title: Factors controlling anterior torque with C-implants depend on en-masse retraction without posterior appliances: biocreative therapy type II technique.
abstract: BACKGROUND
  Our objective was to evaluate the factors that affect effective torque control during en-masse anterior retraction by using intrusion overlay archwire and partially osseointegrated C-implants as the exclusive sources of anchorage without posterior bonded or banded attachments.
  
  
  METHODS
  Base models were constructed from a dental study model. No brackets or bands were placed on the posterior maxillary dentition during retraction. Different heights of the anterior retraction hooks to the working segment archwire and different intrusion forces with an overlay archwire placed in the 0.8-mm diameter hole of the C-implant were applied to generate torque on the anterior segment of the teeth. The amount of tooth displacement after finite element analysis was exaggerated 70 times and compared with tooth axis graphs of the central and lateral incisors and the canine.
  
  
  RESULTS
  The height of the anterior retraction hook and the amount of intrusion force had a combined effect on the labial crown torque applied to the incisors during en-masse retraction. The difference of anterior retraction hook length highly affected the torque control and also induced a tendency for canine extrusion.
  
  
  CONCLUSIONS
  Three-dimensional en-masse retraction of the anterior teeth as an independent segment can be accomplished by using partially osseointegrated C-implants as the only source of anchorage, an intrusion overlay archwire, and a retraction hook (biocreative therapy type II technique).
authors.affiliation: Division of Orthodontics, Department of Dentistry, Catholic University of Korea, 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: Youn-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
mesh_terms: D000539:Alveolar Process / Q000502:physiology; D001696:Biomechanical Phenomena; D003481:Cuspid / Q000503:physiopathology; D015921:Dental Implants; D003799:Dental Stress Analysis / Q000379:methods; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006801:Humans; D007180:Incisor / Q000503:physiopathology; D008437:Maxilla; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D016382:Orthodontic Appliance Design; D009969:Orthodontic Wires; D016348:Osseointegration; D057887:Overbite / Q000628:therapy*; D010513:Periodontal Ligament / Q000502:physiology; D013314:Stress, Mechanical; D014087:Tooth Movement Techniques / Q000379:methods*; D019415:Torque
chemical_list: D015921:Dental Implants