describes about orthodontic removable appliances

2. Introduction
 Removable orthodontic ppliances are the orthodontic
appliances that can be inserted into and removed from
oral cavity by patient

3. Advantages Disadvantages
1.Tipping movement
2.Can be removed -for cleaning of teeth
& appliance -if in pain -on socially
sensitive occasion
3.Less conspicuous
4.Can be undertaken by general
practitioner with adequate training
5.Manufactured in lab -less chair side
time -more patients can be treated
6.Inexpensive
1.Only simple malocclusion can be
corrected
2.Multiple rotations cannot be corrected
3.Uncooperative patients may leave out
the applianceprolongs treatment
4.Multiple tooth movement - one at a
time- prolongs Rx duration
5.Lower appliance not well tolerated
6.Cases other than I premolar extraction
cannot be treated easily

4. Indications
 Growth modifications during mixed dentition.
 Limited tipping, rotation required.
 Arch expansion.
 Retention after fixed treatment.

5. Components of removable
appliances
 Retentive Components
 Base plate
 Active components

6. Retentive components
 Clasps

7. Active components
 Labial bow
 Springs
 Screws
 Elastics

8. CLASPS
 Clasps are the retentive components of the
orthodontic appliances.

9. IDEAL REQUIREMENTS
 Unobtrusive.
 Not impinge.
 Close contact to the tooth.
 Usable in both deciduous and permanent dentition.
 Adequate retention.
 No active force on the anchor tooth.
 Rigid
 Easy to fabricate and also replace if needed.
 Not interfere in the growth of jaws and eruption of
teeth.

10. Uses
 To secure the appliance in position
 To prevent rolling of appliances
 To resist forces of displacement
 To provide retention & anchorage
 For engaging elastic

11. MODE OF ACTION
 Clasp engage onto the undercuts (constricted areas on
the teeth.) •
 Two types of undercuts.
 – Buccal / Lingual Cervical undercuts.
 – Mesial / Distal Proximal undercuts.

12. Circumferential clasp
 Fabricated using wire 0.9mm
 Also known as ‘C’ clasp or Three Quarter Clasp
 Simple clasp used to engage buccocervical undercut
 Cannot be used in partially erupted teeth

13. Jackson’s Clasp
 V.H. Jackson 1906
 Fabricated using 0.9mm wire
 Also known as Full clasp or ‘U’ clasp
 Engages both buccocervical undercuts
 Simple design
 Offers adequate retention
 Inadequate retention in partially erupted teeth

14. Southened clasp
 .7 mm wire
 spans two adjacent margins of anterior teeth
 Esthetically more pleasing

15. Triangular Clasp
 Fabricated using 0.6mm wire
 used between adjacent posterior teeth
 Indicated for additional retention

16. Ball end clasp
 Wire having a knob or ball like structure on one end
 utilizes interdental undercuts
 Indicated when additional retention required

17. Delta clasp
 Designed by William J. Clark
 Similar to Adams clasp in principle
 Retentive loops were triangular in shape hence the
name
 Engage interdental undercuts
 USED IN TWIN BLOCK APPLIANCES

18. Advantages
 Design of the closed loop does not open up with
repeated removal.
 Less subject to breakage.
 Provides excellent retention on lower premolars.
 Suitable for use on most posterior teeth.

19. Crozat clasp
 Crozat in 1920
 Along with the u clasp a stright wire is soldered on the
base (Cresent).
 Strong retention is possible

20. Schwarz clasp
 Also called as arrow head clasp
 A.M.Schwarz 1935
 Mesial and distal undercuts of the teeth

21. Adam’s Clasp
 Also known as Liverpool Clasp, Universal Clasp,
Modified Arrowhead Clasp
 Parts
 Bridge
 Arrowhead
 Retentive arms

22. Adam’s Clasp
 C. PHILIPS ADAMS in May 1950
 Most widely used clasp.
 Distobuccal and mesiobuccal undercuts.
 Does not separate teeth like a arrowhead clasp.
 0.7mm posteriors 0.6mm anteriors.

23. Advantages
 Small neat and unobtrusive.
 Any tooth.
 Both deciduous and permanent dentition.
 Even on semi erupted tooth.
 No specialized pliers required.
 Can be modified as needed.
 No. of variations are available.

24. Disadvantages
 Unwanted palatal tipping if gets activated.
 May lead to elongation of tooth if is fitting tightly.
 Can be repaired only if fractured through the
arrowheads.
 Cannot be given on proclined anteriors.

25. Modifications Adams clasp with
single arrowhead
 Adams clasp with J hook
 Adams clasp with additional arrowhead
 Adams clasp with distal extension
 Double clasp on maxillary central incisors
 Anterior Adams
 Adams with single arrowhead
 Adams with soldered buccal tube

26. Duyzings Clasp
 Simple design
 engages buccal undercut of molars
 half clasp can also be constructed

27. Active component ofremovable
orthodontic appliances
 Theyare components of the appliances that exertforces to
 bring about the necessarytooth movements .
 The active component includes :
(a)bows
(b)springs
(c)screws
(d)elastics

28. Bows
 Bows are active components that are mostly
used forincisor retraction .

29. Typesof the bows:
(a) Short labial bows :
 Theyare constructed using 0.7mm hard round stainless
steel wire . It consist of bow that make contact with the
most prominent labial teeth and two Uloops that ends as
retentive arms distal to the canine . Theshort labial bow is
activated by compressing the Uloop.
 Indication: Minor overjet reduction and anterior space
closure.

30. Long labial bow
This labial bow is similar to the short labial bow
except that it extends from one first premolar to
opposite first premolar .
The distal arms of the Uloops are adapted over
the occlusal embrasure between the two premolars
to get embedded in the acrylic plate .

31. Indications :
 Minor anterior space closure
 Minor overjet reduction
 Closure of space distal to canine
 Guidance of canine during canine retraction using
palatal retractor
 As a retaining device at the end of fixed
orthodontic treatment

32. Split labialbow
•Thisis alabial bow that is split in the middle .
•Thisresult in two seprate buccal arms having aUloop each .
•Thistype of labial bow show the increase flexiblity ascompared to
the conventionalshort labial bows.
•This type of labial bow is used for anterior retraction .
•Thesplit bow is activated by compressing the Uloop 1-2mm ata
time .

33. Reverselabialbow
 Thisis also called reverse loop labial bows
 Here the Uloop is placed distal to the canine and the free
end of the Uloop are adapted occlusally between the first
premolar and canine .
 Indication are similar to that of short labial bow .
 Activation is done in two step .
 First the U-loop is opened resulting in lowering of the labial
bow in incisor region .
 The compensatory bend is then made at the base of U loop to
maintain proper level of the bow .

35. Highlabial bow with apronsprings
 It consistof heavywirebowof 0.9 mm thicknessthat
extends into the buccalvestibule.
 Apronspring madeof 0.4mmwire isattached to high
labial bow .
 Theapronspringcanbedesignedfor retraction of oneor
more teeth .
 Thistype of labial bow ishighly flexible and isthus used
in casesof largeoverjet .
 Theapronspring isthe activecomponent that isactivated
bybending it towards the teeth , activation of upto 3mm
canbedone.

37. Robert’s retractor
This is alabial bow made of thin guage stainless
steel wire having a coil of 3mm internal diameter
mesial to the canine .
 Asvery thin wire is used for its fabrication ,the
bow is highly flexible and lacks adequate stability in
the vertical plane .
Thusthe distal part of the retractor is supported in
astainless steel tubing of 0.5 mm internal diameter
.

38.  Indications:-
 Patient having severe anterior proclination with over jet
ofover 4mm .

39. Mills retractor
 This is a labial bow having extensive looping
of the wire so as to increase the flexibility and
range of action .
 Mills retractor are indicated in patient with
alarge overjet .
 Disadvantage :-
 Difficult in construction
 Poor patient acceptance

40. Springs
 Springs are the active component of removable
orthodontic appliance that are used toeffect various
tooth movements .

41.  Classification of springs–
(1) Basedon the presenceor absenceof helix theycanbe classified as
simple –without helix
compound –with helix
(2) Basedon the presence of loop or helix they canbe classified as
 helical springs – haveahelix
looped springs – havealoop
(3) Basedon the nature of stability of the springs they canbe classified as:
 self –supported spring
 supported springs

42. Ideal requisites of aspring:-
 It should be easily adjustable.
 The spring should be simple to fabricate
 It should fit into the avilable space with out discomfort to the
patient .
 It should be easyto clean.
 It should apply force of required magnitude and direction .
 It should not slip or dislodge when placed over asloping
tooth surface .
 It should be roust.
 It should remain active over along period of time .

43. Factor to be considered in
designing a spring .
 Diameter of wire :- flexibility of the spring to
a large extent depends upon diameter of wire
F= D4/l3
 F= force applied by spring
 D=diameter of wire
 L= length of wire

44. b)Length of wire :- force can be decreased by increasing the
length of wire . Thus springs that are longer are more
flexible and remains active for long duration of time . By
doubling the length of wire force can be reduced by eight
times.
c)Patient comfort :- spring should be comfortable to patient
in design , shape , size orforce generation . The patient
should be able to insert the appliance with spring in
proper position.
d)Direction of tooth movement :- the direction of tooth
movement is determined by the point of contact between
the spring and the tooth . Palatally placed spring are used for
labial and mesio – distal tooth movement .buccally placed
spring are used when the tooth is to be moved palatally and
in a mesio-distal direction .

45. Fingerspring
 Fingerspringisalsocalledsinglecantileverspringasoneend isfixed in
acrylicandthe otherend isfree .
 It isconstructed using0.6mm wire .
 It consistof activearmof 12-15mmlength ,ahelixof 3mm internal
diameterandretentivearmof 4-5mmlength.
 It isusedfor mesiodistal tooth movementwhen teeth arelocated
correctly in buccolingual direction
 it isactivated bymovingactivearm toward the teeth intended tobe
moved.

47. Cranked single cantilever spring
 It is constructed with 0.5mm wire .
 The spring consist of coil , close to its emergence
from base plate .
 The spring is crankedto keep it clear of the other
teeth .
 It is used to move teeth labially .

49. Zspring
 The‘z’ spring isalsocalleddoublecantileverspring . It
ismadeupof 0.5mm wire .
 Thespringconsistof two coil of verysmall internal
diameter .it should beplaced perpendicularto palatal
surfaceof tooth .
 Thespringcanbemadefor movementof singleincisor
or two incisor.
 It isactivated byopening helicesbyabout 2-3 mmata
time .

51. Tspring
 It is made of 0.5 mm wire .
 The spring consist of t shaped arm whose arm are
embedded in acrylic.
 It is used for buccal movement of premolar and
some canine .
 It is activated by pulling the free end of the t toward
the intended direction of tooth movement.

53. Coffin spring
 It ismadeof 1.2mmwire .
 It consistof au or omegashapedwire placed in the
midpalatal region with retentive arm incorporated in
baseplates .
 It isretended byadamsclaspin molar .
 It isused in slow dentoalveolararchexpansionin
patient withupperarchconstriction or in unilateral
crossbite

55. Canineretractors
a) Basedontheir location
 buccalcanine retractor
 canineretractor
a) Basedonthe presenceof helixor loop
 canine retractor with helix
 canine retractor with loop
c) Basedontheir modeof action
 Push type
 pull type

56. U loop canine retractor
 It is made up of 0.6 or 0.7 mm wire .
 It consist of u loop , an active arm and a retentive
arm that is distal .
 It is used when minimum retraction of 1-2mm is
required .
 It is activated by closing loop by 1-2mm or cutting
the free end of active arm by 2mm and readapting

58. Helical canine retractor
 It is also called reverse loop canine retractor and is
made of 0.6 mm wire .
 It consist of acoil of 3mm diameter , an active arm
and a retentive arm .
 It is activated by opening helix by 1mm or by cutting
1mm of free end and readapting it around the canine

59. Buccalcanineretractor
 Itis indicated in bucally placed canine and canines
placed high in the vestibule .
 They are used to move canine in distal aswell as
palatal direction .
 It consist of acoil of 3mm diameter , an active arm
and a retentive arm .

60.  Buccal canine retractor are of two types
 Supported
 self supported

61.  Self supported are made of thicker gauge
wire(0.7mm) so that the spring can support itself
and supported are made of thinnergauge wire
(0.5mm) thus they are more flexible and
mechanicallyefficient

62. Palatal canine retractor
 It is made up of 0.6mm wire .
 It consist of coil of 3mm diameter , an active arm a
guide arm .
 It is indicated in canine that are palatally placed.

63. Screws
 Screw are active component that can be
incorporated in a removable appliance . Screw
can be activated by the patient at regular
intervals using akey.
 Removable appliances having a screw usually
consist of split acrylic plate and adams clasps on
the posterior teeth. The screw is placed connecting
the split acrylic plate.

64. Screw can bring about three
types of movement
Expansion of arch
Movement of one or a group of teeth in a buccal or
labial direction .
 Movement of one or more teeth in a distal or
mesial direction

65. Elastics
 Elastics as active components are seldom
used along with removable appliances . They are
mostly used in conjunction with fixed appliances

66. Baseplate
 The bulk of removable appliance is made of the
acrylic base plate .
 The prime function of the base plate is to incorporate
all the components together into the single function
unit .