Some 34 men out of 100 suffer from sleep apnea, and Dr. Christopher Hart was one of them. The condition blocks the airways and causes people to temporarily stop breathing. It also can jolt them awake several times during the night. The most common treatment involves a method called Continuous Positive Airways Pressure or CPAP, which requires sleeping with a bedside pump that forces air through a mask worn over the mouth and nose. But the treatment is so uncomfortable that in one study, almost half of the patients gave up on CPAP even though it’s shown to help in the long term.
Hart, a dentist in Australia, hated using CPAP. “You just can’t get to sleep with it on,” he says. He knew enough about the anatomy of the mouth that he thought he could build an effective alternative. For his first attempt in 2012, he used a bendy straw that snaked along his gums and then around the back of his teeth toward his throat. It wasn’t something he could sleep with, but the straw sent air directly where it needed to be.
For his next attempt, Hart took a small vacuum pipe that dentists use to clear saliva and bent it along a similar path. He then used dental mold material to create a customized mouth guard that included the pipe. It was crude, but it worked.
So he asked his business partner Michael Slater to create a one-piece prototype out of molded plastic. Slater, who used to work as a dental lab technician, spent six weeks developing a bulky prototype that took 18 hours to make by hand.
Medical device company Oventus makes a sleep apnea device that’s part 3D-printed titanium, part soft polymer. The goal was to create a more comfortable alternative to CPAP masks. Above: 3D printing allows Oventus to customize the devices to each patient, using a scan of the patient’s mouth and customized design software. Images credit: Oventus
Hart and Slater, who later founded the medical device company Oventus, knew they needed to do better. They brought the prototype to Neil Anderson, a biomaterial scientist, who suggested they make it on a 3D printer.
Anderson, who now serves as CEO of Oventus, sent Hart and Slater to CSIRO, Australia’s federal government agency for scientific and industrial research. For the past three years, CSIRO’s Lab22 in Melbourne has been working with 3D printers that can make parts from a bed of powder, layer by layer. A couple of the machines were made by Arcam AB, the Swedish maker of 3D printers and metal powders in which GE acquired a majority stake last fall.
At CSIRO, the team experimented with several materials and settled on titanium. The metal “was an obvious choice of material for Hart’s oral device,” says Stefan Gulizia, who runs 3D printing research at CSIRO. “It’s strong and biocompatible, meaning it doesn’t corrode in the body, and is unlikely to cause tissue reaction.”
Gulizia said that the Arcam machines were the perfect fit because they preheat the titanium powder in a vacuum to prevent residual stresses after the printing. The combination of heat and vacuum gave Hart and Slater more control over the structure of the device.
The first device, dubbed the O2Vent, was ready 11 months after Hart’s team began its discussions with CSIRO. The device is a 3D-printed titanium mouthpiece with an airway opening that protrudes from the lips and an air channel, nestled in a soft, medical-grade, polymer inner, customized to the patient’s teeth.
3D printing has other benefits. Because 3D printers do not require molds and other expensive tooling, the technique allows Oventus to customize O2Vents to each patient, using a scan of the patient’s mouth and customized design software.
“The first night I slept with the O2Vent was the best night’s sleep I’ve ever had,” says Hart. “My wife kept poking me to make sure I was alive because she couldn’t hear me breathing.”
Recent studies bear out Hart’s enthusiasm. The average compliance time for CPAP is 3.5 hours a night; for O2Vent it’s 6.1 hours a night, and one study showed that 76 percent of patients using the O2Vent decreased their Apnea-Hypopnea Index (AHI), or number of obstructed breathing events, by more than 50 percent, with another study showing a 78 percent reduction in the number of events.
Hart is sleeping better not just because his sleep apnea is now under control but also because he sees how his device is helping so many people.
The responses from patients are just phenomenal,” says Hart. “It’s very hard to get the devices off people just to make an adjustment! They want to wear it. They feel better. They’re not snoring. They’re getting better sleep. And they have more energy.”