There are two types of removable appliances - active appliances used for tooth movement and passive retainers or space maintainers. Removable appliances only produce tipping movements of teeth and cannot achieve other movements like bodily, intrusion, or rotation. Components include an active part to move teeth, retentive parts like Adams clasps using undercuts, and an acrylic base. Common facebows attached to the upper jaw include short and long labial bows, split labial bows, and Robert retractors. Removable expanders can expand the dental arch up to 1.5-2 mm per side while fixed expanders can achieve up to 11 mm of expansion.

1. removable appliances
2 types of removable appliances.
Active: functional appliance for growth modification (tooth movement is
produced)
Passive: retainer, space maintainer
Removable appliances just produce a tipping movement .
Disadvantage: only one type of movement, (bodily, intrusion, extrusion, rotation
are not achieved by removable appliances)
Components of removable appliance:
 Active part
 Retentive part
 Acrylic base
The retentive part such as a clasp ( Adams most commonly) Could be used with
fully or partially erupted, deciduous, or permanent, anterior or posterior,
hygienic, and it doesn’t interfere with the apposing tooth.
Clasps take their action from 2 aspects:
 Buccal and lingual undercuts
 Mesial and distal undercuts
Adams clasp utilizes mesiobuccal and distobuccal undercuts.
Lingual clasp is mainly between the 2nd premolar and the 1st molar embrasure.
Universal adams has 2 arrow heads.
With deciduous or partially erupted a single arrow head clasp is used.
Face bows are mainly attached to the upper jaw.
 6 types of the bows :
 Short labial
 Long labial
 Split-labial
 Reverse labial
 Robert retractor
 Mid-retractor

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Split labial : is formed from 2 separate parts (not continous)- used
to treat minor overjet or to close the diastema .
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Robert retractor : same as short labial but the only difference is
that it has a COIL at the bottom of the u-shaped loop to increase the
flexibility .
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Short labial : most common use –could be passive ( part of the
retentive appliance ) or active (move the teeth ) – activation done
through closing the loop around 1-2 mm .
Mid-retractor : multiple binds to reduce the force .
Light and continuous force is the best one for orthodontic treatment!
Clasp & retainers done with the size equal or more than 0.7 diameter !
T-spring pushes the teeth toward the buccal side
Requirement of springs :
 Simply fabricated
 Fixed in its proper position
 Easy to clean
 Apply the required force
 Remain active over a long period of time
 Should not slip
 Easily acceptable
 Factors affecting spring action :
 Diameter : large diameter=less flexibility ‫عكسية‬
 Length: increased length = more flexibility ‫طردية‬
 Force .
 Types of expansion :
 Skeletal : with fixed scrows ( rapid palatal expansion )
 Dental : with removable expanders.
 -The removable expander : for expansion maximum 1.5 – 2 mm per side
(increase transverse measurements)
 -fixed expander : we can reach up to 11 mm .
 - 0.25mm with each screw opening , E.g. 4 turns will give us 1 mm .
 - with removable appliances , we get 1 mm per month with one turn per
week .
 -the maximum is 2 turns per week .

3.  -rate of activation of rapid palatal expander is 2 turns per day ( we reach
within 21 days 11mm)
 - rapid palatal expander is painful due to opening in the palatal sutures .
 - we need to protract the maxilla (protractor) if we have a small maxilla in
case of class 3 , but if we have a huge mandible then chin cap .
 -in case of class 3 with a combination of both : we cant simply combine
protractor with a chin cap .
 -elastics are most commonly used with fixed appliances , but still can be
used with the extension of the adam’s clasp or the short labial .
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