Optical data acquisition for computer-assisted design of facial prostheses.
OBJECTIVE
The conventional impression technique for manufacturing facial prostheses has the disadvantage of deforming the soft tissues because of the tension caused by the impression material, as well as causing discomfort to the patient. The purpose of this study was to establish a system that allows contact-free reproduction of the facial surface combined with computer-assisted design and fabrication of facial prostheses.


METHODS
Three-dimensional data of the facial surface were obtained using an optical acquisition system based on the method of phase-measuring profilometry. A sensor head with a fringe projector and two CCD cameras for photogrammetric triangulation were used in connection with a PC for measurement control and data evaluation. Software for computer-assisted design of the facial surface to be reconstructed was developed. A prototype facial prosthesis was fabricated using stereolithography. The system was tested using a modified puppet head. First clinical tests were performed with a patient who had undergone maxillofacial surgery including the resection of one eye.


RESULTS
Three-dimensional data acquisition and imaging allow visualization of a whole face without causing tension or neuromuscular reaction. As surface brightness is also part of the digital model, it is even more realistic than a plaster cast. The stereolithographic object showed good marginal fit and satisfactory shape.


CONCLUSIONS
The presented technique allows three-dimensional data reproduction of the facial surface, computer-assisted design of a facial prosthesis, and transfer to a rapid prototyping unit. The system has obvious advantages over conventional impression techniques. Further clinical trials are planned to evaluate the clinical success of the technique.
Runte
Christoph
C
Department of Prosthodontics, Center for Dental Medicine, University of Münster, Waldeyerstrasse 30, D-48149 Münster, Germany. crunte@uni-muenster.de
Dirksen
Dieter
D
Deleré
Holger
H
Thomas
Carsten
C
Runte
Bettina
B
Meyer
Ulrich
U
von Bally
Gert
G
Bollmann
Friedhelm
F
D017076:Computer-Aided Design; D005145:Face / Q000033:anatomy & histology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008447:Maxillofacial Prosthesis; D010363:Pattern Recognition, Automated; D011474:Prosthesis Design / Q000379:methods*