Accuracy of machine milling and spark erosion with a CAD/CAM system.
A method for manufacturing crowns and fixed partial dentures based on CAD/CAM has been developed as an alternative to the lost wax technique and the casting of an alloy. In this process two steps are included: milling and spark erosion. The computer-assisted design (CAD) relies heavily on the accuracy of the milling and spark erosion processes to achieve a clinically acceptable restoration. These two processes must be able to produce the crown data generated in the CAD files. This study evaluated the accuracy of the Procera CAD/CAM system in creating specific geometric bodies that were compared with the known dimensions in the CAD files for these bodies. The manufacturing errors of milling (ellipse +/- 6.5 microm, square +/- 3.4 microm, and cylinder +/- 5.8 microm) and spark erosion (ellipse +/- 8.6 microm and square +/- 10.4 microm) were determined. The accuracy of this manufacturing process demonstrated that this system was capable of producing a crown with a clinically accepted range for marginal opening gap dimension of less than 100 microm.
Andersson
M
M
Nobel Biocare, AB Procera Business Area, Göteborg, Sweden.
Carlsson
L
L
Persson
M
M
Bergman
B
B
D000704:Analysis of Variance; D017076:Computer-Aided Design; D003442:Crowns; D003775:Dental Polishing / Q000379:methods / Q000592:standards*; D017267:Dental Prosthesis Design / Q000379:methods / Q000592:standards*; D003830:Denture, Partial, Fixed; D004566:Electrodes; D004572:Electrolysis; D006801:Humans; D008669:Metallurgy / Q000592:standards; D015203:Reproducibility of Results; D014025:Titanium
D014025:Titanium