Comparison of direct and indirect skeletal anchorage for maxillary molar distalization in Class II malocclusion: A prospective clinical study.

Abstract

Background: To compare the dentoalveolar and skeletal changes induced by the direct bone-anchored pull distal slider (PDS) and the indirect bone-anchored dual force distalizer (DFD) in Class II malocclusion patients.

Materials and methods: Twenty subjects (mean age: PDS = 12.8 ± 0.9 years, DFD = 12.9 ± 1 years) were randomly assigned to either the PDS or DFD group. Both appliances employed temporary skeletal anchorage devices to achieve molar distalization. Lateral cephalometric radiographs and dental casts were analyzed before (T1) and after (T2) treatment to evaluate skeletal and dental effects.

Results: Both devices successfully distalized the maxillary first molars (PDS = 7 ± 1 months, DFD = 9 ± 2 months). The distalization amounts were not significantly different (P = 0.339). However, the PDS group exhibited minimal distal tipping (1.75° ± 0.63°, P < 0.001), while the DFD group showed mesial tipping (2.27° ± 5.37°, P = 0.270). The PDS group demonstrated significant maxillary incisor retroclination (-3.21° ± 0.99°, P < 0.001), whereas the DFD group exhibited significant proclination (2.95° ± 1.83°, P = 0.003) and mesial movement (0.91 ± 0.51 mm, P = 0.001). Additionally, the PDS group experienced spontaneous distal premolar drifting, while the DFD group showed mesial movement and tipping of the premolars.

Conclusion: Both PDS and DFD effectively distalized maxillary molars, but the PDS provided better control by minimizing tipping and anchorage loss, while the DFD caused anterior anchorage loss.