The effects of stainless steel ligature ties on the mechanical characteristics of conventional and self-ligated brackets subjected to torque

  • Author / Creator
    Al Fakir, Hussam
  • Stainless steel ligatures ties are routinely used by orthodontists to improve torque; nevertheless, there is a lack of evidence as to the role of stainless steel ligation in bracket retentive characteristics. The objective of this study is to look into the effects of stainless steel (SS) ligation has on torque and bracket deformation for conventional and self-ligated brackets. A previously described torquing apparatus, combined with an overhead camera, utilized to rotate a .019x.025-inch stainless steel wire in a bracket slot to measure torque (Nmm) and acquire an overhead image at 3° increments of wire rotation from 0° up to 45°, and back again to 0°. A digital image correlation means and two profile images comparisons (before and after) were used to assess the structural changes of the bracket throughout the wire rotation and after the experiment, respectively Sixty Orthos®Twin brackets (Ormco Corp., Glendora, CA, USA), 30 ligated with conventional elastic ties and 30 ligated with SS ligature ties, and sicty Damon Q® brackets (Ormco Corp., Glendora, CA, USA), 30 ligated with its conventional sliding door and 30 ligated with SS ties in addition to the sliding door, were used. The torque was significantly higher for the steel ligated groups over conventional ones from 3°-9° of wire rotation. Overall, steel ligation did increase torque for Orthos twin brackets but it did not for Damon Q brackets. Stainless steel ligature reduces the amount of plastic deformation of both Orthos twin and Damon Q brackets, and a slight decrease in the slot width can be evident when stainless steel ligature is first applied to a bracket. SS ligature ties can be an effective auxiliary tool that could help practitioners to achieve better torque and to reduce bracket deformation

  • Subjects / Keywords
  • Graduation date
    Fall 2012
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
  • Institution
    University of Alberta
  • Degree level
  • Department
  • Specialization
    • Orthodontics
  • Supervisor / co-supervisor and their department(s)
  • Examining committee members and their departments
    • Giseon Heo (Department of Dentistry)
    • David Nobes (Mechanical Engineering)
    • Paul Major (Department of Dentistry)
    • Jason Carey (Mechanical Engineering)