RESUMEN
<p><b>OBJECTIVE</b>To evaluate the effects of modified Forsus appliance in the treatment of Class II mandibular retrusion.</p><p><b>METHODS</b>18 children with mandibular retrusion were selected and treated with modified Forsus appliance. Cephalometric radiographs were taken and analyzed at pre-treatment and post-treatment. Students' t-test was used to determine if there were significant differences between pre-treatment and post-treatment.</p><p><b>RESULTS</b>After 6-8 months of therapy, profiles were obviously improved. B moved forward (2.9+/-3.1) mm. ANB decreased (2.5+/-1.2) degrees. The overjet decreased (5.0+2.8) mm. The molar relationship was corrected to Class I from Class II. SN-OL increased (4.3+2.2) degrees. There was significant difference between pre-treatment and post-treatment.</p><p><b>CONCLUSION</b>Combined with straight wire appliance, modified Forsus appliance can effectively stimulate the mandibular growth, balance the jaw relationship, and correct mandibular retrusion.</p>