Introduction: To three-dimensionally analyze the skeletal and pharyngeal airway changes induced by Twin Block (TWB) and Forsus Fatigue Resistance Device (FFRD) in skeletal Class II female patients compared with untreated controls.
Materials and methods: The study comprised 62 growing female patients with skeletal Class II malocclusion due to mandibular retrusion treated with either TWB (n = 23) or FFRD (n = 21), or neither (n = 18; controls). Pre- and posttreatment/observational cone beam computed tomography images were used to evaluate the treatment changes.
Results: TWB induced more obvious mandibular skeletal changes and caused significant retrusive effects on the maxilla. Similarly, the sagittal and vertical jaw relationships were affected more obviously with TWB (P <0.001) compared to FFRD. Changes in oropharyngeal volume and minimal axial area were more obvious with TWB.
Discussion: The TWB functional appliance induced significant skeletal and pharyngeal airway changes. These changes were more obvious relative to the slight changes induced by FFRD or by natural growth.
Keywords: Cone-beam computed tomography; Functional appliance; Mandibular skeletal changes; Pharyngeal airway; Twin Block.