title: [Treatment effects of the maxillary protraction in correction of maxillary deficiency: a comparative study between RPE group and no RPE group.].
abstract: OBJECTIVE
  To compare the clinical effects of rapid palatal expansions combined with maxillary protractions to that of maxillary protractions of the maxillary deficiency alone.
  
  
  METHODS
  Twenty patients aging from 9 to 11 years were divided into two groups , each group had 10 patients. All patients were diagnosed as having deficient maxillas with anterior crossbite. Group A were treated with rapid palatal expansion before maxillary protraction.Group B were treated with maxillary protraction alone. Lateral cephalometric films were taken at the beginning and the end of the treatment, and analyzed with McNamara analysis (Co-A,Co-Gn,ANS-Me) and traditional analysis.
  
  
  RESULTS
  (1) After maxillary protraction,the maxilla and upper dentitions were protracted in both groups,the anterior crossbite had been corrected and obvious profile changes can be observed. (2) The mandible moved backward and downward in the RPE group and more obvious profile changes can be achieved compared with no RPE group.
  
  
  CONCLUSIONS
  (1) It's an effective method to manage the maxillary deficiency with maxillary protraction in the mixed dentition. (2) Applying maxillary protraction combined with RPE is more adaptable to low angle cases.
authors.affiliation: Department of Dentistry,Xiangfan Railway Hospital, Xiangfan 441003, Hubei Province, China. lymzxf@163.com
authors.forename: Yu-mei
authors.initials: YM
authors.lastname: Li
authors.forename: Meng-ping
authors.initials: MP
authors.lastname: Zhang
authors.forename: Nian-bao
authors.initials: NB
authors.lastname: Zha
mesh_terms: D002508:Cephalometry; D002648:Child; D003818:Dentition, Mixed; D006801:Humans; D008310:Malocclusion / Q000175:diagnosis / Q000628:therapy*; D008313:Malocclusion, Angle Class III; D008334:Mandible; D008437:Maxilla; D010155:Palatal Expansion Technique; D014070:Tooth