• Institution: LOCKSS
LOCKSS

Orthodontic Bracket Manufacturing Tolerances and Dimensional Differences between Select Self-Ligating Brackets

  1. Thomas W. Major tmajor{at}ualberta.ca1
  2. Jason P. Carey jason.carey{at}ualberta.ca1
  3. David S. Nobes david.nobes{at}ualberta.ca1
  4. Paul W. Major major{at}ualberta.ca2
  1. 1Mechanical Engineering, Faculty of Engineering, University of Alberta, Edmonton, AB, Canada, T6G 2G8
  2. 2Orthodontic Graduate Program, Department of Dentistry, Dentistry/Pharmacy Centre, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada, T6G 2N8

Abstract

In all manufacturing processes there are tolerances; however, orthodontic bracket manufacturers seldom state the slot dimensional tolerances. This experiment develops a novel method of analyzing slot profile dimensions using photographs of the slot. Five points are selected along each wall, and lines are fitted to define a trapezoidal slot shape. This investigation measures slot height at the slot's top and bottom, angles between walls, slot taper, and the linearity of each wall. Slot dimensions for 30 upper right central incisor self-ligating stainless steel brackets from three manufacturers were evaluated. Speed brackets have a slot height 2% smaller than the nominal 0.559 mm size and have a slightly convergent taper. In-Ovation brackets have a divergent taper at an average angle of 1.47 degrees. In-Ovation is closest to the nominal value of slot height at the slot base and has the smallest manufacturing tolerances. Damon Q brackets are the most rectangular in shape, with nearly 90-degree corners between the slot bottom and walls. Damon slot height is on average 3% oversized.

  • Received January 8, 2010.
  • Revision received March 26, 2010.
  • Accepted June 3, 2010.
|

This Article

  1. J Dent Biomech vol. 1 no. 1 781321

Share