ABSTRACT
Objective:To observe the effects of the vertical holding appliance (VHA) in the extraction treatment of patients with hyperdivergence.Methods:40 hyperdivergent patients orthodonticly treated by 4 first premolar extraction with(VHA group) and without VHA(control group) (n =20) respectively.Cephalometric radiographs were taken before and after orthodontic treatment and measured digitally by Winceph 8.06 software.Results:After treatment,the L6-MP,S-Go,N-Me,ANS-Me increased in the VHA group(P ＜ 0.05).The MP-SN,Y-axis,U1-PP,U6-PP,L6-MP,S-Go,N-ANS,N-Me,ANS-Me,ANS-Me/N-Me increased and the S-Go/N-Me decreased in the control group(P ＜0.05).The changes of the MP-SN,Y-axis,U6-PP,L6-MP,N-Me,ANS-Me,ANS-Me/N-Me,S-Go/N-Me were smaller in the VHA group than those in the control group (P ＜ 0.05).Conclusion:VHA is effective in the control of the height of molars in the extraction treatment of patients with hyperdivergence.