Recreating ears one at a time
Medical clinic uses subtractive processes to create prosthetic ears.
How do you recreate patients’ ears? “One at a time,” said Allison Vest, MS, an anaplastologist with The Medical Art Prosthetics Clinic in Dallas, Texas. The Clinic specializes in prosthetics for fingers, toes and facial features. Patients afflicted by cancer, congenital conditions, or trauma come to the clinic from all over the country and around the world to obtain highly personalized aesthetic restoration.
Established in 1985, the Medical Art Prosthetics Clinic is a full-service office, clinic and laboratory. Vest joined founder Greg Gion at the clinic in 2004, bringing a balance of artistic talent and medical training as well as a command of digital technologies that are benefitting the field of facial and body restoration.
The clinic recently invested in a Roland MDX-15 scanning/milling machine to assist them with auricular, or ear, restoration. They chose the MDX because of its compact dimensions, easy-to use technology, and capabilities. It scans a wide range of objects including soft objects like clay and fruit. It can even scan glass, a difficult feat because the light beams pass through the object without detecting it. Noted Vest, “I can set the machine to scan overnight, and the next day can let it mill while I work on other tasks.”
To create a prosthetic ear, Vest takes a mold of the patient’s unaffected ear and scans it using the MDX’s active piezo sensor, creating a digital file. The Roland Active Piezo Sensor (RAPS) transforms the machine into a 3D scanner for scanning 3D objects and creating 3D data. It scans data with hair-splitting precision, picking up minute shape variations. Minimum scanning pitches are: X/Y-axis direction 0.002 to 0.197 in. settable in steps of 0.002 in., Z-axis direction 0.001 in.
The digital file is then mirror-imaged through the machine’s software, MODELA CAM. This software accepts IGES, DXF and STL files exported from the popular industrial 3D CAD software programs. It can generate proportional 3D scaling, identify milling direction and automatically generate and display the tool path. The CAM software allows you to design in a variety of popular 3D CAD and computer graphics software programs, including SolidWorks, Rhinoceros, VectorWorks, LightWave and 3D studio max. It is also compatible with Windows® 95/98/ME/2000/NT4.0/XP.
Once the mirror image is done, Vest installs the MDX’s milling spindle and sets the machine to mill a wax cast of the prosthetic ear. “I use the 0.2 millimeter setting, which provides precise skin texture details,” said Vest.
Vest then uses the milled wax cast to fabricate a prosthetic ear. She hand-sculpts the prosthetic to accommodate the patient’s existing anatomy and any attachment mechanism, and colors it to precisely match the patient’s skin tones. “Before, I would heat a pot of wax and carve the ear by hand,” said Vest. “The MDX creates a mirror image of the patient’s existing ear with extreme accuracy, and allows me to focus on fitting and finishing the prosthesis.”
“I got into this field to make meaningful art that helps people improve the quality of their lives,” said Vest. “The MDX scanning/milling machine helps me provide precise aesthetic restoration so our patients are comfortable in any situation.”
Subtractive Rapid Prototyping (SRP), which is starting with a solid object and removing unwanted material, can have several advantages over traditional rapid prototyping. One advantage can be cost, it can be less expensive with the same resolution than using traditional rapid equipment. SRP machines typically mill a wide range of materials that cost less as well, and there is no need for chemicals or post finishing work. Plus, they produce a superior finish.
Roland DGA Corp.