Construction and Production of an Implant

The construction of an implant is carried out with the aid of a 3D CAD* system in several steps:  
Step 1
The implant was designed using skull data extracted from an MRI image. The image consists of some 23,000 pixels reproducing the inner and outer skull surfaces in three dimensions (Fig. 1).
Step 2
These pixels are automatically joined to form triangles. The sum of these surfaces yields a virtual replica of the skull as a wireframe model (Fig. 2).
Step 3
The area of the skull needed for the implant is cut out (Fig. 3).
Step 4
A contact surface is created which contains all of the cut-out points. This surface is used as a base for the actual implant construction (Fig. 4).
Step 5
The contours corresponding to the functional units of the implant are added to the base (Fig. 5).
Step 6
Additional surfaces are constructed on the contours and combined to create a virtual mold for the implant. The contours created by the polygon primitives are rounded to prevent the formation of sharp edges that could damage the tissue (Figs. 6, 7, 8). 
Step 7
In the last step, holes are bored and cavities are defined (Fig. 9).
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The production of the implant is prepared with a CAM** system and carried out with a 5-axis CNC system allowing the milling machine to be positioned at various angles with the greatest precision (tolerance < 0.01 millimeters).  
The actual production consists of two steps:
Step 1
Rough shaping of the form with the highest possible speed.
Step 2
Fine finishing for the smoothest possible surface and best fit of the implant.
  * CAD: Computer-aided design
** CAM: Computed-aided manufacturing