Three-dimensional quantification of color-marked occlusal paths on anatomically oriented casts.
BACKGROUND
The analysis of occlusal contacts on mounted diagnostic casts is an important task in prosthetic diagnostics. However, it is still restricted mainly to qualitative aspects because existing measuring techniques fail to provide 3-dimensional data for more than a few single points in acceptable time.


OBJECTIVE
The aim of this study was to develop a method for quantifying occlusal contacts and paths by using anatomically oriented diagnostic casts and to design the method to allow fast acquisition of digital 3-dimensional coordinates.


METHODS
Plaster casts with color-marked contacts were digitized optically with a profilometric system based on the fringe projection technique. Digital camera images taken simultaneously were used to define the contact areas by marking them either manually or automatically with the help of image-processing routines. Three-dimensional coordinates were determined by finding the corresponding points within the profilometric data set.


RESULTS
Color-marked contact areas on diagnostic casts were successfully digitized with a computer-controlled, automatic setup in approximately 30 seconds. The accuracy of the acquired 3-dimensional data was estimated to be better than 60 microm in lateral and 30 microm in height resolution. The data set was visualized and evaluated in a skull related coordinate system.


CONCLUSIONS
This study verified the use of a new tool to quantify color-marked occlusal contacts on diagnostic casts in terms of spatial coordinates. The resulting digital data may be stored easily and analyzed numerically as well as visualized 3-dimensionally with computer graphic equipment. Because the anatomic orientation of the casts is maintained throughout the measurement process, it is possible to compare the data with electronically registered condyle paths and therefore to investigate, for example, their relation to the corresponding guidance paths of the frontal teeth and the canines in dynamic occlusion.
Dirksen
D
D
Laboratory of Biophysics, Institute of Experimental Audiology, University of Muenster, Muenster, Germany. dirksen@gabor.uni-muenster.de
Runte
C
C
Böröcz
Z
Z
Thomas
C
C
von Bally
G
G
Bollmann
F
F
D003116:Color; D003196:Computer Graphics; D003481:Cuspid / Q000502:physiology; D003725:Dental Articulators; D003766:Dental Occlusion; D004582:Electronics, Medical / Q000295:instrumentation; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional; D007180:Incisor / Q000502:physiology; D007574:Jaw Relation Record / Q000295:instrumentation / Q000379:methods*; D008335:Mandibular Condyle / Q000502:physiology; D003765:Models, Dental; D055095:Optics and Photonics / Q000295:instrumentation