Dentoskeletal effects of the fast-back molar distalizer followed by fixed appliances

IntroductionThe purpose of this study was to analyze the skeletal and dentoalveolar changes induced by the Fast-Back appliance followed by fixed appliances when compared with untreated Class II controls.Materials and methodsThe treated and untreated samples consisted of 27 subjects each (16 girls and 11 boys in the Fast-Back Group, FBG; 15 girls and 12 boys in the control Group, CG) with mean ages at the start of treatment of 13 years 3 months in the FBG and 13 years 2 months in the CG. Subjects of the FBG were treated during either the pubertal or postpubertal periods. Lateral cephalograms were analyzed at 2 observation periods: before distalization (T1) and after comprehensive orthodontic treatment appliance (T2). The T1-T2 changes in the FBG were contrasted with those in the CG by means of Mann-Whitney U test (p<0.05).ResultsTreatment induced an average correction of molar relationship of 2.4 mm. The significant correction of the overjet (2.1 mm) was associated with a significant amount of lower incisor proclination (3.8 degrees). A significant extrusion of lower molars (1.8 mm) was recorded in the FBG. The FBG showed also a significant increase in total mandibular length (Co-Gn, 2.6 mm), a counterclockwise rotation of the palatal plane (1.4 degrees), an increase in anterior facial height (N-Me, 2.7 mm), and in mandibular ramus height (Co-Go, 2.6 mm).ConclusionsThe Fast-Back is an effective appliance for Class II correction during the pubertal or postpubertal periods.