Evolving Chemistries, Expanding Applications
Developments leading to increasing adoption
Stephanie Benight, PhD
The past decade has brought significant advances in 3D printable polymer materials, which has elevated polymer-based materials to dominance in the dental 3D printing industry. Previous acrylic-based materials were brittle and very sensitive to water uptake, limiting them to prototyping applications. Recently, hybrid materials have been and continue to be developed that utilize multiple types of chemistry to create strong mechanical properties, good physical properties, biocompatibility, and in some cases resilience to high heat.
What are the latest developments in 3D printing
Models and surgical guides have been the focus for several years, but there are few good options on the market for each, despite laboratories being familiar with these materials and routinely printing with them. I am excited about the new denture materials coming to the market because we are achieving new levels of quality for flexural modulus, flexural strength, low water uptake percentages, and esthetics. The next frontier is direct substitution of teeth, whether in dentures, implant overdentures, aligners, or other appliances, with materials that have the required properties as well as the low cost requirements necessary to make them effective and adoptable for dental laboratories.
What are the most important considerations when purchasing materials?
When you pivot from a millable technology to a 3D printable technology, you need to ensure the advertised properties are accurately represented. One of the most important factors is following the workflow instructions provided by the manufacturer. FDA approval is achieved via the manufacturer submitting specific workflows, including printer settings, post-processing protocols, etc. Even when all the proper steps are followed, one rampant issue in 3D printing is overinflation of the properties that a material can achieve. In my research across various verticals, not just dental, I have found that certain materials simply cannot achieve anywhere near the properties that are advertised. Verifying material performance with third parties is important. I encourage customers to review the specification sheets, and then follow the FDA-approved workflows to ensure they get the physical properties advertised by the manufacturer.
What needs to happen for 3D printing to be more useful and widely adopted in dentistry?
I am a big proponent of standardization in the testing of material properties. The industry is increasingly adhering to material testing standards, and I am involved with multiple organizations working toward that goal, including the new Photopolymer Additive Manufacturing Alliance (PAMA). Recyclability is another important factor as these materials move toward mass production and daily use. For example, there are materials that can be incorporated into the post-processing workflow that act as curing agents to solidify residual liquid resin. The resulting solid can simply be placed in the trash. This is a huge value add as laboratories move toward scaling workflows and mass production. Another issue is that many printers currently operate on a closed system, which stifles material innovation and limits the customer's choice of materials for their printer. An open material ecosystem would really catalyze the adoption of the technology.
I am incredibly bullish on 3D printing being used pervasively in the dental industry for a variety of appliances and applications. The potential for automation, mass production, and flexibility will help propel 3D printing and digital dentistry to the forefront of the industry.
About the Author
Stephanie Benight, PhD, is Project Director of 3D Printing for Myerson, LLC. She serves on ASTM Committee F42 on Additive Manufacturing Technologies and is a Special Advisor for the Photopolymer Additive Manufacturing Alliance (PAMA).