A common strategy for
correcting Class II malocclusion without extraction
is to distalize the molars.
The Distal Jet, described by Carano & Testa (1996),
is the most widely used distalizer device in
Orthodontics as it provides good distalization with
minimum side effects compared to others (Chiu et
al., 2005).
The Distal Jet consists of a bilateral piston and
tube arrangement, with the tube embedded in an
acrylic Nance button in the palate, supported by
attachments on the first or second premolars. A
bayonet wire is inserted into the lingual sheath of
each first molar band and the free end is inserted
into the tubes, much like a piston. A nickeltitanium
open-coil spring and an activation collar are placed
around each tube. Compressing the coil spring
generates a distally directed force. The activation
collar is retracted and the mesial setscrew in each
collar is locked onto the tube to maintain the
force. The active components have to be placed
palatally. Ideally, they result in lines of force
running close to the center of resistance of the
molars. As opposed to the cervical headgear with
which molar distalization can be achieved only as a
combination of dental crown tipping with subsequent
root uprighting, the biomechanics of the appliance
should, in theory, allow translatory molar
distalization.
Key words: distal jet, class II malocclusion, molar
distalization.
