Comparative effects of maxillary total-arch distalization using Class II elastics alone vs miniscrew assistance in nonsurgical adult Class II correction: A retrospective cohort study.
Abstract
INTRODUCTION Although Class II elastics are widely used, evidence on their dentoalveolar effects in adults is limited. This study aimed to radiographically compare the sagittal and vertical dentoalveolar effects of Class II correction using elastics alone vs miniscrew-assisted maxillary total-arch distalization (MTAD), with nighttime vs full-time elastic wear in adults treated with completely customized lingual appliances.
Methods
A total of 79 consecutively treated adult patients with Class II malocclusion were included and grouped by protocol: elastics only (n = 34), MTAD with nighttime elastics (MTAD 7/7; n = 24), and MTAD with full-time elastics (MTAD 24/7; n = 21). Pretreatment (T0) and posttreatment (T1) lateral cephalograms were analyzed using Björk and Skieller superimposition and Pancherz analysis. Intragroup changes were assessed with paired-samples t tests, and intergroup differences were assessed using analysis of variance (α = 0.05).
Results
Treatment time was comparable between groups. Elastics corrected Class II primarily through mandibular molar mesialization (+1.8 mm; 62%) and mandibular incisor advancement (+1.6 mm), with limited maxillary molar distalization (-1.1 mm; 38%). MTAD 7/7 achieved correction mainly through maxillary molar distalization (-3.1 mm; 91%) with minimal mandibular molar mesialization (+0.3 mm; 9%) and reduced mandibular incisor advancement (+0.5 mm). MTAD 24/7 combined both mechanisms (maxillary molar distalization, -3.0 mm; 62.5% and mandibular molar mesialization, +1.8 mm; 37.5%), producing the greatest overall molar correction (4.8 mm). Both MTAD protocols showed significantly greater maxillary molar distalization and intrusion than elastics alone (P <0.001). Vertical changes, including maxillary molar intrusion and mandibular incisor intrusion, contributed to a clockwise rotation of the occlusal plane in all groups.
Conclusions
In nonsurgical adult Class II correction, elastics primarily act on the mandibular dentition, whereas MTAD produces greater maxillary distalization and may reduce dependence on patient compliance.