title: Displacement pattern of the anterior segment using antero-posterior lingual retractor combined with a palatal plate.
abstract: OBJECTIVE
  To evaluate and compare the effects of two appliances on the en masse retraction of the anterior teeth anchored by temporary skeletal anchorage devices (TSADs).
  
  
  METHODS
  The sample comprised 46 nongrowing hyperdivergent adult patients who planned to undergo upper first premolar extraction using lingual retractors. They were divided into three groups, based on the lingual appliance used: the C-lingual retractor (CLR) group (group 1, n = 16) and two antero-posterior lingual retractor (APLR) groups (n = 30, groups 2 and 3). The APLR group was divided by the posterior tube angulation; posterior tube parallel to the occlusal plane (group 2, n = 15) and distally tipped tube (group 3, n = 15). A retrospective clinical investigation of the skeletal, dental, and soft tissue relationships was performed using lateral cephalometric radiographs obtained pretreatment and post en masse retraction of the anterior teeth.
  
  
  RESULTS
  All groups achieved significant incisor and canine retraction. The upper posterior teeth did not drift significantly during the retraction period. The APLR group had less angulation change in the anterior dentition, compared to the CLR group. By changing the tube angulation in the APLR, the intrusive force significantly increased in the distally tipped tube of group 3 patients and remarkably reduced the occlusal plane angle.
  
  
  CONCLUSIONS
  Compared to the CLR, the APLR provides better anterior torque control and canine tipping while achieving bodily translation. Furthermore, changing the tube angulation will affect the amount of incisor intrusion, even in patients with similar palatal vault depth, without the need for additional TSADs.
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: Soon-Yong
authors.initials: SY
authors.lastname: Kwon
authors.affiliation: Department of Orthodontics, School of Dentistry, Kyung Hee University, Seoul, Korea.
authors.forename: Kyung A
authors.initials: KA
authors.lastname: Kim
authors.affiliation: Department of Orthodontics, School of Dentistry, Kyung Hee University, Seoul, Korea.
authors.forename: Ki-Ho
authors.initials: KH
authors.lastname: Park
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, School of Dentistry, Kyung Hee University, Seoul, Korea.
authors.forename: Hyo-Won
authors.initials: HW
authors.lastname: Ahn
authors.affiliation: Division of Orthodontics, Department of Orofacial Science, University of California San Francisco, San Francisco, CA, USA.
authors.forename: Gerald
authors.initials: G
authors.lastname: Nelson
keywords: C-lingual retractor; Intrusion; Lingual orthodontics; Mini-implant