38 Removable appliances

38

Removable appliances

Table 38.1Commonly used active components of removable appliances and their uses

Active components Fabrication (ss, stainless steel wire) Use
Labial movement
Double cantilever spring (Z-spring)
0.5–0.6 mm diameter ss Proclination of 1 or 2 incisors (good range) (Activate by pulling away from baseplate at 45°)
T-spring 0.5–0.6 mm diameter ss Proclination of an incisor/premolar/molar (poor range) (Activate by pulling away from baseplate at 45°)
Recurved spring 0.8 mm diameter ss Proclination of all four incisors
Cross-over wires 0.7–03 mm diameter ss Proclination of all four incisors
Screws Proclination of multiple incisors where retention poor
Palatal movement
Roberts’ retractor
0.5 mm diameter ss (sleeved) Retraction of prolined and spaced maxillary incisors
Buccal canine retractor 0.5 mm (sleeved) or 0.7 mm diameter ss (unsleeved) Palatal and distal movement of mesially angulated canines
Elastics Different diameters available Force dependent on the root surface area of teeth to be moved
Distal movement
Palatal finger spring
0.5–0.7 mm diameter ss (guarded) Distal movement of canines, premolars and molars
Headgear Distal movement of molars, J-hook headgear for incisor retraction
Expansion
Screw
Correction of buccal crossbites
Coffin spring 1.25 mm diameter ss Buccal crossbite correction
Rotation
Whip spring
0.5 mm diameter ss Correction of mild rotations
Extrusion and Intrusion
Elastics
Different diameters available Force dependent on the root surface area of teeth to be moved

Figure 38.1 (A) Examples of active removable appliance components: (i) Z-spring (arrow) and T-spring, (ii) recurved spring, (iii) cross-over wires, (iv) Roberts retractor, (v) buccal canine retractor, (vi) elastics, (vii) palatal finger spring for distal molar movement and (viii) midline expansion screw. (B) Examples of retentive removable appliance components: (i) Adams clasp, (ii) Southend clasp, (iii) C(ircumferential)-clasp, (iv) ball ended clasps and (v) labial bow.

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Jan 1, 2015 | Posted by in Orthodontics | Comments Off on 38 Removable appliances
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