By Alyx Arnett
Manufacturers are increasingly turning to medical-grade nylon polyamide 12 as the material of choice for oral appliance therapy for sleep apnea. The recent influx of nylon options, made possible by 3D printing, is attributed to several factors, including technological advances and market acceptance.
Panthera Dental was one of the first companies to enter this space (following ResMed, which released the Narval CC in 2012 but discontinued it in the United States in 2018), launching its first nylon appliance in the United States in 2014. Several others have since followed suit. “The industry is realizing it’s an amazing material that allows for speed, precision, and multiple appliance design options that older technologies do not allow,” says Marc Morisset, vice president of Panthera Dental’s sleep division.
Open Airway Dental Solutions, which acquired Australia-based oral appliance maker Oventus Medical last year, has been fabricating nylon oral appliances exclusively since 2019. “The whole process has shifted into what we call the ‘new world,’ rather than the old-world acrylic,” says Sat Sharma, MD, FRCPC, FCCP, FACP, FAASM, chief medical officer at Open Airway Dental Solutions.
Other manufacturers—including BFit Sleep, Great Lakes Dental Technologies, Slide2Sleep, and OrthoApnea—have introduced nylon versions of acrylic-based devices, while others, like Australia-based Good Sleep Co, entered the oral appliance market exclusively with nylon.
BFit Sleep’s Chris Gillette, RPSGT, attributes the influx to advances in technology. “The reason people didn’t do them earlier is because the technology wasn’t quite there yet, and they were so expensive to make that it wasn’t a margin that you could afford to do as a company,” says Gillette, the company’s owner.
BFit Sleep, which had experience in 3D printing acrylic resin-based appliances, released its nylon oral appliance, the BFit Sleep Nylon MRC, in 2023. The launch has been so successful, says Gillette, that BFit Sleep is discontinuing its acrylic resin-based 3D-printed oral appliances.
Tyler Sisson, director of strategic business partnerships and technology development at Great Lakes Dental Technologies, which manufactures a nylon oral appliance in-house, the Nylon Sleep Herbst, and also distributes other brands’ nylon products, attributes the rise to market acceptance and viability. “The legwork that some of those companies did early on really has started to show itself, with the appliances gaining traction and nylon becoming widely accepted as a viable material,” Sisson says.
Benefits of Nylon
Manufacturers of nylon oral appliances highlight several advantages of the material, including strength, versatility, comfort, and accelerated production.
Strength
Before shifting to nylon, BFit Sleep had transitioned from lab-made, standard acrylic devices to 3D-printed acrylic resin-based appliances. However, according to Gillette, the company received broken devices every few months, usually due to teeth grinding from heavy bruxers.
Having to remake so many acrylic appliances led to the switch to nylon last year. Gillette reports that the company hasn’t yet had any nylon appliances returned for repair.
Miguel Barrio Rosales, head of engineering at Spain-based oral appliance maker OrthoApnea, points out that, compared to biocompatible resins, the mechanical properties of nylon polyamide 12 are much better for 3D printing. “Some printed resins tend to be very rigid and brittle, while others that try to mimic nylon end up being too soft and wear out very quickly,” he says.
Slide2Sleep’s entrance into nylon stemmed from challenges with the rails on its acrylic Slide oral appliance. Though the rails were made of “super strong” polycarbonate that went through US Food and Drug Administration testing for strength, over time they eventually cracked under the dynamic stress caused by bruxing, says Kelly LeBlanc, DDS, DABDSM, DASBA, the Houston-based company’s founder and CEO.
Slide2Sleep began exploring alternative materials and released a nylon version of the Slide in June 2023. The company also switched to nylon rails on the acrylic device. “You can run over it with a truck. It won’t break the rails,” LeBlanc says. “We haven’t had any failures since we’ve switched over to the nylon versions.”
Versatility and Comfort
Nylon’s durability allows for versatility. It can be 3D printed thickly—over 2 millimeters—and become extremely rigid, or extremely thin and be extremely flexible.
“That’s a very strong point when we’re creating an appliance in the mouth and when we want to diffuse or redistribute forces that are applied to the teeth and the joints. We need rigidity at some spots, and we need flexibility at others,” says Morisset.
Coupled with 3D printing technology—known as additive manufacturing (as opposed to subtractive manufacturing that’s used in milling)—nylon oral appliances can take on any shape.
“So if we take all of these things together, we can basically create an appliance that fits like a glove in the mouth of the patient,” says Morisset.
Joel Simpson, co-founder of Good Sleep Co, says these properties were what the company sought when it began exploring the addition of an oral appliance to its suite of dental sleep retail and software products. “We knew that the smaller they were, the better the patients did. The more comfortable, the better efficacy. With nylon, we were able to make it very, very small,” says Simpson.
Accelerated Production
Nylon 3D printing allows for rapid prototyping and faster production cycles compared to the traditional handcrafting process used for acrylic devices.
Speed was a key consideration for Open Airway Dental Solutions. In 2019, the company dropped its previous acrylic and titanium combination in favor of quicker and more precise 3D printing with nylon.
“[The previous appliances] were handmade and took a really long time. Just to create one appliance would be half a day’s worth of work,” says Sharma. “So our company evolved, more studies were done, and the whole shift was to choose nylon as the material.”
According to Morisset, this process allows Panthera Dental to deliver appliances in eight days once the patient material is received. “We want patients to be treated as quickly as possible, as time to treatment is important for any healthcare professional,” says Morisset.
Downsides to Nylon
Nylon oral appliances also have potential drawbacks, including challenges with chairside adjustments, retention issues, and higher costs.
Difficult to Adjust Chairside
Acrylic devices can be easily adjusted or repaired chairside by any dentist with the necessary equipment. This isn’t the case with nylon. If material needs to be added, a new device must be made, according to Morisset.
However, Morisset says this downside is mitigated by 3D printing technology, which ensures a high rate of good first-time fits.
This means patients needing future dental work may be better off with an acrylic device, which can be easily relined and refitted, says Slide2Sleep’s LeBlanc.
Some companies also offer replacement policies and warranties to account for nylon device remakes. For example, Panthera Dental and Good Sleep Co account for potential mishaps—like a patient getting a tooth knocked out or requiring unexpected mouth surgery or dental work—by offering free remakes within the first 60 days in the United States.
Retention Challenges
Retention is somewhat of an issue with nylon appliances, Sharma explains. Patients with short dental arches (short counts) may not be ideal candidates for nylon appliances due to the limited dimensions.
However, Sharma says Open Airway Dental Solutions’ nylon devices—the O2Vent Optima, O2Vent Optima Mini, and O2Vent Connect—may offer better retention because they are fitted over the gum tissue.
Because Panthera Dental’s devices use undercut retention, edentulous patients aren’t good candidates for its oral appliances. (Patients need at least four teeth per quadrant.)
Additionally, patients with sharp teeth may not be great candidates due to a lack of retention, Sission adds.
Still, “probably for 90% of people, nylon works very well for them,” says LeBlanc.
Cost
While the costs of nylon oral appliances have decreased in recent years, some manufacturers say they remain more expensive than acrylic-based devices.
“In general, nylon appliances tend to be positioned as a premium product that requires a more sophisticated design process,” says Sisson.
Nylon polyamide 12 is more expensive than other materials, and the 3D printing process necessitates significant investment from manufacturers that print in-house. “A lot of the nylon manufacturing requires machinery that is larger than, for instance, a desktop 3D printer. It’s industrial machinery. So there’s an investment that goes into getting up and running,” says Sisson.
Sisson adds that the design process incurs the most cost. The appliances must be designed using advanced software, which can involve significant labor costs for the technicians.
Helping to offset patient costs, some nylon appliances have received Pricing, Data Analysis, and Coding approval. For instance, the Panthera D-SAD Classic and Nylon Sleep Herbst can be billed for Medicare beneficiaries using the Healthcare Common Procedure Coding System (HCPCS) code E0486. Others, including the Panthera D-SAD X3, O2Vent Optima, O2Vent Optima Mini, and the Slide, can be billed under HCPCS code K1027.
The Future of Nylon
Many manufacturers believe the industry will continue to trend toward nylon for oral appliances. “I think it’s the future,” says Gillette.
Sharma from Open Airway Dental Solutions anticipates the nylon oral appliance process will become even more streamlined and cost-effective. For example, his company uses vapor fusion technology, which results in a smoother and more refined surface finish.
Looking ahead, Sission would like to see smaller nylon-centering machines that are appropriate for medical device applications. “It would be very interesting to see the smaller users having access to nylon manufacturing in-house,” he says.
Panthera Dental’s Morisset adds, “The combination of 3D printing and medical-grade nylon in manufacturing oral appliances already benefits both providers and patients. Leveraging this technology with custom CAD/CAM sleep device software will further enhance precision, comfort, and design versatility, and promises a bright future for nylon appliances.”
Simpson has a more cautious view. He points out that nylon is expensive to set up and start manufacturing. “To say that nylon long-term is the future, I don’t know. Certainly, for the next five years, it’s going to be the material of choice for its strength and comfort and all the rest of it,” he says.
Simpson emphasizes the importance of being adaptable and open to new materials and technologies as they develop. He suggests that, as printing technology and material science advance, new developments could potentially surpass nylon.
Photo caption: Polyamide powder, used in 3D printing, is shown alongside a lower splint from the final product, illustrating both the raw material and its application in the manufacturing process.
Photo credit: OrthoApnea
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