Initial forces experienced by the anterior and posterior teeth during dental-anchored or skeletal-anchored en-masse retraction in an in vitro dental arch

• Author / Creator

  Lee, David W

• Objectives: To evaluate the initial forces generated by retraction springs during en-masse retraction space closure on a simulated maxillary dental arch. To compare these initial retraction forces on the anterior and posterior teeth between traditional dental-anchorage and skeletal anchorage. Methods: A simulated dental arch (OSIM) measured forces and moments in 3-dimensions acting on each tooth generated by retraction springs used for en-masse retraction space closure. Three treatment groups were compared that represented 1) traditional dental-anchorage, 2) skeletal anchorage, 3) skeletal anchorage with power arms. Results: Dental anchorage produced the largest protraction forces on the posterior teeth of 1.77 ± 0.10N. Skeletal anchorage reduced protraction forces to 0.05 ± 0.08N and 0.01 ± 0.02N, without and with power arms respectively. The anterior teeth segment experienced the least vertical forces in the dental-anchored group 0.01 ± 0.07N. Skeletal anchorage increased vertical forces to 0.98 ± 0.70N. The addition of power arms created 0.57 ± 0.11N of vertical force, between the dental-anchored and the skeletal-anchored without power arms groups. Retraction forces on the anterior teeth segment were similar between the dental-anchored and skeletal-anchored groups at 2.99 ± 0.27N and 3.05 ± 0.14N. The addition of power arms to skeletal-anchorage increased retraction forces to 3.30 ± 0.30N. Conclusions: Skeletal anchorage significantly reduced protraction forces on the posterior teeth but significantly increased vertical forces on the anterior teeth. The addition of power arms during skeletal-anchorage reduced the increase in vertical forces on the anterior teeth but was still greater than dental-anchored vertical forces.

• Subjects / Keywords

  • Initial forces
  • Space closure
  • Orthodontic
  • En-masse retraction

• Graduation date

  Spring 2017

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3WM14588

• 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.