The Effects of the Modified Twinblock Appliance Combine Maxillary Protraction in The Treatment of Different Age Angle Patients

Objective:To investigate the soft and hard tissue changes of class patients treated with the modified Twinblock appliance combine maxillary protraction.Methods:Thirty patients were divided into primary dentition group and mixed dentition groups.All patients were treated with the modified Twinblock appliance combine maxillary protraction.Cephalometric analysis were performed with all patients before and after.Results:The statistical analysis showed that SNA,SNB,ANB,A-SFH,PG-SFH of primary dentition and mixed dentition group had significent changes.SNA of primary dentition increased by 2.32°.In mixed dentition group inceased by 2.82°.There were also significent inceased in MP-SN,inmixed dentition group inceased by 2.64°.The change of UI-SN、LI-mp in pramiry dention group had no great change.Conclusion:The modified Twinblock appliance combine maxillary protraction can be used Angle Ⅲ malocclusion in primary dentition and early mixed dentition.But it can not be used in hypodivergent patients and temporomandibular joint dysfunction.