Additive manufacturing -- a.k.a. 3-D printing -- has moved beyond being a primarily techie and Wall Street topic to capture the attention of many on Main Street. This attention is well deserved, given the 3-D printing sector is expected to balloon from $2.2 billion in 2012 to nearly $6 billion in 2017, and will eventually touch, even transform, many diverse facets of our economy and lives.

While the health-care sector is in the relatively early stages of adopting 3-D printing, it's already obvious that 3-D printing will revolutionize health care. We're going to explore a sampling of the life-improving advances in medical technology already made possible by 3-D printing, as well as the mind-boggling ones that loom on the horizon. Companies discussed are 3-D printer makers 3D Systems Corporation (DDD 2.36%) and Arcam AB (NASDAQOTH: AMAVF) and tissue engineering -- or "bioprinting" -- company Organovo (ONVO 9.82%).

3-D Printing 101
First, a quick summary of 3-D printing. 3-D printing involves using digital 3-D design data to build up a component layer by layer. By contrast, traditional manufacturing is subtractive by nature, in that it involves whittling away at a chunk of material to form the desired part. It's only been recently that 3-D printing has expanded beyond prototyping and into production applications. This is because there have been tremendous recent advances in 3-D printing technology and in materials availability.

3-D printing can save time and money, as the technology uses less raw material than conventional manufacturing, and eliminates the need for tooling since the process involves going directly from design to production. More importantly, however, is that 3-D printing unleashes innovative possibilities because it allows for designing and producing some components that can't be made using traditional production processes. This factor is at the heart of 3-D printing's ability to revolutionize health care.

Personalized medicine
The sequencing of the human genome has made personalized medicine a hot topic recently. It's often overlooked that, like genetic sequencing, 3-D printing can also be a technology that's used in personalized medicine. This is because 3-D printing allows for products to be custom made to fit individuals, which is of critical importance when we're talking about medical devices, such as orthopedic implants, dental implants, and the like. Conventional manufacturing techniques can't always produce such exact-fitting devices.

Let's start with a heartwarming example that underscores this key strength of 3-D printing.

3D System Corp., which is the largest (by market cap) maker of 3-D printers, is well acquainted with the health-care sector, as it accounted for 20% of the company's product revenue in 2013.

However, just last month, 3D Systems announced a first on the health-care front: the first 3-D printed hybrid robotic exoskeleton suit, which it teamed with Ekso Bionics to produce. The suit was made for Amanda Boxtel, whose skiing accident in 1992 left her paralyzed from the waist down. She was able to stand and walk, assisted with crutches, during a public event in which she debuted the suit. "After years of dreaming about it, I am deeply grateful and thrilled to be making history by walking tall in the first ever 3-D printed Ekso-Suit, made specifically for me," she said.

Source: 3D Systems Corp.

3D Systems' designers scanned Amanda's thighs, shins, and spine so the suit would be custom fit for her. A 3-D printer then produced the Ekso suit from the scans. Mechanical actuators and controls, which Ekso Bionics manufactured, were then integrated with the 3-D-printed portion of the suit.

Pioneering 3-D-printed orthopedic implants
Sweden-based Arcam is a pioneer in making 3-D printers that can produce both standard and custom-made orthopedic implants. Implants using Arcam's proprietary electron beam melting, or EBM, technology were CE marked in 2007 (CE is the European equivalent of the FDA), and implant manufacturers using EBM received FDA approval in 2011 for select products.

There's little doubt that an increasing proportion of orthopedic implants will be produced using 3-D printing. That's because, in some instances, 3-D printing can reduce the cost of producing implants, improve their quality, and better customize them.  

A good example relates to implants with trabecular structures, which are the porous type of bone found at the end of the spine and at all articulating joints. This porous section promotes bone integration, as it has an increased surface area, which new bone attaches to. 3-D printing can produce the solid and porous portions of the implant in one step, whereas traditional manufacturing involves two steps: the machining of the solid portion, followed by the application of a plasma spay for the porous section. So, there's the obvious time and cost savings here. More critically, from the patient's standpoint, is the considerable improvement in quality. Over time, the porous section produced by the traditional two-step process can debond, which means the implant won't last as long in the patient. 

Bioprinting human livers and other organs
Organovo's involved in 3-D printing cells to produce human tissues with the ultimate goal of producing organs that can be used in transplants. It's a developmental stage company that made a splash late last year when it announced it bioprinted 3-D liver assays that were able to retain key liver functions for more than 40 days. The company plans to market its liver assays, which will be its first commercially available products, at the end of this year.

There's huge promise in focusing on the liver because liver toxicity is a primary reason why drugs that have made it through preclinical testing fail in clinical trials. Drug companies could prevent much wasted time and save billions of dollars if liver toxicity issues were detected earlier in the drug development process. Organovo's liver assays hold much potential as a drug-testing tool, among other uses.

Organovo's top execs and other industry experts have stated that we're at least a decade, perhaps two, away from being able to print solid organs, such as the liver, heart, and kidney. This achievement, of course, will be an ultimate gift from the gods for the many people around the world who suffer and die each year because of organ failure while they await a transplant.

Bioprinting solid organs won't remain in the science fiction realm, as some skeptics believe. There has already been considerable progress in bioprinting. Several entities -- most notably, Wake Forest Institute of Regenerative Medicine -- have used bioprinting to produce tissues and select (flat and non-solid) organs used for transplants. 

Foolish final thoughts
3-D printing is well on its way to revolutionizing health care, which should improve the quality of life for multitudes of people, and enrich investors in those companies that most successfully provide 3-D printers to the health-care sector and those health-care companies that most successfully employ this technology.