Evaluation of the dentoskeletal effects of maxillary molar distalization with clear aligners: Class II elastics vs. miniscrew anchorage

Background: To compare (1) the dentoskeletal effects of Class II elastics and infrazygomatic crest (IZC) miniscrew anchorage in sequential maxillary molar distalization using clear aligners and (2) the planned and achieved tooth movements of the maxillary molars and second premolars. Methods: A total of 22 patients with Angle Class II malocclusion treated with clear aligners and maxillary molar distalization were included. The patients were divided into two groups based on anchorage method: Class II elastics or IZC miniscrew. Lateral cephalometric radiographs and digital models were obtained from all patients before treatment (T0) and after distalization of the second premolars (T1) to assess skeletal and dental changes. Geomagic Control X was used to superimpose the digital models to evaluate dental movements. Results: Comparison of cephalometric measurements demonstrated significant differences between the groups in incisor mandibular plane angle (IMPA) and overbite. In the intermaxillary elastic group, the upper second molar was distalized by 1.72 ± 0.64 mm, upper first molar by 1.87 ± 0.78 mm, and upper second premolar by 1.55 ± 0.8 mm. In the IZC miniscrew group, the upper second molar was distalized by 2.24 ± 0.87 mm, upper first molar by 2.19 ± 0.74 mm and upper second premolar by 1.84 ± 0.71 mm. In both groups, greater than predicted maxillary molar intrusion was observed. Conclusions: More distal movement of the maxillary second molar was achieved with miniscrews than intermaxillary elastics. In cases where overbite reduction and control of lower incisor inclination are critical, miniscrew anchorage is more advantageous during maxillary molar distalization with clear aligners. Clinical Trial Registration: The study was registered with ClinicalTrials.gov as: NCT06631131.

Class II malocclusion; Clear aligner; Distalization; Miniscrew anchorage

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