Reimbursement is not based on the technology used but the medical value of the product or service derived from it. So 3D printing is no different from any other technology other than is is newer, so presumably less proven although seen to have many potential benefits. So the question is not really about 3D printing more about how it might improve medical products and who is willing to pay for this value add and what proof is required to show this perceived value. . To me the opportunities for 3D printing of medical devices are around the ability to mass customise which is great for implants etc where a more personalised prooduct can bring benefits and potential the ability to improve durability of devices. The challenges are then whether payers will pay for the additional benefit - that probably requires clinical research to show the value.
regulation is another issue - will regulators see risks in new processes based on 3D printing and hence not approve products in which case reimbursement won’t happen.

I had an answer in my mind, but found out later that Mr. Simpson has already provided a clear answer that I concur with. So let me put it very briefly.
Provided 3D Printing offers a product that is a little bit better at a lower cost, or very much better, then it would be approvable and would be reimbursed. If it is not better or cheaper or both, why should anyone be interested?
(Whether it is “better”, one should consider the product’s efficacy / effectiveness, and possibly its convenience, or whether it solves an important issue not addressed by other, alternative products / approaches.)

You need to consider the specific application of 3D printing. As noted above, one of the applications of 3D printing is implantable devices. Additionally, there are applications in medical education and surgical planning. In the case of surgical planning, there might be potential for reimbursement under existing CPT codes for surgical planning.

I believe that reimbursement for 3D printed models is happening in a number of countries in Asia with (I think) Japan leading the way. Such models are being used for diagnostic and planning purposes. Invisalign uses 3D printing as part of the manufacturing process for dental aligners, which is reimbursable. I recall that a few US insurers are now reimbursing for 3D printed parts but not sure of the specifics and can't find the related article.