Sagittal, vertical, and transverse changes consequent to maxillary molar distalization with the pendulum appliance

The purpose of this study was to evaluate the skeletal and dental changes in patients who underwent distalization of their maxillary molars with pendulum appliances.

The sample consisted of 31 patients (initial mean age, 14.58 years) with Angle Class II molar relationships and all permanent teeth up to the second molars. The maxillary molars were distalized with pendulum appliances for a mean period of 5.87 months. Lateral cephalograms, 45 degrees oblique radiographs, and dental casts were obtained before and after distalization. Changes produced by the pendulum appliance were analyzed with paired t tests.

Maxillary first molar distalization accounted for 63.5% of the space opening; mesial movement of the maxillary first premolars contributed 36.5% of the space. The mean space opening on lateral cephalograms was 7.25 mm, and the rate of molar movement was 1.23 mm per month. The mean distalization of the maxillary molars was 4.6 mm, with a mean distal crown tipping of 18.5 degrees The maxillary molars experienced expansion, with a smaller effect on the first molars than on the second molars. The pendulum appliance produced symmetrical expansion, with a rate of 1.04 mm per month on the right and 1.10 mm per month on the left.

The pendulum appliance is effective for distalization of the maxillary molars and the establishment of a Class I molar relationship in a relatively short time. However, caution is needed to control collateral effects, including mesial movement of the first premolars and distal tipping of the molar crowns.