Fixed vs Removable Twin-block Treatment in Skeletal Class II Malocclusion

Abstract

Aim or Purpose: To compare the skeletal and dental effects of a novel fixed twin-block appliance with the conventional removable twin-block appliance on skeletal class II adolescents. Materials and Methods: Thirty-three adolescents with skeletal class II division 1 malocclusions (14 boys, 19 girls; age, 12.02 ± 1.02 years) were devided into fixed group and removable group. All patients showed anteroposterior discrepancies in the vertebral CVMI-II and CVMI-III stages. Cephalometric analysis was used for assessment. Follow-up data were obtained for 2.1 to 3 years (2.58 ± 0.51 years) post-treatment to assess the stability of treatment. Results: Anteroposterior disharmony between the jaws was corrected by significant condylar growth stimulation (SNB and Pg/OLP+Co/OLP) in both group but more in fixed group. SNA did not show significance of maxillary growth inhibition. In addition to skeletal changes, upper incisor retroclination and mesial movement of the whole lower dentition contributed to correction of the molar relationship in both group. Follow-up data showed the relative stability of this clinical protocol. Conclusions: Correction of skeletal class II malocclusion by fixed twin-block treatment followed by fixed-appliance treatment yielded a combination of skeletal and dentoalveolar changes.