ABSTRACT
Objective:To study the dental and skeletal changes after orthodontic treatment for malocclusion patients with rapid maxil-lary and mandibular expansion companied with fixed appliance.Methods:36 patients underwent the treatment with rapid maxillary and mandibular expansion companied with straight wire appliance.Pre-and post-treatment dental casts and lateral cephalometric radiographs were measured and compared.Results:After treatment,the maxillary and mandibular arch width perimeters increased(P 0.05).U1-SN and U1-NA decreased,L1-MP and L1-NB increased(P <0.05).Conclusion:Dental crowding can be solved effectively and occlusion re-lationship can be kept well with rapid maxillary and mandibular expansion companied with straight wire appliance without influence on the vertical skeletal relationship.