2. DEFINITION
ORTHODONTIC APPLIANCE
Orthodontic appliances are appliances by means of
which pressure can be applied to a tooth or group of
teeth in a predetermined direction.
3. DEFINITION
REMOVABLE APPLIANCE
A removable appliance is a base plate usually acrylic
resin to which attached various claps, spring etc and the
appliance can be inserted and removed by the patient.
(BSI,1969)
4. INDICATIONS
Indications for the use of removable appliances:
When tipping movement is required
For rotational movement of teeth which are broad
mesio-distally
For overbite reduction with the use of anterior bite
plane
For space maintenance
For retention at the end of active treatment
5. ADVANTAGES
The advantages of removable appliances:
Can be removed for tooth brushing, socially sensitive
occasion or if any damage or problem
Palatal coverage increases anchorage
Easy to adjust
Arcylic can be thickened to form either anterior or
posterior bite plane (bite plane can be incorporated)
6. Useful as a passive retainer or space maintainer
Can be used to transmit forces to blocks of teeth
Control is less complex because only simple tooth
movements are affected
Less expensive
7. DISADVANTAGES
Disadvantages of removable appliances:
Appliance can be removed by non-complying patients
Only simple malocclusion can be corrected (Only
tipping movement possible)
Inefficient for multiple individual tooth movements
Lower removable appliance are difficult to tolerate
Affects speech
8. DESIGNING REMOVABLE APPLIANCES
Four components need to be considered for every
removable appliances:
Active component
Retaining the appliance
Anchorage
Baseplate
(ARAB)
9. ACTIVE COMPONENTS
The component which exert the force which moves the
teeth
Includes:
Springs (commonly used)
◼ Z-spring and double cantilever
◼ Finger spring
◼ T-spring
◼ Buccal canine retractor
◼ Coffin spring
Screws
Labial bow (can be active or passive component)
10. Z-spring & double cantilever
These springs are used for rotational movement
and/or labial movement of teeth.
Constructed from 0.5mm stainless steel wire (SS)
2 coils (2-3mm in diameter)
Seated 90° to palatal surface of the incisor
Activation : open the coil by 2-3mm
11.
12.
13. Finger spring
To move tooth along dental arch, distal or mesial.
Constructed from 0.5mm stainless steel wire (SS)
Coil- 3mm diameter, midway between gingival
margin and the midline of palate.
Activation: hold the coil with plier and push with
finger the free-end half a tooth width.
14.
15.
16. Guard wire
Function is to support springs
0.5mmSS
Longer on the side where the tooth is moved
17. T-spring
For buccal movement of a single premolar or molar
tooth
Constructed from 0.6mm stainless steel wire (SS)
Spring position at the palatal side of the teeth to
be moved.
Activation: the vertical arm of the T-spring should be
bend to displace the horizontal arm towards the
tooth.
18.
19. Buccal canine retractor
To retract or distalized the canine when canine is
placed labially or high in sulcus
When requires the movement of canine both distally
and palatally.
Can be given only in the upper arch.
Made up of 0.7mm SS or 0.5mm SS (requires tube
sleeve to prevent distortion.)
20. Activation:
To bring about distal movement, the free end is cut
short by 1mm and is readapted to engage the mesial
side of the canine
To bring about palatal movement, the active arm is
bent at a point where it emerges out from the coil.
21.
22. Coffin spring
To expand upper arch transversely
Constructed from 1.25mm SS
Activation: the central curved portion is flattened
using finger pressure or plier so that the two halves
of the appliance move apart
23.
24. Expansion screws
To move more than one tooth
To expand arch transversely/ anterior-posteriorly
Activation: patient turning the screw by the screw’s
key
25.
26.
27. Labial bow
Functions are to retract upper labial segment and
also for retention
To reduce OJ<4mm
Constructed from 0.7mm stainless steel wire (SS)
Split labial bow used to increase flexibility for
reducing OJ
Activation: closing U-loop
28.
29. Retentive Component
Means by which the appliance is retained in the
mouth
Orthodontic removable appliance should have 3
points retention to be sufficiently retentive
Retentive component include:
Adam’s clasp
Southend clasp
Ball-hook clasp
30. Adam’s clasp
Constructed from 0.7mm stainless steel wire (SS) for
molars and incisors and 0.6mm SS for premolars
and canines
Adjustment with Adam’s plier
31. Southend Clasp
Constructed from 0.7mm stainless steel wire (SS)
For anterior teeth
Adjustment with Adam’s plier
32. Ball end clasp
It is use for retention purpose
Normally used for anterior teeth
Preformed ball end claps are available
Adjustment with Adam’s plier
33. Anchorage
The manner in which the applied force is resisted.
When the active components of RA are activated,
the reaction for the appliance to move in the
opposite direction
The ability to resist this adverse movement is call
anchorage.
34. Provided mainly by:
the base plate moving against the palatal vault or the
anterior portion of the mandible.
the teeth, the more teeth the base plate embraces the
greater the anchorage
the retention of the clasp
35. Base plate
Means whereby the various components of a
removable appliance are attached to.
Normally made up of arcylic resin, should be thin
and smooth but thicker in the lower to increase
strength.
Can be modified to include:
Anterior bite plane (ABP)
Posterior bite plane (PBP)
36. Anterior bite plane
Raised platform in the anterior part of the URA
Function:
To reduce OB
To relieve posterior occlusion when correcting buccal
CB/ Scissors bite
37.
38.
39.
40. Posterior bite plane
Raised base plate over the occlusal surfaces of
posterior teeth
To allow correction of anterior crossbite
