PENDEX APPLIANCE

One of the treatment modalities for correction of dental Class II malocclusion (without  skeletal involvement) consists of distalisation of the maxillary first molars to a Class I  relationship by 4-5mm. This, however, does not comprise of any vertical alteration or involvement of the mandibular arch due to this procedure. Traditionally, Molar Distalisation  was done using extraoral forces, but this had the disadvantage of being strictly dependent on  patient compliance, which usually compromises the final treatment results. Later on, Intraoral  appliances for molar distalisation were found which were less dependent on patient  compliance. Among these appliances are the Magnets, Jones Jig, superelastic coil springs,  Herbst, Distal Jet, Pendulum, and Pendex.

The Pendulum Appliance, initially described by Hilgers, did not provide transversal molar  control while in movement, thus leading to posterior crossbite (because the molars move in  an arc). In order to avoid this, Hilgers added an expansion screw to it, thus the Pendex was  invented.

Advantages:  

• shorter treatment time

• constant load on molars

• does not depend on patient cooperation

Disadvantages:

• molar tipping

• premolar mesialization

• loss of anterior anchorage

Indications:

• Need of transverse correction

• Moving back molar(s) by 4-5mm over 2 or 3 activations to preserve anchorage. • Molar derotation

Components:

• An acrylic palatal button

• An expansion screw

• 4 wires for retention of the appliance arising from the palatal button and banded or  bonded to the maxillary first and second premolars.

• 2 wires with single helices arising from the palatal button which insert into the lingual  sheaths of the maxillary first molars after activation.