Removable appliances

Removable Orthodontic Appliance

Types:
it can be divided into two Main Types:
Removable appliance for growth modification (Functional Appliance)
Removable appliance for tooth movements.
Removable Orthodontic Appliance for Tooth Movements
Definition:
An appliance that is not fixed to teeth but can be removed by the
patient.
Indications:
Skeletal pattern should not be far from Cl.I the increase or decrease in overjet mainly due to change in incisor inclination.
It should be possible each arch individually.
Planned extraction should allow tipping movement to correct the malposition.
Any malposition teeth should have their apices fairly well in line.
Fault of buccolingual occlusion should be associated with a mandibular displacement. As unilateral cross bite of the posterior teeth.
Extraction should provide slight excess space or just sufficient space.
Contraindications:
Also six points: which are exactly the opposites of indication points.


Components
Acrylic Base Plate
Retentive Components
Active Components
Acrylic Base Plate
Construction:
Either from hot or cold cure acrylic resin.
Extension:
It extend to be closely fit around the neck of teeth as large no. as possible except when the clasps are placed over permanent first molar, it's better not to extend distally to area of second molars to be well tolerated.
Thickness: it make as wax sheet thickness 2-3 mm.
Colour:
Different colours are provided by the manufactures to be acceptable by the
patient especially the children.
Functions:
Foundation into which retentive and active components are embedded.
Anchorage: it contribute in the preservation of anchorage (act as media for transporting anchorage forces) through two ways:
Close fit of the acrylic around the neck of the teeth especially those which carry the clasps.
Contact of the appliance with mucosa of the vault of palate especially those part which has vertical inclination.
As active component: the base plate may be thickened or extended locally to form bite planes which will have an active effect on tooth position, which are:
Anterior Bite Plane:
It considered as thickened platform of acrylic, palatal to the upper incisors, on which lower incisors can occlude leaving the posterior teeth out of occlusion for 1-2 mm for all teeth and (for right and left side) and the lower incisors touch the base plate uniformly at the same time.
Clinical Applications:
it's used temporary relief of cuspal lock for the correction of:
Bucco-lingual abnormalities in the buccal segment
Increased incisal over bite in a typical Cl. II malocclusion.
Clinical Limitations:
Sever Cl.II malocclusion with skeletal discrepancy.
Increased lower facial height.
Adjustment:
Monthly appointment to observe the over eruption of the posterior teeth that may need further application cold cure acrylic resin to separate posterior teeth for more bite opening.
Posterior Bite Plane:
A base plate which covers the occlusal surfaces of the posterior teeth bilaterally to prop the bite to relieve cuspal lock where it must be of uniform thickness that giving even occlusal contact and minimum separation.
Clinical applications:
Incisor cross bite.
Buccolingual correction
Retentive Components
Definition:
Those component by their action the appliance stay in the mouth.
Necessity of Retention:
Mechanical efficiency of active component.
Good patient adaptation, habit discouraged and initial difficulty with
speech and eating are minimized.
No risk for extra oral application.
High anchorage value.
Types of Retentive Components:
Adams' Clasp: (Two arrowhead connect by bridge)
Clinical Applications:
 a. Single Clasp of 0.7 mm used on 6 or 3
 b. Double clasp of 0.7 mm used on 4&5 or1&1
 c. Single clasp of 0.6 mm used on C
 d. Double clasp of 0.6 mm used on D&E
Clinical Limitation:
a. Proclined upper incisors.
b. The need for clasping mesiobuccal corner 5 but can be solved by
soldering on bridge of Adams.
Advantages of Bridge in Adams' Clasp:
These are providing site for:
a. Finger tip to apply pressure during appliance removal.
b. Auxiliary spring soldering.
c. Hook soldering for inter or intramaxillary elastic traction
d. Tubes to receive a face extra oral traction.
Single Arrowhead Clasp (0.8 mm with out bridge):
Clinical Applications:
a. Mesiobuccal corner of 5 .
b. Lower appliance which already of poor retention.
Advantages:
Accurate positioning and adjustment is easy (absence of bridge)
Good adaptation.
Incisors Clasps:
Short Fitted Wire:
 (0.7 mm used on 1&1 without arrowheads and sometime bilateral loops may add for further adjustment)
Clinical Application & Advantages:
Proclined incisors.
Midline diastema.
No mesial pressure on centrals from arrowheads.
Long Fitted Wire:
(as short fitted wire lies on midway of labial surfaces but it involves 1,1,2&2 )
 It offers the followings:
Good retention that engage some undercuts among incisors
High flexibility and good strength.
Less prone to damage by lower incisors as it cross between 2&3
Long Labial Bow:
it aids in retraction of incisors following canine retraction where its flexible due to incorporation of bilateral U- shape loops, in addition it provide static anchorage against protraction of retruded incisors
Miscellaneous Clasps:
I) Circumferential Clasp or C-clasp :
C-shape clasp especially used for second molar & occasionally for canine, although its main advantage less occlusal interference than Adams clasp, it offer poor retentive ability than the later.
II) Ball Clasp:
It has ball shape end , fabrication is easy but because of their short span it relatively stiff & unable to extend deeply into the undercut as an Adams clasp.
III) Lingual Extension Clasp:
Short loop of 0.4 mm wire plased into first molar-second premolar embrasure from the lingual, it provide enough retention for retainer rather than active appliance.


ACTIVE COMPONENTS
Those components which exert the force that produce tooth movements.
Types:
Springs
Elastics
Screws
SPRINGS
Mechanical Principles:
The force should be delivered at right angles to the long axis of the tooth.
Failure: vertical component of force tend to displace springs.
As far as possible the force should be applied through a surface which is
parallel to the long axis of the tooth.
Failure: tend to displace springs & intrude the tooth.
The force should pass through the center of resistance of the tooth
(approximately the center of tooth viewed in cross section).
Failure: tendency for the tooth to rotate.
Classification of Springs:
Spring for Mesiodistal movement.
Spring for Buccal movement.
Spring for Lingual movement.
Spring for Overjet reduction & alignment of incisors.
Spring for arch expansion.
Spring for Extrusion movement.
Spring for Mesiodistal Movement
Palatal Finger Spring
(0.5 or 0.6 mm diameter, 2 cm in length till insertion in
acrylic with coil of 3-4 mm and either boxed or open)
Buccal Canine Retractor: (0.7 or 0.5 mm with coil of 3 mm diameter)
An alternative Buccal Retraction Spring:
it same the previous & it s useful when the sulcus is shallow but its
rigid & difficult control of activation
Spring for Buccal Movement
Cranked Palatal Spring: (0.5 mm, a crank is bent into the spring to avoid
contact with adjacent teeth in later stage of activation).
Z-spring & double Z-spring: ( 0.5 mm, mainly for one or more palatally displaced incisors)
T-spring: (0.5 mm, mainly to produce buccal movement of buccal teeth).

Spring for lingual movement
(0.7mm wire diameter)
Molar Spring
Canine (modified canine retractor) & Premolar spring
Single Incisor Spring
Soldered Auxiliary Spring: (0.6 or 0.7 mm wire)
Spring for overjet reduction & alignment of incisors
Heavy Wire:
Labial Bow with Small Loops (0.7mm): it produce excessive pressure.
Labial Bow with Large Loops (0.7mm) it produce suitable pressure but its activation is difficult & can traumatize the sulcus.
Light Wire:
Roberts retractor:
its (0.5 mm) &offer light force but can traumatize the sulcus &
breakage need reconstruction of appliance.
The apron spring.
Self straightening spring.


Spring for Arch Expansion
Coffin spring:
1.25 mm wire used in case where lateral expansion is need. It require four retentive clasps & place as high as possible for patient acceptance.

Spring for Extrusion movement

Modified Finger Spring:
It acts in combination with edgewise bracket bonded on labial surface of the teeth specially incisors.

Elastic Traction

Intramaxillary Traction (within single arch)
Intermaxillary Traction (between upper & lower arch)

Screw

Position
In molar region regarding curve of spee
In molar region parallel to buccal segment
For expansion, it will be positioned in the midline where place horizontally
but if unilateral crossbite, it will be positioned parallel to palatal mucosa
Clinical Indications
Expansion
Distal movement
Cl.III cases
ADJUSTMENT
It need for active, retentive component & acrylic base as following:


Active component Activation
Spring for (mesiodistal movement):
1/3 for 0.7 mm or 1/2 for 0.5mm (30-50 gm force) if greater, pain, anchorage loss, displacing the appliance & unwanted tooth movement.
Labial wire: closed loop 1mm.
Spring for (buccal movement): flex it upward & forward.
Screws: weekly open half turn (0.2 mm)
Elastics: daily replaced by new one.

Retentive component

Adams Clasp: ensure good fitness by further activation, if too much,
clasped tooth position will change & loss of anchorage.
other types: also ensure their fitness.

Acrylic Base Plate

Adjust Anterior or Posterior Bite plane by removing or placing acrylic as
need.
Removing acrylic in direction of tooth movement.
Slight relief at areas of tissue injury.

Instructions for Using

Insertion: anterior part is first & progress gradually till buccal spring end
with most posterior clasp like Adams clasp.
Removal: exactly opposite to path of insertion.
Home use:
Verbal & printed information should be provided for patient.
Day & night wear of appliance except at cleaning or vigorous sport or at
eating in case of cold cure appliance, where placed in a rigid container.
Cleaning: using tape water & patient own or nail brush.
Excessive salivation & difficult swallowing will subside within few hours.
Normal speech take 24-48 hours to achieve.
Contact with operator in case of pain, soft tissue trauma or breakage.
Supply patient with soft carding wax to apply over loops &other parts to
minimize irritation.


 SHAPE \* MERGEFORMAT 
  SHAPE \* MERGEFORMAT 
  SHAPE \* MERGEFORMAT 



  SHAPE \* MERGEFORMAT 
  SHAPE \* MERGEFORMAT 
  SHAPE \* MERGEFORMAT 



 SHAPE \* MERGEFORMAT 
  SHAPE \* MERGEFORMAT 
  SHAPE \* MERGEFORMAT 



  SHAPE \* MERGEFORMAT 
  SHAPE \* MERGEFORMAT 
 ] SHAPE \* MERGEFORMAT 



 SHAPE \* MERGEFORMAT 
  SHAPE \* MERGEFORMAT 
  SHAPE \* MERGEFORMAT 


 SHAPE \* MERGEFORMAT 
  SHAPE \* MERGEFORMAT 
  SHAPE \* MERGEFORMAT 




 SHAPE \* MERGEFORMAT 
  SHAPE \* MERGEFORMAT 
  SHAPE \* MERGEFORMAT 




 SHAPE \* MERGEFORMAT 
  SHAPE \* MERGEFORMAT 











 PAGE \* MERGEFORMAT 4

Anterior Bite Plane

Posterior Bite Plane

Adams Clasp

Single Arrowheads

Adams Clasp
On Canine

Adams Clasp

On Centrals

Cranked Palatal Spring

Finger-spring

Z-spring

Canine Retractor

Alternative Buccal Retraction Spring

Incorrect position

Premolar Spring

Molar Spring


T-spring

Canine Spring

Premolar Spring

Incisor Spring

Long Fitted Incisor Clasp

Labial Arch

Robert Retractor

Coffin Spring

Screw