The effects of the Pendulum distalising appliance and cervical headgear on the dentofacial structures

Background: Headgears are effective in distalising maxillary molars, but success depends on patient compliance and tolerance. Intra-oral distalising appliances are simple to construct and use and may be a better alternative for patients who are non-compliant or cannot tolerate headgear. Aims: To compare the Pendulum (PEN) appliance and cervical headgear (CHG) on distal movement of maxillary first molars in patients requiring maxillary molar distalisation. Methods: Thirty patients were randomly divided into two groups. Both groups had comparable occlusal and cephalometric characteristics before treatment. Fifteen patients (9 girls, 6 boys) with a mean age of 11.45 1.54 years (Range: 8.58-13.50 years) were treated with Pendulum appliances and 15 patients (10 girls, 5 boys) with a mean age of 11.72 1.24 years (Range: 9.58-13.33 years) were treated with a Ricketts-type CHG. A pilot study of four patients estimated that the time required to distalise the maxillary molars with the Pendulum appliance was five months. Therefore, the end of treatment records for the CHG group were taken after 4.96 0.35 months. Lateral and postero-anterior cephalometric radiographs were taken of both groups at the start (T1) and end of distalisation/treatment (T2). Changes in cephalometric measurements in the two groups were compared with Wilcoxon and Mann-Whitney U tests. Results: Measurements indicated that U6-ANS distance, overjet and U1-APo distance increased, U6-PP angle and U6-PTV distance reduced, and the molar relationship improved more in the PEN group compared with the CHG group. Statistically, significant right molar - left molar differences were found between the two groups. Distalisation produced significant side effects, resulting in distal tipping of the first molars and an increase in overjet, whereas the CHG reduced the overjet. Conclusion: The Pendulum appliance was more effective than the CHG in distalising the maxillary first molars.