Background and objective: To evaluate the skeletal and pharyngeal airway effects of skeletal anchored Forsus FRD EZ appliance using bilateral miniplates inserted on mandibular symphyses and to compare the findings with a well matched control group treated using a Herbst appliance. 

Methods: Thirty patients with skeletal Class II malocclusion due to mandibular retrusion were divided into two groups. Group 1 consisted of 15 patients (8 females and 7 males; mean age: 13.11 +/- 1.29 years) treated using the Herbst appliance and Group 2 consisted of 15 patients (9 females and 7 males; 12.84 +/- 1.27 years) treated using the skeletal anchored Forsus FRD EZ appliance. Treatment changes were assessed by means of linear, angular, and area measurements. 

Results: The groups were well matched regarding to the chronological ages, gender distribution and initial cephalometric values (P > 0.05). In both groups, skeletal Class II malocclusion was corrected by decrease in SNA and increase in SNB, Co-Gn, VRL-B and VRL-Pog measurements. Those changes caused a significant correction in the maxillo-mandibular relationship. Upper and lower pharyngeal airway dimensions were increased in both group, while the increase in the lower pharyngeal dimension was found to be statistically significant in the skeletal anchored Forsus FRD EZ group (P < 0.05). Oropharyngeal area measurements significantly increased in both groups (P < 0.001 and P < 0.01, respectively). Comparison of the groups showed that both groups had similar changes with no statistically significant differences (P > 0.05). 

Conclusion: Skeletal changes produced by both appliances caused significant pharyngeal airway changes.