Removable Orthodontic Appliances Undergraduate class for 3rd year BDS

1. REMOVABLE APPLIANCES
Dr. SHAIKH ANALHAQ A.

2. Definition
REMOVABLE APPLIANCE ARE ORTHODONTIC
DEVICES WHICH CAN BE TAKEN OUT BY THE
PATIENT FOR CLEANING AND WHICH ARE
DESIGNED TO APPLY FORCES TO THE TEETH BY
MEANS OF SPRINGS SCREWS AND OTHER
MECHANICAL COMPONENTS.

3. 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 appliance-
prolongs 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
Advantages Disadvantages

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

5. Components of removable appliances
Retentive Components
Baseplate
Active components

6. Retentive Components
Retention: Means whereby displacement of appliance
is resisted.
Clasp: any hook or band attached to a natural tooth
and used to anchor a partial denture or an
orthodontic appliance.

7. CLASPS
The name clasp is derived from a French
word “UYPTAN” which means “to embrace”.
Clasps are the retentive components of the
orthodontic appliances.

8. 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.

9. USES
• To secure the appliance in position
• To prevent rolling of appliances
• To resist forces of displacement
• To provide retention & anchorage
• For engaging elastics

10. 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.

11. 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

12. 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

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

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

15. • Adams clasp / modified arrowhead clasp /
liverpool clasp / universal 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.

16. 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.

17. 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.

18. Modifications
Adams clasp with single arrowhead:
Adams clasp with J hook
Adams clasp with additional arrowhead

19. Adams clasp with distal extension
Double clasp on maxillary central
incisors

20. Schwarz Clasp
Designed by C. M. Schwarz
Oldest & for a considerable amount of time most
generally used
Adj: Arrowhead bent towards papilla to engage
undercuts
 Can be used in deciduous or permanent teeth
 Skill to fabricate
 Can be used only on posterior teeth

21. Duyzings Clasp
-Simple design
-engages buccal undercut of molars
-half clasp can also be constructed
Adj: Bending towards the tooth or undercut area

22. Southend Clasp
-0.7 mm wire
-spans two adjacent margins of anterior teeth
Adj: readapting into interdental area
 Esthetically more pleasing

23. Ballend Clasp
• Wire having a knob or ball like structure on one end
• utilizes interdental undercuts
• Indicated when additional retention required

24. 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
Adj: -hold retentive loop and twist inwards
-bending towards interdental undercut as it
emerges from acrylic

26. 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.

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

28. Active components
 Labialbow
 Springs
 Elastics
 Screws

29. LABIAL BOWS
• Labial bow is an essential component of
removable orthodontic appliances
• It can be either active or passive

30. • The principal function of the bow is to retrude
the anterior teeth
• It can be used for retentive purposes

31. Parts of labial bow
• The incisor segment
• Vertical loops
• The occlusal or cross
over section
• The retentive ends

32. Types
• Short labial bow
• Long labial bow
• Roberts retractor
• Reverse labial bow
• Begg’s labial bow
• Mills retractor
• Fitted labial bow
• High labial bow with apron springs
• Split labial bow

33. Short labial bow
Indications
• Retraction of anteriors
• Anterior spacing with proclination
• Overjet reduction
There should be good contact between canine
and premolar

34. • 0.7mm wire used
• Fabrication:- labial segment of wire is placed
at the junction of the incisal and middle third.

35. Vertical segment starts from mesial third of canine,
should be perpendicular to the incisor segment &
should be away from gingiva
Occlusally, it passes between canine and premolar

36. Retentive ends adapted on the lingual or palatal side.
Activation - Compressing the U-loop by 1mm

37. Long labial bow
Indications
• Anterior space closure
• Overjet reduction
• Closure of the space distal to the canine
• As a retaining device at the end of fixed
therapy
• Guidance of canine during canine retraction
using palatal retractor

38. • 0.7 mm wire used in active purpose
• 0.9 mm wire used in passive purpose
• Fabrication - same as short labial bow but
occlusal wire passes between two premolars
• Activated by compressing the U-loop

39. Roberts retractor
• It was first designed by G.H Robert
• Indication
it is suitable only for retraction of four incisors
following retraction of canines

40. • This is a flexible bow which is constructed from
0.5 or 0.6 mm wire inserted into a stainless
steel tubing to give support to either end of the
bow

41. • Fabrication
Labial segment of wire is placed at the junction of the
incisal and middle third
Extends only two thirds of the mesiodistal width of the
lateral incisors
A coil of 3mm internal diameter placed mesial to
canine
Distal part is supported in a stainless steel tubing

42. • It is activated by closing the coil or giving palatal bend
at the emergence of the coil

43. Reverse labial bow
• Indication
For retaining tooth positions
For minor tooth movements

44. • 0.7 mm wire used
• Fabrication:-loops are placed distal to the
canine and the free ends of the U-loops
are adapted occlusally between the
premolar and canine

45. • This is too stiff for effective incisor retraction
• The stability ratio is poor
Activation
First the U-loop is opened this results in lowering of
the labial bow in the incisor region .
A compensatory bend is given at the base of the
loop

46. Begg’s labial bow
(Wrap Around / Around the Globe Bow)
• Popularized by P.R . Begg
• It is used as retainer after fixed orthodontic
therapy
• 0.9 mm wire is used

47. • Fabrication
consists of labial wire that extends till the last erupted
molar
U-loop is incorporated at the pre molar and molar area
to close the band spaces

48. • Advantage of this bow is that there is no cross-
over wire between the canine and premolar
there by eliminating the risk of space opening
up

49. Mills retractor
• It is also called extended labial bow
• Indication
Large overjet
For alignment of irregular incisors

50. • 0.7 mm wire is used
• This labial bow has an extensive looping of the wire so
as to increase the flexibility and range of action
• Poor patient acceptance
• Complex design

51. Fitted labial bow
• Used to secure the incisors firmly after they been
rotated
• It acts as retainer
• It is not used in active tooth movement
• 0.7 mm wire is used

52. High labial bow with apron spring
• Used in retraction of one or more teeth
• Large overjet
• It is very similar to a Roberts retractor
• Highly flexible
• Light force

53. • Fabrication
A heavy base arch of 0.9mm to 1mm wire extends into
the buccal sulcus
apron spring made of 0.4mm wire is attached to the
high labial bow

54. • Activation
It is activated by bending the upright arms of the apron
springs towards the teeth
3mm activation at a time
Disadvantages are difficulty in construction and soft
tissue injury

55. Split labial bow
• Used for anterior
retraction
• Closer of midline
diastema

56. SPRINGS
Most commonly used active elements
Requirements:
 springs should deliver optimum force
 should possess high degree of elasticity
 should have long range of action

57. Force systems delivered depend on
Intrinsic properties- cannot be altered by operator
-modulus of elasticity
-yield strength
Extrinsic properties- operator can exercise control
-length of wire
-thickness of wire
Small changes in diameter and length have a profound
impact on the force delivered

58. Effect of wire diameter on force delivered
-amount of activation
0.5mm- 3mm activation
0.7mm- 1mm activation- little margin of error
Effect of wire length
Coil- increase length of spring
Lower force with same amount of activation

59. Classification of Springs
I. Based on direction of tooth movement
1. Springs for mesio-distal tooth movement
2. Spring for labio-lingual tooth movement
3. Springs for expansion of arches
II. Based on nature of support
1. Self supported springs
2. Guided springs
3. Auxiliary springs
III. Based on presence of loop or helix

60. Single Cantilever Spring
active arm
Parts coil
retentive arm
• 0.5-0.6mm wire
• coil with internal diameter of 3mm
• used to move teeth labio-lingually or mesio-diatally

61. Double Cantilever Spring / Z spring
• Constructed using 0.5 or 0.6 mm wire
• Spring perpendicular to palatal surface of tooth
• Indicated where incisors are to be proclined
Activation: Opening both coils
 If not perpendicular to palatial surface of teeth, it
tends to intrude teeth.

62. ‘T’ Spring
• Constructed using 0.5 mm wire
• Buccal movement of premolars and molars
Activation: Pulling spring away from the baseplate

63. Coffin Spring
• Described by Walter.H.Coffin in 1881
• Made in 2 segments, large enough to make contact
with all teeth to be moved
• Made of 1.25 mm wire
• Spring stands 1 mm away from the soft tissues

64. Indications:
Transverse arch expansion – Unilateral crossbite with
lateral mandibular displacement
Advantage over screw – Differential expansion can be
obtained.
 Unless expertly made and adjusted, tends to be rater
unstable.

65. Canine Retractors
• Type of spring
• used to move canine in distal direction
CLASSIFICATION
I. Based on location -buccal
-palatal
II. Based on presence of helix or loop
III. Based on mode of action -push type
-pull type

66. Buccal Self Sopported Canine Retractor
• 0.7 mm wire
• buccally placed canine is to be moved palatally and
distally
• coil just distal to long axis of tooth

67. Activation: by 1mm
Distal -closing the loop
Palatal -anterior limb is bent towards the tooth
after it emerges from the coil
 Uncomfortable to patient
 Stability increased- flexibility compromised

68. Supported Buccal Canine Retractor
• identical in design to self supported retractor
• 0.5mm wire supported in tubing
Activation: by 2mm

69. Reverse Loop Canine Retractor
• can be used in shallow sulcus
Activation: 1mm
i. cut off 1mm from the free end & readapt it
ii. opening the coil

70. ‘U’ Loop Buccal Canine Retractor
• can be used in sallow sulcus
Activation: free end is cut by 1mm & readapted
 Requires frequent adjustment

71. Palatal Canine Retractor
-canine placed palatally requiring distal buccal
movement
-coil of 3mm placed between the initial & final position
of canine

72. THANK
YOU