title: En-masse retraction with a preformed nickel-titanium and stainless steel archwire assembly and temporary skeletal anchorage devices without posterior bonding.
abstract: OBJECTIVE
  To evaluate the therapeutic effects of a preformed assembly of nickel-titanium (NiTi) and stainless steel (SS) archwires (preformed C-wire) combined with temporary skeletal anchorage devices (TSADs) as the sole source of anchorage and to compare these effects with those of a SS version of C-wire (conventional C-wire) for en-masse retraction.
  
  
  METHODS
  Thirty-one adult female patients with skeletal Class I or II dentoalveolar protrusion, mild-to-moderate anterior crowding (3.0-6.0 mm), and stable Class I posterior occlusion were divided into conventional (n = 15) and preformed (n = 16) C-wire groups. All subjects underwent first premolar extractions and en-masse retraction with pre-adjusted edgewise anterior brackets, the assigned C-wire, and maxillary C-tubes or C-implants; bonded mesh-tube appliances were used in the mandibular dentition. Differences in pretreatment and post-retraction measurements of skeletal, dental, and soft-tissue cephalometric variables were statistically analyzed.
  
  
  RESULTS
  Both groups showed full retraction of the maxillary anterior teeth by controlled tipping and space closure without altered posterior occlusion. However, the preformed C-wire group had a shorter retraction period (by 3.2 months). Furthermore, the maxillary molars in this group showed no significant mesialization, mesial tipping, or extrusion; some mesialization and mesial tipping occurred in the conventional C-wire group.
  
  
  CONCLUSIONS
  Preformed C-wires combined with maxillary TSADs enable simultaneous leveling and space closure from the beginning of the treatment without maxillary posterior bonding. This allows for faster treatment of dentoalveolar protrusion without unwanted side effects, when compared with conventional C-wire, evidencing its clinical expediency.
authors.affiliation: Department of Orthodontics, Postgraduate School of Dentistry, The Catholic University of Korea, Seoul, Korea.
authors.forename: Jeong-Hyun
authors.initials: JH
authors.lastname: Jee
authors.affiliation: Department of Orthodontics, School of Dentistry, Kyung Hee University, Seoul, Korea.
authors.forename: Hyo-Won
authors.initials: HW
authors.lastname: Ahn
authors.affiliation: Department of Orthodontics, School of Dentistry, Kyung Hee University, Seoul, Korea.
authors.forename: Kyung-Won
authors.initials: KW
authors.lastname: Seo
authors.affiliation: Department of Orthodontics, School of Dentistry, Kyung Hee University, Seoul, Korea.
authors.forename: Seong-Hun
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Orthodontics, Postgraduate School of Dentistry, The Catholic University of Korea, Seoul, Korea.
authors.forename: Yoon-Ah
authors.initials: YA
authors.lastname: Kook
authors.affiliation: Department of Orthodontics, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Kyu-Rhim
authors.initials: KR
authors.lastname: Chung
authors.affiliation: Division of Orthodontics, Department of Orofacial Science, University of California, San Francisco, CA, USA.
authors.forename: Gerald
authors.initials: G
authors.lastname: Nelson
keywords: Anchorage; Orthodontic mini-implant; Orthodontic treatment; Tooth movement