Three-dimensional skeletal, dentoalveolar, and temporomandibular changes after twin block therapy in growing patients with Class II malocclusion due to mandibular retrusion: influence of treatment timing
Authors
Sabina Saccomanno, Jorida Jubani, Francesca Russo, Elisabetta Guercio Monaco, Mario Palermiti, Giuseppe Marzo
Abstract
Class II malocclusion due to mandibular retrusion is one of the most common dentoskeletal discrepancies in growing patients and a major indication for functional orthopedic therapy. This retrospective cohort study with an untreated control comparison evaluated the three-dimensional skeletal, dentoalveolar, and temporomandibular joint (TMJ) effects of Twin Block therapy and assessed whether treatment timing influenced the magnitude of change. Fifty-four subjects were analyzed: 18 treated in the pre-pubertal stage (ETG), 18 treated in the pubertal stage (LTG), and 18 untreated controls (CG) with comparable baseline Class II characteristics. Treated patients underwent cone-beam computed tomography (CBCT) before treatment (T1) and at the end of functional therapy (T2); control data were obtained from matched radiographic records. Three-dimensional skeletal, dentoalveolar, and TMJ variables were measured using dedicated software; repeatability was assessed with the intraclass correlation coefficient. Both treated groups showed significant mandibular advancement compared with controls, with larger changes in the pubertal group. SNB increased by 1.2° in ETG and 2.3° in LTG, ANB decreased by 1.1° and 2.0° respectively, and Co-Gn increased by 1.9 mm in ETG versus 3.5 mm in LTG. Overjet decreased by 3.8 mm in ETG and 4.1 mm in LTG. Condylar displacement was mainly antero-inferior, without radiologic signs of TMJ degeneration. Twin Block therapy was effective in correcting Class II mandibular retrusion, but the greatest orthopedic response was observed when treatment was performed during the pubertal growth phase.
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