Step back Katie and look at it from 1st Principles:
Basically what 3D printing is, is a reverse form of CNC milling, but also one that can do contained shapes.
but it is slower than CNC and more limited in materials
FDA has so far approved 85 medical devices made using 3-D printing, most of them via the 510(k) or emergency use pathways. It is predicted that most hospitals will purchase a least one 3-D printer for use in Operating Room service area in the next 3 years.