Comparative evaluation of the skeletal, dental, and soft-tissue effects of twin block, monoblock, and invisalign mandibular advancement appliances

The aim of this study was to evaluate and compare the skeletal, dental, and soft-tissue effects of the Twin Block, Monoblock, and Invisalign Mandibular Advancement (Invisalign MA) appliances used for functional treatment in individuals with skeletal Class II malocclusion. The study included 45 individuals in the S–MP3cap stage of growth and development who were treated with Monoblock ( n = 15), Twin Block ( n = 15), or Invisalign MA ( n = 15) appliances. Lateral cephalometric radiographs were obtained before functional treatment (T0) and after treatment (T1). A total of 29 measurements were used to assess changes in the dental, skeletal, and soft tissues. Across all treatment groups, significant decreases were observed in ANB°, Wits appraisal, overjet, overbite, and skeletal and soft-tissue convexity angles; similarly, significant increases were identified in SNB°, Co–Gn (mm), Pg–Na Perp, FMA°, GoGn–SN°, LFH/TFH, L1–NB°, IMPA°, and the nasolabial angle throughout the treatment period. No statistically significant differences were found among the groups regarding the changes observed in the soft tissues. The Invisalign MA group showed less increase in vertical parameters than the other groups. Maxillary incisor inclinations decreased more significantly in the Invisalign MA group. Mandibular incisor inclination changes were similar between Monoblock and Invisalign MA groups but greater in the Twin Block group. Maxillary molar eruption was comparable between Invisalign MA and Monoblock groups, while Twin Block showed a more pronounced increase. Finally, mandibular advancement angles were similar across all groups.