1. Align Technology (Nasdaq:ALGN): +131.1%
3D printing is a new thing for many medical device companies. Align Technology (San Jose, Calif.) has been a pioneer. For the first nine months of 2017, the company’s revenue was up a third, to more than $1 billion, and profit was up 55%, to more than $142 million. The company joined the S&P 500 Index in 2017, too. Fueling the growth is Align’s Invisalign teeth aligners, made of the company’s virtually invisible SmartTrack material and 3D printed to custom fit a person’s teeth based on precise 3D digital images. In November, the number of people treated with Invisalign reached 5 million. Align has also had success with its iTero teeth scanner, which captures 100,000 points of laser light in perfect focus without the industry-standard use of powder to coat the teeth.