This investigation is using the helical axis to describe jaw function. Dentistry needs a method to assess jaw function that allows comparisons both between and within individuals. Computer models of the masticatory system exist. However, they are questionable for clinic use because of the time and expense involved in acquiring anatomic data. A promising method to assess jaw function is the helical axis, which describes motion as a rotation about an axis and a translation along this axis. The helical axis provides insight into the relationship between kinematics and joint anatomy, and thus, it can be a helpful diagnostic tool. Also, comparisons are more reliable because the helical axis does not depend on the precise location of anatomical landmarks.
This project is testing the helical axis concept by mapping the movement of models of teeth in an articulator, which simulates jaw motion. The coordinates of 96 anatomical points are being mapped as a function of relative jaw displacement using a three-dimensional digitizer. The paths of motion for these 96 points are being determined by fitting quintic splines to the points. From these curves, the helical axis parameters are calculated and compared to the expected values.
Ching-Chang Ko, Faculty Collaborator
Hongyi Wang, Research Associate
During the past year, this project concentrated on verifying the helical axis algorithms using a computer simulation. Three-dimensional jaw motion was simulated by rotating a three-dimensional digital image of a lower jaw 1° about a helical axis at a known location. The (x,y,z) coordinates of a set of points on the before and after rotation images of the jaw were used to back calculate the helical axis parameters. The predicted parameters were within 1% of the actual parameters. To make the simulation more realistic, a random error of ±100 microns was added to the coordinates of the after rotation set of points. Under these conditions, the agreement was still better than 5%. The results validate the algorithms and verify the concept of using the digital images of the jaws to calculate the location of the helical axis.
|
|
URL: http://www.msi.umn.edu/about/publications/annualreport/ar2000/depts/Dentistry/delong.html |
|
| This page last modified on Friday, 30-May-2008 16:14:01 CDT | ||
| Please direct questions or problems to help@msi.umn.edu | ||
|
Website related questions or problems should be directed to
webmaster@msi.umn.edu
The Supercomputing Institute does not collect personal information on visitors to our website. For the University of Minnesota policy, see www.privacy.umn.edu. © 2001 by the Regents of the University of Minnesota |
||