The Effects of Elastic Size and Archwire Type on 3-Dimensional Force Systems When Using Class II Interarch Elastics

• Author / Creator

  Stanley, Joseph C

• Abstract Objectives: An orthodontic simulator (OSIM) device was used to compare the force systems generated by class II elastics on a ½ cusp class II malocclusion using four combinations of two elastic types and two archwire types. Methods: 3-dimensional forces and moments due to class II elastics were measured individually for each tooth (7-7) using Damon Q brackets on the maxillary and mandibular arches. Four test groups (n=44) were compared, each of a different combination of two elastic types (3/16", 2oz and 4.5oz) and two archwire types (0.014" nickel titanium and 0.019" x 0.025" stainless steel). Results: Only the upper canines and lower first molars recorded clinically significant forces (0.3N) and moments (5Nmm). 2oz and 4.5oz class II elastics produced clinically significant vertical extrusive forces and horizontal forces along the archwire to normalize a class II malocclusion. Stainless steel archwire minimized the extrusive forces of the 4.5oz elastics compared to nickel titanium archwire Conclusions: 2oz and 4oz class II elastics produced clinically significant vertical extrusive forces and horizontal forces along the archwire. Archwire type had no effect on 2oz class II elastics whereas 0.019" x 0.025"stainless steel significantly reduced the vertical extrusive effects of the larger 4.5oz elastics.

• Subjects / Keywords

  • Force
  • Orthodontics
  • Class II elastics

• Graduation date

  Spring 2017

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3F766K4M

• 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.