Application of laser measuring, numerical simulation and rapid prototyping to titanium dental castings.
OBJECTIVE
This paper describes a method of making titanium dental crowns by means of integrating laser measuring, numerical simulation and rapid prototype (RP) manufacture of wax patterns for the investment casting process.


METHODS
Four real tooth crowns (FDI No. 24, 25, 26, 27) were measured by means of 3D laser scanning. The laser digitized geometry of the crowns was processed and converted into standard CAD models in STL format, which is used by RP systems and numerical simulation software. Commercial software (MAGMASOFT) was used to simulate the casting process and optimize the runner and gating system (sprue) design. RP crowns were 'printed' directly on a ModelMaker II 3D Plotting System. A silicone negative mold (soft tool) was made from the RP crowns, then more than hundreds wax crowns were duplicated. The duplicated crowns were joined to the optimized runner and gating system. By using the investment casting process 20-25 replicas of each crown were made on a centrifugal casting machine. All castings were examined for porosity by X-ray radiographs.


RESULTS
By using the integrated scanning, simulation, RP pattern and casting procedure, cast crowns, free of porosity, with excellent functional contour and a smooth surface finish, were obtained from the first casting trial.


CONCLUSIONS
The coupling of laser digitizing and RP indicates a potential to replace the traditional 'impression taking and waxing' procedure in dental laboratory, with the quality of the cast titanium prostheses also being improved by using the numerically optimized runner and gating system design.
Wu
M
M
Foundry Institute, University of Technology Aachen, Intzestr.5, D-52072, Aachen, Germany. menghuai@gi.rwth-aachen.de
Tinschert
J
J
Augthun
M
M
Wagner
I
I
Schädlich-Stubenrauch
J
J
Sahm
P R
PR
Spiekermann
H
H
D002133:Calcium Sulfate; D003198:Computer Simulation; D017076:Computer-Aided Design; D003442:Crowns; D003734:Dental Casting Investment / Q000737:chemistry; D003735:Dental Casting Technique / Q000295:instrumentation; D003764:Dental Materials; D017267:Dental Prosthesis Design; D006801:Humans; D021621:Imaging, Three-Dimensional; D007834:Lasers; D003765:Models, Dental; D016062:Porosity; D011859:Radiography; D012828:Silicones; D012984:Software; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D019228:Tooth Crown / Q000033:anatomy & histology; D014885:Waxes
D003734:Dental Casting Investment; D003764:Dental Materials; D012828:Silicones; D014885:Waxes; D014025:Titanium; D002133:Calcium Sulfate