Treatment and posttreatment outcomes induced by the Mandibular Advancement Repositioning Appliance; A controlled clinical study

Objective: To evaluate the treatment and posttreatment dentoskeletal effects induced by the Mandibular Advancement Repositioning Appliance (MARA) in the treatment of Class II malocclusion. Materials and Methods: The treated sample consisted of 23 consecutively treated patients at prepubertal or pubertal stages, as assessed by the cervical vertebral maturation method. A control group of untreated Class II subjects was generated from published normative growth data. Lateral cephalograms were digitized and superimposed via cephalometric software at three different times: T1, pretreatment; T2, post-MARA treatment; and T3, at least 1 year after T2. The T1-T2, T2-T3, and T1-T3 changes in the treated group were compared to those in the control group with independent-sample Student's t-tests. Results: Skeletal and dentoalveolar effects of MARA were assessed after the active phase of the treatment (T1-T2). Mandibular elongation in length (Co-Gn, +2.2 mm) was evident together with lower incisor proclination (IMPA, +5.8 mm). A relapse tendency for IMPA was noticed after removing the appliance (IMPA, -2.1 degrees during T2-T3). Significant skeletal effects (Co-Gn, +2.0 mm) and headgear effects on the maxilla (SNA, -1.2 degrees) were significant in the long term (T1-T3). Conclusions: The MARA appliance provides an effective correction of Class II malocclusion, which is maintained at a posttreatment observation with a moderate skeletal effect. (Angle Orthod. 2011;81:684-691.)