title: [Comparing the anchorage effects of micro-implant and J hook on treating patients with maxillary protrusion].
abstract: OBJECTIVE
  To investigate the differences in anchorage effects between micro-implants and J hook in treating patients with Class II division 1 maxillary protrusion.
  
  
  METHODS
  Thirty-one cases of adult patients with Class II division 1 maxillary protrusion were treated. They were divided into 2 groups depending on their selection. The first group included 17 patients for micro-implant anchorage, who adopted micro-implant and sliding mechanism to close maxillary extraction space and depress the mandibular molar. The second group encompassed 14 cases for J hook, who adopted sliding mechanism, J hooks in high traction and Class II intermaxillary traction to close extraction space. X-ray lateral cephalometric radiographs were measured before and after treatment, and SPSS16.0 software package was employed to compare the differences in soft and hard tissue changes before and after treatment between 2 groups.
  
  
  RESULTS
  There were statistically significant differences in SNB, ANB, MP-FH, U1-Y, U6-Y, L6-MP, NLA, and UL-Y between the 2 groups before and after treatment, while there was no significant difference in SNA, U1-SN, U1-X, and U6-X between the 2 groups.
  
  
  CONCLUSIONS
  In treating patients with Class II division 1 maxillary protrusion, micro-implant has stronger anchorage effects than J hook, while at the same time depressing the mandibular molars, and making it more favorable to improve Class II faces.
authors.affiliation: Department of Stomatology, Qingtian People's Hospital. Qingtian 323900, Zhejiang Province, China.E-mail:qtwuxin@163.com.
authors.forename: Xin
authors.initials: X
authors.lastname: Wu
authors.forename: Guo-yuan
authors.initials: GY
authors.lastname: Liu
authors.forename: Yong-lian
authors.initials: YL
authors.lastname: Jiang
mesh_terms: D000328:Adult; D002508:Cephalometry; D006801:Humans; D007180:Incisor; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D008437:Maxilla; D008963:Molar; D009967:Orthodontic Appliances