Development of a standardized testing system for orthodontic sliding mechanics.

Background: The primary objective of this study was to develop a computer-controlled three-dimensional friction measuring system, the orthodontic friction simulator (OFS). A clinically-based in vitro experiment considering wet and dry friction for conventionally and self-ligated brackets is presented to elucidate debate surrounding sliding mechanics and illustrate capabilities of the OFS.

Methods: The OFS was designed and manufactured using sound engineering principles and with the primary concern of being able to measure all forces and moments generated during sliding mechanics.

Comparison of the detection of subtle changes in myocardial regional systolic function using qualitative and semi-quantitative techniques.

Purpose: To evaluate qualitative wall motion assessment vs. quantitative wall thickening for the assessment of subtle changes in myocardial systolic function using cine MRI.

Methods: Cine MR images were obtained in 5 canines with a significant coronary artery stenosis and in 2 controls on a 1.