RESUMO
INTRODUCTION: Fixed functional appliances have been used to treat Class II malocclusion by a huge number of professionals. This retrospective study aimed to analyze the effects of the Forsus fatigue-resistant device and compare the findings with a well-matched group treated with the mandibular anterior repositioning appliance (MARA). METHODS: The Forsus group was composed of 14 patients at an initial mean age of 12.4 ± 1.3 years, treated with the Forsus fatigue-resistant device followed by a fixed orthodontic appliance. The MARA group comprised 18 patients at an initial mean age of 12.1 ± 1.3 years, treated with MARA followed by fixed orthodontic appliances. The untreated control group consisted of 14 patients matched with the other groups. Posttreatment changes were calculated as T1 - T2. Intergroup comparisons regarding treatment changes were performed using repeated-measures analysis of variance followed by Tukey's test. RESULTS: During treatment, the Forsus group showed a statistically significant decrease in maxillary protrusion and maxillomandibular sagittal discrepancy in the control group. The MARA group showed significantly greater retrusion of maxillary incisors than the Forsus and the control group. Overjet decreased significantly more in the treated groups in relation to the control group. Molar relationship improved significantly more in both treated groups, and both showed more correction than the untreated control group. CONCLUSIONS: The Forsus and MARA associated with fixed appliances effectively corrected the Class II malocclusion, mostly using dentoalveolar changes and maxillary growth restriction.