Occlusal Plane Changes After Molar Distalization With a Pendulum Appliance in Growing Patients with Class II Malocclusion: A Retrospective Cephalometric Study

Turk J Orthod. 2021 Feb 23;34(1):10-17. doi: 10.5152/TurkJOrthod.2021.20050. eCollection 2021.


Objective: This study aimed to evaluate the skeletal and dental changes after distalization with a pendulum appliance in growing patients with Class II malocclusion, focusing on the occlusal plane (OP).

Methods: The sample included 24 patients with Class II malocclusion (10 boys, 14 girls); their mean age was 12.1 years. All patients underwent molar distalization and had 2 serial cephalograms traced at baseline (T1) and after distalization (T2). Angular and linear dental changes were calculated by taking the sella-nasion (SN), palatal plane (PP), and pterygoid vertical as reference. OP inclination was compared with SN, PP, and mandibular plane. The collected data were computed for all the tested variables, and one-way paired t-test was used to assess the significance of the differences between the time points. α was set at 0.05. Multiple linear regressions were used to predict the OP changes.

Results: The mean total treatment time was 8±2 months to obtain a super Class I molar relationship. In T1-T2 interval, statistically significant incisor buccal tipping of 5°±3.6° (p<0.05), first molar distal tipping of 8.9°±8.3° (p<0.001), and second molar tipping of 8.2°±8.1° (p<0.001) were observed. The maxillary first and second molars moved significantly backward by 2.8±3.2 mm (p<0.05) and 3.7±2.7 mm (p<0.001), respectively. Only the premolars showed a statistically significant anchorage loss of 2.7±3.3 mm (p<0.05); overjet increased significantly at 1.3±1.2 mm (p<0.05). Regarding the OP, none of the tested variables showed any statistically significant changes between T1-T2.

Conclusion: The pendulum appliance showed efficacy in distalizing the maxillary first and second molars at the expense of anterior anchorage loss. The OP did not show statistically significant changes after molar distalization.

Keywords: Cephalometry; Class II Angle malocclusion; molar distalization; occlusal plane; pendulum appliance.