RESUMO
Objective:To compare the effects of treatment with Hybrid-Hyrax-Facemask(FM)versus miniscrews in the anterior pal-ate combined with Hybrid-Hyrax-Facemask(MSI/FM)for patients with early Class Ⅲ malocclusion and maxillary deficiency.Methods:18 patients aged with early Class Ⅲ malocclusion and maxillary deficiency were randomly divided into 2 groups(n=9)and treated with FM and MSI/FM respectively.Alternating rapid maxillary expansion and constriction(Alt-RAMEC)protocol combined with a maxillary protraction force of 3.92 N was applied on each side of all patients from elastics connected to the facemask in a down-ward and forward direction of 30° to the occlusal plane.Iortho cephalometric software was used to analyze the data of lateral cephalo-grams of the patients before(T0)and after(T1)treatment.Results:Improvement was verified in the facial profile and occlusion of all patients.In MSI/FM group the average treatment time was shorter.There were significant differences(P＜0.05)between T0 and T1 in the following measurements in FM group:SNA,ANB,Co-A,Co-Gn,Wits,S-Go,Na-Me,MP,U1-SN,UADH,LADH,Overjet,UL-EP increased,U1-L1 decreased.There were significant differences(P＜0.05)between T0 and T1 in the following measurements in the MSI/FM group:SNA,ANB,Co-A,Wits,Na-Me,MP,Y-axis,U1-SN,Overjet,UL-EP increased,SNB,Co-Gn-Co-A,S-Go/N-Me,U1-L1,L1-MP decreased.Conclusion:Both FM and MSI/FM combined with Alt-RAMEC protocol and a maxillary protraction force are effective in the treatment for Class Ⅲ patients with maxillary deficiency.MSI/FM may produce more significant bone effect and re-duce dental compensation,promote more forward growth of midface and more improvement in the growth direction of mandible and re-duce compensatory lip inclination of anterior teeth in shorter treatment time.