title: Torque control during lingual anterior retraction without posterior appliances.
abstract: OBJECTIVE
  To evaluate the factors that affect torque control during anterior retraction when utilizing the C-retractor with a palatal miniplate as an exclusive source of anchorage without posterior appliances.
  
  
  METHODS
  The C-retractor was modeled using a 3-dimensional beam element (0.9-mm-diameter stainless-steel wire) attached to mesh bonding pads. Various vertical heights and 2 attachment positions for the lingual anterior retraction hooks (LARHs) were evaluated. A force of 200 g was applied from each side hook of the miniplate to the splinted segment of 6 or 8 anterior teeth.
  
  
  RESULTS
  During anterior retraction, an increase in the LARH vertical height increased the amount of lingual root torque and intrusion of the incisors. In particular, with increasing vertical height, the tooth displacement pattern changed from controlled tipping to bodily displacement and then to lingual root displacement. The effects were enhanced when the LARH was located between the central and lateral incisors, as compared to when the LARH was located between the lateral incisors and canines.
  
  
  CONCLUSIONS
  Three-dimensional lingual anterior retraction of the 6 or 8 anterior teeth can be accomplished using the palatal miniplate as the only anchorage source. Using LARHs at different heights or positions affects the quality of torque and intrusion.
authors.affiliation: Division of Orthodontics, Department of Dentistry, The Catholic University of Korea, College of Medicine, Seoul, Korea.
authors.forename: Sung-Seo
authors.initials: SS
authors.lastname: Mo
authors.forename: Seong-Hun
authors.initials: SH
authors.lastname: Kim
authors.forename: Sang-Jin
authors.initials: SJ
authors.lastname: Sung
authors.forename: Kyu-Rhim
authors.initials: KR
authors.lastname: Chung
authors.forename: Yun-Sic
authors.initials: YS
authors.lastname: Chun
authors.forename: Yoon-Ah
authors.initials: YA
authors.lastname: Kook
authors.forename: Gerald
authors.initials: G
authors.lastname: Nelson
keywords: Anchorage; C-retractor; Lingual; Miniplate