.residual spaces.
 Greater chance of appliance being misplaced orGreater chance of appliance being misplaced or
damaged.damaged.

Case selectionCase selection
The patientThe patient
 Co-operative patient with good oral hygieneCo-operative patient with good oral hygiene
 Where Frankfort mandibular angle is veryWhere Frankfort mandibular angle is very
high or lowhigh or low
 Where extensive treatment of lower arch isWhere extensive treatment of lower arch is
neededneeded
 Where teeth has to be moved bodilyWhere teeth has to be moved bodily
 Where there is extensive rotationWhere there is extensive rotation
 Where soft tissue pattern is unfavorableWhere soft tissue pattern is unfavorable
OcclusionOcclusion
Do not attempt in severe Class II and Class IIIDo not attempt in severe Class II and Class III
malocclusion particularly skeletal discrepanciesmalocclusion particularly skeletal discrepancies

Classification of RemovableClassification of Removable
 Broadly classified into intra oral, extra oral, orBroadly classified into intra oral, extra oral, or
combination.combination.
 INTRA ORALINTRA ORAL
 Simple appliancesSimple appliances –– Oral Screen,Oral Screen,
Inclined planeInclined plane
 Unimaxillary plate appliancesUnimaxillary plate appliances forfor
maxilla or mandible.maxilla or mandible.
– Active plateActive plate
– Retention plateRetention plate

•Bimaxillary applianceBimaxillary appliance –– these are doublethese are double
plates with intermaxillary connection likeplates with intermaxillary connection like
activator, bionator and functional regulatoractivator, bionator and functional regulator
 EXTRA ORALEXTRA ORAL
 Chin capChin cap
 Head gearHead gear
 COMBINATIONCOMBINATION
 Maxillary appliance with face mask forMaxillary appliance with face mask for
maxillary protraction.maxillary protraction.

Active PlateActive Plate
 The removable appliance used at presentThe removable appliance used at present
were developed before World War II. At thatwere developed before World War II. At that
time there were two distinctly differenttime there were two distinctly different
devices:devices:
1.1. The active plateThe active plate – uses force within the– uses force within the
appliance.appliance.
2.2. The activatorThe activator – used muscular forces– used muscular forces..

Of Historical ImportanceOf Historical Importance
 Coffin plateCoffin plate (1881) , with spring which was(1881) , with spring which was
then made PIANO wire.then made PIANO wire.
 Norman Kingsley (1880) first described hisNorman Kingsley (1880) first described his
plate for “plate for “JUMPING THE BITEJUMPING THE BITE””
 Pierre Robin (1902) constructed the firstPierre Robin (1902) constructed the first SplitSplit
plateplate
 In England J.H Badcok (1911) describedIn England J.H Badcok (1911) described
expansion screwexpansion screw

Basic components ofBasic components of Active plateActive plate
 Active elementsActive elements - Labial bow
- Springs
- Screws
- Elastics
- Clasps
 Retentive elementsRetentive elements
 The base plateThe base plate

Labial BowsLabial Bows
Parts of labial bowParts of labial bow
11. Incisor segment. Incisor segment
22. Vertical loops. Vertical loops
3.3. Cross over sectionCross over section
4.4. Retentive armRetentive arm

Incisor segmentIncisor segment
 Usually in the junction of middle third and incisalUsually in the junction of middle third and incisal
thirdthird
 Right angle bend at the distal third of lateralRight angle bend at the distal third of lateral
incisors or mesial third of canine.incisors or mesial third of canine.
 Contacts only the most prominent teethContacts only the most prominent teeth

Vertical loopsVertical loops
 Consists of parallel vertical legs joined by aConsists of parallel vertical legs joined by a
smooth curve.smooth curve.
 Its usually 9 – 12 mm, extending 2 – 3 mmIts usually 9 – 12 mm, extending 2 – 3 mm
above the gingival margin.above the gingival margin.
 At the gingival level the loop is 1-1.5 mmAt the gingival level the loop is 1-1.5 mm
awayaway

UsesUses::
 Move teeth lingually.Move teeth lingually.
 Restraining action on lipRestraining action on lip
 Support for soldered springs, bar loops or forSupport for soldered springs, bar loops or for
hooks to attach elastic bandshooks to attach elastic bands
 Friction of labial wire against the anteriorFriction of labial wire against the anterior
teeth act as clasp to enhance the fit of theteeth act as clasp to enhance the fit of the
plate.plate.

The various types of Labial bowsThe various types of Labial bows
 Short labial bowShort labial bow
 Long labial bowLong labial bow
 Split labial bowSplit labial bow
 Reverse labial bowReverse labial bow
 Roberts retractorRoberts retractor
 Mills retractorMills retractor
 High labial bow with apron springsHigh labial bow with apron springs
 Fitted labial bowFitted labial bow

Short Labial BowShort Labial Bow
 Constructed using 0.7 mm stainless steel wire.Constructed using 0.7 mm stainless steel wire.
 Retentive arm distal to canine.Retentive arm distal to canine.
 It is very stiff and exhibits low flexibilityIt is very stiff and exhibits low flexibility
IndicationIndication
 Minor overjet reductionMinor overjet reduction
 Anterior space closure.Anterior space closure.
ActivationActivation -- compressing the “U” loops.compressing the “U” loops.www.indiandentalacademy.com

Long Labial BowLong Labial Bow
INDICATIONSINDICATIONS
 Minor anterior space closureMinor anterior space closure
 Minor overjet reductionMinor overjet reduction
 Closure of space distal to canineClosure of space distal to canine
 Guidance of canine during retractionGuidance of canine during retraction

Split Labial BowSplit Labial Bow
 Split in middle 2 separate buccal arms having U loopSplit in middle 2 separate buccal arms having U loop
 Increased flexibilityIncreased flexibility
INDICATIONSINDICATIONS
Anterior retractionAnterior retraction
Modified form for closure of midline diastemaModified form for closure of midline diastema
ACTIVATIONACTIVATION compressing U loop 1-2 mm at a timecompressing U loop 1-2 mm at a time

Reverse Labial BowReverse Labial Bow
 The U loops are placed distal to the canineThe U loops are placed distal to the canine
 Free ends of the U loop are adapted occlusallyFree ends of the U loop are adapted occlusally
between first premolar and caninebetween first premolar and canine

High labial bow with apronHigh labial bow with apron
springssprings
 Consists of a heavy wire labial bow (0.9 or 1 mm)Consists of a heavy wire labial bow (0.9 or 1 mm)
that extends into the buccal vestibulethat extends into the buccal vestibule
 Apron springs made of 0.4 mm wire are attachedApron springs made of 0.4 mm wire are attached
USESUSES
 Retraction of one or more teethRetraction of one or more teeth
 Cases of large overjet due toCases of large overjet due to
increased flexibilityincreased flexibility

ACTIVATIONACTIVATION
 Apron spring is activated by bending itApron spring is activated by bending it
towards the teeth (3 mm)towards the teeth (3 mm)
DISADVANTAGESDISADVANTAGES
 Difficulty in constructionDifficulty in construction
 Risk of soft tissue injuryRisk of soft tissue injury

Fitted Labial BowFitted Labial Bow
 Adapted to confirm to the contours of labialAdapted to confirm to the contours of labial
surfacessurfaces
 Used only as a retainerUsed only as a retainer

Roberts RetractorRoberts Retractor
 Flexible bow constructed fromFlexible bow constructed from
0.5 mm diameter wire inserted0.5 mm diameter wire inserted
into a stainless steel tubing tointo a stainless steel tubing to
give supportgive support
 Consists of a coil of 3 mmConsists of a coil of 3 mm
diameter mesial to caninediameter mesial to canine

ActivationActivation
 The bow is adjusted by bending the vertical limbThe bow is adjusted by bending the vertical limb
below the coilbelow the coil
 As the incisor moves palatally, the bow will dropAs the incisor moves palatally, the bow will drop
anteriorly and the level of horizontal part should beanteriorly and the level of horizontal part should be
adjustedadjusted
In patients with severe overjet of over 4 mmIn patients with severe overjet of over 4 mm

Mills RetractorMills Retractor
 Called as ‘extended labial bow’.Called as ‘extended labial bow’.
 Extensive looping increases the flexibilityExtensive looping increases the flexibility
 IndicatedIndicated in patients with large overjetin patients with large overjet
 DisadvantagesDisadvantages
- Difficulty in construction- Difficulty in construction
- Poor patient acceptability- Poor patient acceptabilitywww.indiandentalacademy.com

Labial wire with M loopLabial wire with M loop

Labial wire with soldered hooksLabial wire with soldered hooks

Labial wire with springsLabial wire with springs

Based on nature of stability of the springBased on nature of stability of the spring --
a.a. Self supportedSelf supported springssprings
b.b. SupportedSupported springssprings
Based on presence or absence ofBased on presence or absence of
helixhelix a.a. SimpleSimple – without helix– without helix
b.b. CompoundCompound – with– with
helixhelix
CLASSIFICATIONCLASSIFICATION
SpringsSprings

Based on presence of loops orBased on presence of loops or
helixhelix
a.a.HelicalHelical springssprings
b.b.LoopedLooped springssprings
Based on direction of forceBased on direction of force
aa.Protraction.Protraction springssprings
b.b.RetractionRetraction springssprings
c.c.PalatalPalatal springssprings
d.d.MesiodistalMesiodistal springssprings
Open
Close
d

Factors to be considered inFactors to be considered in
designing of a springdesigning of a spring
Within the elastic limit a spring may be deflected byWithin the elastic limit a spring may be deflected by
pressurepressure PP at a free end if theat a free end if the lengthlength isis LL andand
thicknessthickness isis TT thenthen deflectiondeflection DD is given byis given by
T4
D α PL3

If the thickness isIf the thickness is
reduced by halfreduced by half
deflection becomesdeflection becomes
1616 timestimes greater forgreater for
the same amount ofthe same amount of
pressurepressure
DoubleDouble the pressurethe pressure
doubledouble the deflectionthe deflection
DoublingDoubling the the lengththe the length
the deflection becomesthe deflection becomes
8 times8 times more for themore for the
same amount ofsame amount of
pressurepressure

 Diameter of wireDiameter of wire
 Length of the wireLength of the wire
FF11 LL22
FF22 LL11
 ForceForce
 DeflectionDeflection
 DirectionDirection
 LoopsLoops
=

Wire
diameter
(mm)
Number
of loops
Force
0.30.3
55 8080
33 115115
0.40.4
44 145145
33 220220
0.50.5
55 295295
44 390390
33 440440
0.60.6
55 580580
44 680680
33 810810www.indiandentalacademy.com

Pressure GaugesPressure Gauges
Plunger type of gauge
(Dontrix)

Correx pressure gauge

Single Cantilever SpringSingle Cantilever Spring
 Also called asAlso called as “finger spring“finger spring”.”.
INDICATIONSINDICATIONS::
1. Is used for the mesio-distal movement of the1. Is used for the mesio-distal movement of the
teeth.teeth.
2.2. Can be used for labialCan be used for labial
movement (crankedmovement (cranked))

PARTSPARTS
 Consists of an active arm 12 –Consists of an active arm 12 –
15 mm length towards the15 mm length towards the
tissue.tissue.
 The helix of not more than 3The helix of not more than 3
mm internal diameter.mm internal diameter.
 A retentive arm of 4 – 5 mm isA retentive arm of 4 – 5 mm is
kept away from the tissueskept away from the tissues
and ends in a small retentiveand ends in a small retentive
tag.tag.

CONSTRUCTIONCONSTRUCTION
 Constructed from 0.5 mm wireConstructed from 0.5 mm wire
 Coil should lie along the long axis of the toothCoil should lie along the long axis of the tooth
to be moved and perpendicular to theto be moved and perpendicular to the
direction of movement.direction of movement.
 Intended path of tooth movement isIntended path of tooth movement is
determineddetermined
 A line is drawn perpendicular to theA line is drawn perpendicular to the
path of the tooth movement and throughpath of the tooth movement and through
the mid crown width of the tooth.the mid crown width of the tooth.

 For maximum resilience, the coil should lie onFor maximum resilience, the coil should lie on
thethe opposite sideopposite side of the spring from the theof the spring from the the
tooth. So that it is bound up as the appliancetooth. So that it is bound up as the appliance
is inserted and unwinds as the tooth moves.is inserted and unwinds as the tooth moves.

 The finger spring is activated by moving theThe finger spring is activated by moving the
active arm towards the teeth to be moved.active arm towards the teeth to be moved.
 Should be done as close to the coil asShould be done as close to the coil as
possible.possible.
 Activation of upto 3mm is considered idealActivation of upto 3mm is considered ideal
when 0.5mm wire is used and when 0.6mmwhen 0.5mm wire is used and when 0.6mm
wire is used half of that is used.wire is used half of that is used.
 In order to protect it from damage, the spring isIn order to protect it from damage, the spring is
boxed so that it lies in the recess between theboxed so that it lies in the recess between the
base plate and mucosa.base plate and mucosa.

Double Cantilever SpringDouble Cantilever Spring
 Also known as “Also known as “Z – SpringZ – Spring””
INDICATIONINDICATION
 Labial movement of singleLabial movement of single
incisors or bothincisors or both
 To bring about minor rotationsTo bring about minor rotations

 CONSTRUCTIONCONSTRUCTION
1.1. From 0.5 mm hard roundFrom 0.5 mm hard round
stainless steel wirestainless steel wire
2.2. Spring consists of 2 coilsSpring consists of 2 coils
very small in diametervery small in diameter
3.3. Spring should beSpring should be
perpendicular to palatalperpendicular to palatal
surface of the toothsurface of the tooth
otherwise ,it tends to slideotherwise ,it tends to slide
down and intrude it.down and intrude it.

4.4. Retentive arm of 10 – 12 mm lengthRetentive arm of 10 – 12 mm length
that gets embedded into acrylicthat gets embedded into acrylic
5.5. Should be boxed prior to acrylization.Should be boxed prior to acrylization.
 ACTIVATIONACTIVATION
By opening both the helixes by aboutBy opening both the helixes by about
2 – 3 mm at a time .In case of minor2 – 3 mm at a time .In case of minor
rotation one of the helix is opened.rotation one of the helix is opened.

T SpringT Spring
When a premolar or a canineWhen a premolar or a canine
has to be moved buccallyhas to be moved buccally
ConstructionConstruction
 Made of 0.5 mm hard roundMade of 0.5 mm hard round
stainless steel wirestainless steel wire
 Spring consists of a T shapedSpring consists of a T shaped
arm whose ends arearm whose ends are
embedded in acrylicembedded in acrylic

Coffin springCoffin spring
Introduced byIntroduced by WALTER COFFINWALTER COFFIN
 Removable type of expansion springRemovable type of expansion spring
 IndicationIndication
Used to bring aboutUsed to bring about slow transverseslow transverse
dentoalveolar arch expansiondentoalveolar arch expansion in case ofin case of
unilateral cross biteunilateral cross bite

ConstructionConstruction
 Made of 1.25 mm hard stainlessMade of 1.25 mm hard stainless
steel wiresteel wire
 Consists of aConsists of a UU or aor a OMEGAOMEGA
shaped wire placed in the midshaped wire placed in the mid
palatal region with retentivepalatal region with retentive
arms incorporated in the basearms incorporated in the base
plateplate
 Appliance gets retention fromAppliance gets retention from
adams clasp on molars andadams clasp on molars and
premolarspremolars

 ActivationActivation
Four registration points are drilled at theFour registration points are drilled at the
extremities of base plate for recording theextremities of base plate for recording the
amount of expansion by divideramount of expansion by divider

 By pulling the sides apart manually, first in theBy pulling the sides apart manually, first in the
premolar region and then in the molar regionpremolar region and then in the molar region
 Activation of 1-2 mm at a time appropriateActivation of 1-2 mm at a time appropriate

Whip applianceWhip appliance
 Rotation of a canine canRotation of a canine can
be accomplishedbe accomplished
 0.35 mm wire is attached0.35 mm wire is attached
to a bracket on a canineto a bracket on a canine
bandband
 The flexible spring isThe flexible spring is
hooked under the labialhooked under the labial
bow and produces a verybow and produces a very
gentle rotation forcegentle rotation force

Paddle springPaddle spring
 ByBy SchwarzSchwarz
 Shape of a hair pin made of 0.5 mm wire bentShape of a hair pin made of 0.5 mm wire bent
to form a paddleto form a paddle
 Activated by bending it towards the toothActivated by bending it towards the tooth

Closed protrusion springsClosed protrusion springs
 Both the ends of theBoth the ends of the
springs are embeddedsprings are embedded
in acrylicin acrylic
 Made of thinner wiresMade of thinner wires
0.4 mm0.4 mm
 Activation produces aActivation produces a
typical alteration in itstypical alteration in its
shape – moreshape – more
pronounced curvaturepronounced curvature

U loop canine retractorsU loop canine retractors
 Made of 0.6 or 0.7 mm wire.Made of 0.6 or 0.7 mm wire.
 Consists of U loop, active armConsists of U loop, active arm
and a retentive arm.and a retentive arm.
 Mesial arm of the U loop isMesial arm of the U loop is
bent at right angles andbent at right angles and
adapted around canine belowadapted around canine below
its contact pointits contact point
 U loop should be 2-3 mm below the cervical marginU loop should be 2-3 mm below the cervical margin

 UsedUsed when minimal retraction of 1-2 mm iswhen minimal retraction of 1-2 mm is
requiredrequired
By closing the loops by 1-2 mm or cutting the freeBy closing the loops by 1-2 mm or cutting the free
end of active arm by 2 mm and readapting itend of active arm by 2 mm and readapting it

Palatal canine retractorPalatal canine retractor
 Made of 0.6 mm wireMade of 0.6 mm wire
 Consists of a coil of 3 mmConsists of a coil of 3 mm
active arm, retentive armactive arm, retentive arm
 Helix is placed along the longHelix is placed along the long
axis of the canine.axis of the canine.
 INDICATEDINDICATED in retraction of palatally placed caninein retraction of palatally placed canine
 ACTIVATIONACTIVATION by opening the helix 2 mm at a timeby opening the helix 2 mm at a time

Reverse loop buccal retractorReverse loop buccal retractor
 Also called asAlso called as Helical canine retractorHelical canine retractor
 Favored when the sulcus is shallow as inFavored when the sulcus is shallow as in
case of lower achcase of lower ach
 Made of 0.6 mm wire ,consists of 3 mmMade of 0.6 mm wire ,consists of 3 mm
diameter coil ,an active arm (towards thediameter coil ,an active arm (towards the
tissue) and a retentive arm.tissue) and a retentive arm.

 Mesial arm is adaptedMesial arm is adapted
between the premolarsbetween the premolars
 The distal arm is activeThe distal arm is active
bent at right angles tobent at right angles to
engage canine below theengage canine below the
height of contourheight of contour
 Coil is placed 3 mm belowCoil is placed 3 mm below
the gingival marginthe gingival margin

 Should not be activated more than 2 mmShould not be activated more than 2 mm
 Done by cutting off 1 mm from free end andDone by cutting off 1 mm from free end and
readptingreadpting
 Alternatively done by opening the helix by 1 mm.Alternatively done by opening the helix by 1 mm.

Buccal self supported canineBuccal self supported canine
retractorretractor
 Constructed of 0.7 mm wireConstructed of 0.7 mm wire
 CalledCalled self supportedself supported because it is made ofbecause it is made of
thicker diameter wire that resists distortionthicker diameter wire that resists distortion
 Consists of helix of 3mm in diameter,anConsists of helix of 3mm in diameter,an
active arm and a retentive armactive arm and a retentive arm

 Coil lies just distal to the longCoil lies just distal to the long
axis of toothaxis of tooth
 Anterior limb passes downAnterior limb passes down
from the coil to the middle offrom the coil to the middle of
the crown and passes aroundthe crown and passes around
the mesial contact areathe mesial contact area

 UsedUsed in case of a buccaly placed canine or inin case of a buccaly placed canine or in
case of a canine placed high in vestibulecase of a canine placed high in vestibule
FeaturesFeatures
 Only spring activated by closing the the coilOnly spring activated by closing the the coil
 The active arm is away from tissues to avoidThe active arm is away from tissues to avoid
impingement of soft tissues while the coil liesimpingement of soft tissues while the coil lies
towards the tissuestowards the tissues
By closing the helixBy closing the helix

ElasticsElastics
 Its use was first described byIts use was first described by Jackson.Jackson.
 May be used for movement of single teeth orMay be used for movement of single teeth or
group of teeth and for intermaxillary traction.group of teeth and for intermaxillary traction.
 Their application was greatly enhanced byTheir application was greatly enhanced by
introduction of arrow head clasps andintroduction of arrow head clasps and
modifications of adams clasp.modifications of adams clasp.

 Intermaxillary elastics with removable plates canIntermaxillary elastics with removable plates can
be used for the treatment of Class II and Class IIIbe used for the treatment of Class II and Class III

 Slip gingivally and cause traumaSlip gingivally and cause trauma
 Risk of the arch form getting flattenedRisk of the arch form getting flattened
 Continuous immersion in saliva causes aContinuous immersion in saliva causes a
rapid force decay of elasticrapid force decay of elastic

Orthodontic ScrewsOrthodontic Screws
 Orthodontic screw is a active component of aOrthodontic screw is a active component of a
removable appliance that together with acrylicremovable appliance that together with acrylic
plates can affect the teeth and alveolar processplates can affect the teeth and alveolar process
 Screws were first introduced byScrews were first introduced by Schwarz.Schwarz.
According toAccording to HAYNESHAYNES andand JACKSON (1962)JACKSON (1962)
FEATURES of SCREWFEATURES of SCREW
 Adequate travelAdequate travel
 StabilityStability
 Minimum bulkMinimum bulk www.indiandentalacademy.com

PartsParts
 Expansion screw consists ofExpansion screw consists of
a central body which isa central body which is
generally divided into twogenerally divided into two
partsparts
 The central boss portion isThe central boss portion is
drilled with 4 holes whichdrilled with 4 holes which
are equidistant so that theare equidistant so that the
screw can be opened withscrew can be opened with
the help of a key by athe help of a key by a
quarter turn each timequarter turn each time

 The screw when turned 90The screw when turned 90
degrees will drive the partsdegrees will drive the parts
of the plate 0.2 mm apart,of the plate 0.2 mm apart,
which means narrowing ofwhich means narrowing of
the periodontal membranethe periodontal membrane
0.1 mm on each side0.1 mm on each side
 Each guide pin is receivedEach guide pin is received
into the hole drilled into theinto the hole drilled into the
opposing half of theopposing half of the
expansion screwexpansion screw

 Guide pins helps in stabilizing the applianceGuide pins helps in stabilizing the appliance
precise parallel movement, prevents the endprecise parallel movement, prevents the end
plate from rotating, accidental recoilplate from rotating, accidental recoil

 The length of the screw determines theThe length of the screw determines the
maximum openingmaximum opening
 The threaded cylinder and guide pins can beThe threaded cylinder and guide pins can be
entirely encased by housing or partlyentirely encased by housing or partly
 The out side of the housing has grooves andThe out side of the housing has grooves and
undercuts for retention in acrylicundercuts for retention in acrylic

Principle of screw expansionPrinciple of screw expansion
 Pitch of screwPitch of screw
 The two screw portionThe two screw portion
on either side of theon either side of the
central boss portioncentral boss portion
are threaded inare threaded in
opposite directionopposite direction

 Expansion is brought about by displacementExpansion is brought about by displacement
of teeth within the limits of the periodontalof teeth within the limits of the periodontal
ligamentligament
 The screw is designed in such a way thatThe screw is designed in such a way that
when opened by a quarter turn, it is less thanwhen opened by a quarter turn, it is less than
the total with of the periodontal ligament (0.15the total with of the periodontal ligament (0.15
–0.35 mm)–0.35 mm)
 The intermittent forces allows remodelingThe intermittent forces allows remodeling
changes to take placechanges to take place

 Many types of tooth movement possibleMany types of tooth movement possible
 Activation within physiological limits ; lessActivation within physiological limits ; less
hyalinisationhyalinisation
 Activation precisely controlled ;simpleActivation precisely controlled ;simple
 Apply large intermittent force whichApply large intermittent force which
decreases as the teeth movesdecreases as the teeth moves

 BulkyBulky
 ExpensiveExpensive
 Turns back (recoil) under loadTurns back (recoil) under load
 Patient cooperationPatient cooperation

``Placement of screwPlacement of screw
 Transverse expansion screw should be positionedTransverse expansion screw should be positioned
in the midline,oriented to median raphein the midline,oriented to median raphe
 It lies on an imaginary line passing between firstIt lies on an imaginary line passing between first
and second premolar but in a narrow and longand second premolar but in a narrow and long
arch it is placed more posteriorlyarch it is placed more posteriorly

 The horizontal plane of the screw is placedThe horizontal plane of the screw is placed
parallel to plane of the palateparallel to plane of the palate

Special purpose screwsSpecial purpose screws
Skeleton type of screwsSkeleton type of screws
 Available inAvailable in various sizesvarious sizes – broader for– broader for
maxillary and narrower for mandibularmaxillary and narrower for mandibular

 For movement of a section of plate in case ofFor movement of a section of plate in case of
limited spacelimited space

 For extensiveFor extensive distal movementdistal movement upto 8upto 8 mmmm
designed bydesigned by WiseWise

 Designed byDesigned by HausserHausser
 A complete turn of theA complete turn of the
screw will expand it by 0.7screw will expand it by 0.7
mm ;that means a quartermm ;that means a quarter
turn on each side is lessturn on each side is less
than 0.1 mmthan 0.1 mm
 By incorporating a springBy incorporating a spring
this limited pressure can bethis limited pressure can be
kept constantkept constant
Encased screw with incorporated springEncased screw with incorporated spring

Encased pull screwEncased pull screw
 This type of screw is inserted open andThis type of screw is inserted open and
closed to effect tooth movementclosed to effect tooth movement
 In case of closure of extraction spacesIn case of closure of extraction spaces

Screws incorporated with springs for movementScrews incorporated with springs for movement
of single teethof single teeth

Spring loaded piston screwSpring loaded piston screw

 The Bertoni screw for expansion inThe Bertoni screw for expansion in
three directionthree direction

Fan type expansion screw orFan type expansion screw or
pivot screwpivot screw
 Used when anterior segment ofUsed when anterior segment of
the maxillary arch requires morethe maxillary arch requires more
expansion than posteriorexpansion than posterior
segmentsegment
 Screw is made of two parts,aScrew is made of two parts,a
hinge and a special screwhinge and a special screw
permitting a slight rotation insidepermitting a slight rotation inside
the diskthe disk

Eccentric mandibular expansion screwEccentric mandibular expansion screw
byby G. MullerG. Muller (1962)(1962)

Molar tipping screwMolar tipping screw

Hellar screwHellar screw

Anterior expansion ofAnterior expansion of
archesarches
 To correct maxillary anteriorTo correct maxillary anterior
cross bitecross bite
 Bring the base plate materialBring the base plate material
up the occlusal surface ofup the occlusal surface of
the posterior teeth, tothe posterior teeth, to
separate the teeth verticallyseparate the teeth vertically
and allow clearance forand allow clearance for
upper incisors to move out ofupper incisors to move out of
crossbitecrossbite

Transverse expansionTransverse expansion
of archesof arches
 In case of constrictedIn case of constricted
maxillary archmaxillary arch
 Active plate is split inActive plate is split in
the midline will expandthe midline will expand
the arch almost totallythe arch almost totally
by tipping the posteriorby tipping the posterior
teeth buccally and notteeth buccally and not
by opening mid palatalby opening mid palatal
suturesuture

Simultaneous Anterior andSimultaneous Anterior and
Posterior archPosterior arch
expansionexpansion
 It is possible to expandIt is possible to expand
particularly in the maxillaryparticularly in the maxillary
arch by dividing the basearch by dividing the base
plate into 3 rather than 2plate into 3 rather than 2
segments.segments.
 This is based on Schwarz’sThis is based on Schwarz’s
original Y plate usedoriginal Y plate used
simultaneously to expandsimultaneously to expand
the maxillary posterior teeththe maxillary posterior teeth
laterally and incisorslaterally and incisors
anteriorly.anteriorly. www.indiandentalacademy.com

ClaspsClasps
 These are retentive components that resistsThese are retentive components that resists
the displacement orthodontic appliance bythe displacement orthodontic appliance by
contacting the surface of the tooth or bycontacting the surface of the tooth or by
engaging the undercutsengaging the undercuts
 Clasps can be broadlyClasps can be broadly classifiedclassified intointo
Single arm claspsSingle arm clasps – C , triangular clasps– C , triangular clasps
Double arm claspsDouble arm clasps –U , Adams clasps–U , Adams clasps

Mode of actionMode of action
 They act by engaging the constrictedThey act by engaging the constricted
areas of teeth called undercutsareas of teeth called undercuts
 Two typesTwo types
1.1. Buccal and lingual cervicalBuccal and lingual cervical
undercutsundercuts
- C and U clasps- C and U clasps
2.2. Mesial and distal proximalMesial and distal proximal
undercutsundercuts
- Adams and Crozat clasps- Adams and Crozat clasps

Circumferential claspCircumferential clasp
 Also called asAlso called as C claspC clasp oror ThreeThree
quarter claspquarter clasp
 It engages the bucco cervicalIt engages the bucco cervical
undercutundercut
 Wire is engaged from one proximalWire is engaged from one proximal
undercut along the cervical marginundercut along the cervical margin
then carried over the occlusalthen carried over the occlusal
margin to end as a single retentivemargin to end as a single retentive
tag on the lingual sidetag on the lingual side

 Simplicity in design and fabricationSimplicity in design and fabrication
 Cannot be used in partially erupted teethCannot be used in partially erupted teeth
 Its made of thicker wire hence very rigidIts made of thicker wire hence very rigid

Jackson's claspJackson's clasp
 Introduced byIntroduced by JacksonJackson in 1906in 1906
 Also called asAlso called as Full claspFull clasp oror
U claspU clasp
 Engages bucco cervicalEngages bucco cervical
undercut and mesio distalundercut and mesio distal
undercutsundercuts

 Easy to construct and adequate retentionEasy to construct and adequate retention
 Inadequate retention in partially erupted teethInadequate retention in partially erupted teeth

Crozat claspCrozat clasp
 It resembles a full clasp but has a additionalIt resembles a full clasp but has a additional
piece of wire soldered which engages into thepiece of wire soldered which engages into the
mesial and distal proximal undercutmesial and distal proximal undercut
 Offers better retention than full claspOffers better retention than full clasp

Triangular claspTriangular clasp
 Introduced byIntroduced by ZimmerZimmer in 1949in 1949
 Used between two adjacentUsed between two adjacent
posterior teethposterior teeth
 Engage the proximal undercutsEngage the proximal undercuts
 IndicatedIndicated when additionalwhen additional
retention is neededretention is needed

 The triangle as a rule fits horizontally into theThe triangle as a rule fits horizontally into the
interdental spaceinterdental space
 The open end is towards the teethThe open end is towards the teeth

Southend claspSouthend clasp
 Used when retention isUsed when retention is
needed in anterior regionneeded in anterior region
 Wire adapted along theWire adapted along the
cervical margins of bothcervical margins of both
the central incisorsthe central incisors
 Distal ends are carriedDistal ends are carried
over the occlusalover the occlusal
embrasures on theembrasures on the
palatal side as retentivepalatal side as retentive
armsarms

Ball End claspBall End clasp
 Fabricated using wires having ball likeFabricated using wires having ball like
structure at one endstructure at one end
 The ball can be made at the end of theThe ball can be made at the end of the
wire using a silver solderwire using a silver solder
 Preformed wires having ball at one endPreformed wires having ball at one end
is also availableis also available

 The ball engages the proximal undercutThe ball engages the proximal undercut
between two posterior teethbetween two posterior teeth
 Indicated when additional retention isIndicated when additional retention is
requiredrequired

Arrow pin claspArrow pin clasp
 A solid arrow is bent to engage interdental spaceA solid arrow is bent to engage interdental space

Eyelet claspEyelet clasp
 Can be single , double orCan be single , double or
continuouscontinuous
 Eyelet formed withoutEyelet formed without
sharp bends so breakagesharp bends so breakage
is unlikely.is unlikely.

Duyzing’s claspDuyzing’s clasp
 Made by two wires emerging fromMade by two wires emerging from
the plate to cross the occlusionthe plate to cross the occlusion
over the anterior and posteriorover the anterior and posterior
contact point of the tooth claspedcontact point of the tooth clasped
 Then each wire goes above theThen each wire goes above the
greatest circumference of thegreatest circumference of the
tooth to the middle of the toothtooth to the middle of the tooth
and back again below using theand back again below using the
undercutundercut

Delta claspDelta clasp
 W. J Clark (1985)W. J Clark (1985)
 Retention of twin block applianceRetention of twin block appliance
 Modification of Adams claspModification of Adams clasp
 Retentive loops are in shape of closed triangleRetentive loops are in shape of closed triangle
ADVANTAGEADVANTAGE
 Does not open with repeated insertion andDoes not open with repeated insertion and
removalremoval

Arrow head claspArrow head clasp
 ByBy A. M. SchwarzA. M. Schwarz
PartsParts
1.1. The arrow head portionThe arrow head portion
2.2. Vestibular portionVestibular portion
3.3. Retentive armsRetentive arms

 The arrow heads bent in horizontalThe arrow heads bent in horizontal
plane perpendicular to long axisplane perpendicular to long axis
engage the interproximal undercutsengage the interproximal undercuts
 The vestibular portion stands 1 mmThe vestibular portion stands 1 mm
away from the tissuesaway from the tissues

 Stahl (1958)Stahl (1958) – arm– arm
should make a sweepingshould make a sweeping
curve from the base ofcurve from the base of
arrowhead to its insertionarrowhead to its insertion

PliersPliers

 The expanse of wire between the arrow headThe expanse of wire between the arrow head
makes it more elasticmakes it more elastic
 The possibility of adjusting the arrows slightlyThe possibility of adjusting the arrows slightly
mesially or distallymesially or distally
 Used both on deciduous or permanent teethUsed both on deciduous or permanent teeth
 Facilitates teeth to erupt in positionFacilitates teeth to erupt in position

 Needs a special type of pliersNeeds a special type of pliers
 Occupies a large amount of spaceOccupies a large amount of space
 Arrow heads can injure the interdental softArrow heads can injure the interdental soft
tissuestissues
 Difficult and time consuming to fabricateDifficult and time consuming to fabricate

Adams claspAdams clasp
 Described byDescribed by Philip AdamPhilip Adam
 Also known as Liverpool clasp,universal claspAlso known as Liverpool clasp,universal clasp
and modified arrow head claspand modified arrow head clasp
 Constructed using 0.7 mm hard stainlessConstructed using 0.7 mm hard stainless
steel wiresteel wire
 PartsParts
-- Two arrow headsTwo arrow heads
- The bridge- The bridge
- Two retentive arms- Two retentive arms

 The two arrowheads engage the mesial andThe two arrowheads engage the mesial and
the distal proximal undercuts.the distal proximal undercuts.
 The arrowheads are connected to each otherThe arrowheads are connected to each other
by a bridge which is at a 45by a bridge which is at a 45° to the long axis° to the long axis
of the tooth.of the tooth.
 Corrected constructed Adams clasp shouldCorrected constructed Adams clasp should
be passive but in contact with tooth surfacebe passive but in contact with tooth surface
when the appliance is fully insertedwhen the appliance is fully inserted

 It is rigid and offers excellent retention.It is rigid and offers excellent retention.
 Can be fabricated on both deciduous andCan be fabricated on both deciduous and
permanent dentition.permanent dentition.
 Can be used on partially or fully erupted teeth.Can be used on partially or fully erupted teeth.
 Can be used on molars, premolars and incisors.Can be used on molars, premolars and incisors.
 No specialized instruments needed to fabricate.No specialized instruments needed to fabricate.
 It is small and occupies minimum space.It is small and occupies minimum space.
 Clasp can be modified in a number of waysClasp can be modified in a number of ways

Essential features of Adam’s claspEssential features of Adam’s clasp
 Bridge is straight.Bridge is straight.
 Arrowheads are parallel and must not contactArrowheads are parallel and must not contact
adjacent tooth.adjacent tooth.
 Bridge stands away from tooth at an angle ofBridge stands away from tooth at an angle of
45.45.

 Tags are formed by turning down at rightTags are formed by turning down at right
angles.angles.
 The clasp should be passive but in contactThe clasp should be passive but in contact
with the teeth when fully inverted.with the teeth when fully inverted.
 Should not exert any force as it can tip theShould not exert any force as it can tip the
tooth.tooth. www.indiandentalacademy.com

ModificationsModifications
Adam with single arrow headAdam with single arrow head
 Indicated in a partially erupted tooth usually the lastIndicated in a partially erupted tooth usually the last
erupted molarerupted molar
 Arrow head is made to engageArrow head is made to engage the mesio proximalthe mesio proximal
undercut of the last erupted molarundercut of the last erupted molar
 Bridge is modified to encircle the tooth distally andBridge is modified to encircle the tooth distally and
ends on the palatal aspect as a retentive armends on the palatal aspect as a retentive arm

Adam with J hookAdam with J hook
Adam with incorporatedAdam with incorporated
helixhelix

Adam with solderedAdam with soldered
buccal tubebuccal tube
 This permits the use ofThis permits the use of
extraoral anchorage usingextraoral anchorage using
face bow - head gearface bow - head gear
assemblyassembly

 Adam with distal extensionAdam with distal extension
 Adam on incisors and premolarsAdam on incisors and premolars

Adam with additionalAdam with additional
arrowheadarrowhead
 The additional arrowheadThe additional arrowhead
engages the proximal undercutengages the proximal undercut
of the adjacent tooth and isof the adjacent tooth and is
soldered on to the bridgesoldered on to the bridge
 This offers additional retentionThis offers additional retention

 Made in the usual way, theMade in the usual way, the
bridge of the clasp should be inbridge of the clasp should be in
line with the buccal segmentline with the buccal segment
and not with the buccal surfaceand not with the buccal surface
of the tooth.of the tooth.
Adam’s clasp on rotated teethAdam’s clasp on rotated teeth

Base plateBase plate
 The frame work of the removable applianceThe frame work of the removable appliance
FunctionsFunctions
 Unites all components of the appliance intoUnites all components of the appliance into
one unitone unit
 Helps in anchoringHelps in anchoring
 Provides support for wire componentsProvides support for wire components
 Helps in distributing the forces over a largeHelps in distributing the forces over a large
areaarea
 Bite planes can be incorporatedBite planes can be incorporated

ExtensionExtension
 The maxillary base plateThe maxillary base plate
usually covers the entireusually covers the entire
palate till the distal of thepalate till the distal of the
first molar.first molar.
THICKNESSTHICKNESS
 Base plates of 1.5 –2 mm thickness offerBase plates of 1.5 –2 mm thickness offer
adequate strength and at the same time welladequate strength and at the same time well
tolerated.tolerated.

 The mandibular base plate is UThe mandibular base plate is U
shapedshaped
 It is usually shallow to avoidIt is usually shallow to avoid
irritation to lingual sulcusirritation to lingual sulcus
thereby a reduction in strengththereby a reduction in strength
 To compensate for this it shouldTo compensate for this it should
be reinforced with a stainlessbe reinforced with a stainless
wirewire

Materials usedMaterials used
Heat cureHeat cure
 More color stabilityMore color stability
 Less porosityLess porosity
 StrengthStrength
Self cureSelf cure
 ConvenienceConvenience
 SpeedSpeed
 CostCost
 Possible for repairPossible for repair

Heat cureHeat cure
StepsSteps
 Wire parts of the appliance secured to theWire parts of the appliance secured to the
cast by pink wax.cast by pink wax.
 Cast dipped in water for 10 – 15 minutesCast dipped in water for 10 – 15 minutes
and the surface wetness allowed to dry.and the surface wetness allowed to dry.

 Single sheet of wax isSingle sheet of wax is
warmed and pressedwarmed and pressed
over cast.over cast.
 Wax is trimmed to shapeWax is trimmed to shape
with a double flat endedwith a double flat ended
instrument.instrument.
 Any wax inside or aboutAny wax inside or about
the coil of the spring isthe coil of the spring is
removed with a probe.removed with a probe.

 While flasking care should be taken to putWhile flasking care should be taken to put
plaster around the springs and in the coil.plaster around the springs and in the coil.
 When processed the appliance is deflasked,When processed the appliance is deflasked,
plaster removed and the plate is trimmed andplaster removed and the plate is trimmed and
polished.polished.

Self cureSelf cure
StepsSteps
 The cast is coated with separating medium.The cast is coated with separating medium.
 All the components are secured in position usingAll the components are secured in position using
pink wax.pink wax.
 Parts of the springs which must not be bound up inParts of the springs which must not be bound up in
the base plate material are covered with pink wax.the base plate material are covered with pink wax.

 Self cure acrylic is applied –Self cure acrylic is applied –
- single mix technique- single mix technique
- salt and pepper/sprinkle on technique- salt and pepper/sprinkle on technique
 Appliance trimmed and polished.Appliance trimmed and polished.www.indiandentalacademy.com

Clear acrylic resinsClear acrylic resins
AdvantageAdvantage
Blanching of the tissues can be seen.Blanching of the tissues can be seen.
Any entrapment of food can be observed.Any entrapment of food can be observed.
Base plate can also be fabricated usingBase plate can also be fabricated using
thermoplastic acrylic sheets which are warmed onthermoplastic acrylic sheets which are warmed on
aa BiostarBiostar machine (220machine (220° C), the advantage being° C), the advantage being
uniform thickness.uniform thickness.

Delivery of the applianceDelivery of the appliance
 Check that the previously described designCheck that the previously described design
has been made correctly.has been made correctly.
 Check for any roughnessCheck for any roughness
 Trimming acrylic base for proper fitTrimming acrylic base for proper fit
 Adjust springsAdjust springs
 Test the functioning of screws.Test the functioning of screws.
 Examination of claspsExamination of clasps
 No soft tissue impingementNo soft tissue impingement

InstructionsInstructions
 Insertion & removal.Insertion & removal.
 DurationDuration
 CleaningCleaning
 Activation of screwsActivation of screws
 Report to clinic in case of any damageReport to clinic in case of any damage

The advantage of removable orthodontic appliance is that
it can be taken out. The user must take it out and clean
it thoroughly to remove the dental plaque in the
morning and before bed at night.
Take out the removable orthodontic
appliance, use a toothbrush and some
liquid soap to clean every surface of the
appliance. After cleaning, the appliance
can be worn again.
When the orthodontic
appliance is not worn, it should
be cleaned and immersed in a
cup of water.
dental plaque

Examination at each return visitExamination at each return visit
 Enquire if the appliance has beenEnquire if the appliance has been
comfortable.comfortable.
 Patient asked to remove & insert thePatient asked to remove & insert the
applianceappliance
 Check for any facets ,wear upon acrylic &Check for any facets ,wear upon acrylic &
even breakage.even breakage.

 Amount of tooth movementAmount of tooth movement
 Soft tissueSoft tissue
 Reschedule the next appointment - 4Reschedule the next appointment - 4
weeks interval.weeks interval.

DeclineDecline
 Since 1970 decline in U KSince 1970 decline in U K
 Series of technical advancesSeries of technical advances
ORTHODONTIC BANDSBANDS
PreweldedPrewelded Preforme
d
DIRECT BONDED ATTACHMENTSDIRECT BONDED ATTACHMENTS
PREADJUSTED EDGEWISEPREADJUSTED EDGEWISE

According toAccording to BDJ sept 22 2001 vol 191BDJ sept 22 2001 vol 191
 Quality not so highQuality not so high
 Higher discontinuation of treatmentHigher discontinuation of treatment
 Few general practioners willing to undertakeFew general practioners willing to undertake
orthodontic treatmentorthodontic treatment
 Malocclusion requiring tipping are fewMalocclusion requiring tipping are few
 Only in certain limited cases they provideOnly in certain limited cases they provide
simple , effective, efficient treatmentsimple , effective, efficient treatment

ConclusionConclusion
It is emphasized that if good results are to beIt is emphasized that if good results are to be
obtained meticulous attention must be paid toobtained meticulous attention must be paid to
case history, treatment planning, appliancecase history, treatment planning, appliance
design and adjustment.design and adjustment.
Although removable appliances are adequate toAlthough removable appliances are adequate to
produce majority of tooth movements, it isproduce majority of tooth movements, it is
difficult to attain the precision of fixed appliance.difficult to attain the precision of fixed appliance.

BibliographyBibliography
 Removable appliance fabrication :Removable appliance fabrication :
Witt ,Shaye and GehrkeWitt ,Shaye and Gehrke
 Removable Orthodontic appliances :Removable Orthodontic appliances :
Graber and NeumannGraber and Neumann
 Orthodontic treatment with RemovableOrthodontic treatment with Removable
appliances :appliances : Houston and IsaacsonHouston and Isaacson
 The Design Construction Use Of RemovableThe Design Construction Use Of Removable
Orthodontic Appliances :Orthodontic Appliances :C.Philip AdamsC.Philip Adams
 Contemporary Orthodontics :Contemporary Orthodontics : ProfittProfitt

THANK YOU…THANK YOU…

Removable

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