Purpose: To compare changes of hard tissues before and after treatment of functional and skeletal Angle Class Ⅲ malocclusion with FRⅢ appliance.
Methods: Thirty patients with functional and skeletal Angel Class Ⅲ malocclusion were selected and treated with FRⅢ appliance. SPSS 22.0 software package was performed for statistical analysis.
Results: After treatment, there was no significant difference in SNA, S-Ptm, ANS-Ptm and Go-Po (P>0.05). ANB, ANS-Me, ANS-Me /N-Me were increased significantly (P<0.01). SNB, L1-NB, L1-MP were decreased significantly (P<0.05). MP-FH, Y axis, U1-NA, U1-NA (mm), U1-SN were increased significantly (P<0.05).
Conclusions: After FRⅢ appliance treatment of Angel Class Ⅲ malocclusion, the position of mandible may rotate clockwise downward and backward， with retrusion of the lower incisors and protrusion of the upper incisors.