Using a Stratasys Dimension 1200es 3D printer from the New Jersey Institute of Technology, Amos Dudley, a digital design student, 3D Printed his own set of orthodontic aligners. Since it was a DIY aligner costing less than 60$ compared to 1K$, it went viral within a week.
Source: http://www.sciencealert.com/a-college-student-has-3d-printed-his-own-braces-for-less-than-60