Dentoalveolar and skeletal changes associated with the pendulum appliance

The purpose of the study was to examine the dentoalveolar and skeletal effe cts of the pendulum appliance in Class II patients at varying stages of den tal development and with varying facial patterns (high, neutral, and low ma ndibular plane angles). Specifically, the amount and nature of the "distali zation" of the maxillary first molars and the reciprocal effects on the anc horing maxillary first premolars and incisors were studied, as were skeleta l changes in the sagittal and vertical dimensions of the face. Pretreatment and posttreatment cephalometric radiographs obtained from 13 practitioners were used to document the treatment of 101 patients (45 boys and 56 girls) . The average maxillary first molar distalization was 5.7 mm, with a distal tipping of 10.6 degrees, The anchoring anterior teeth moved mesially, as i ndicated by the 1.8-mm anterior movement of the upper first premolars, with a mesial tipping of 1.5 degrees, The maxillary first molars intruded 0.7 m m, and the first premolars extruded 1.0 mm. Lower anterior facial height in creased 2.2 mm; there was no significant difference in lower anterior facia l height increase between patients of high, neutral, or low mandibular plan e angles. In patients with erupted maxillary second molars, there was a sli ghtly greater increase in lower anterior face height and in the mandibular plane angle and a slightly greater decrease in overbite in comparison to pa tients with unerupted second molars. Similar findings were observed in pati ents with second premolar anchorage versus those with second deciduous mola r anchorage. The results of this study suggest that the pendulum appliance is effective in moving maxillary molars posteriorly during orthodontic trea tment. For maximum maxillary first molar distalization with minimal increas e in lower anterior facial height, this appliance is used most effectively in patients with deciduous maxillary second molars for anchorage and unerup ted permanent maxillary second molars, although significant bite opening wa s not a concern in any patient in this study.