Supriyadi

The fact of the matter is that not all resins are suitable for even basic study models. But although dental model resins are some of the most widely marketed materials in dentistry, models represent only a fraction of 3D printing’s capability in digital dentistry. Functional, final-placement appliances are growing in number, and these FDA-cleared, biocompatible resins are the future of the industry.

Dental Resin Type 1: Dental Model Resin

At first blush, one might mistakenly think that the requirements of a dental model are the same as any other 3D-printed part. But where they diverge, and where we find the point of divergence of most dental prints from other 3D-printed models, is in their intended use. While a 3D model of a character to be used for animation will be heavily post-processed and painted by an artist, a full-arch model of a patient’s teeth needs to be useful with minimal effort. This cashes out in two ways.

CONSULTATIVE AND VISUAL DENTAL MODELS

Dental model resins need to properly balance speed against aesthetics. Doctors like Steven Shao use 3D printed dental models as visual aids for restorative treatment consultations. In order for these consultations to be effective, the models need to be visually appealing. Proper color distribution, especially over the course of long prints, is something that many standard model resins do not prioritize. Dr. Shao uses SprintRay Model Resins, which are specifically formulated to print rapidly while retaining even color and micron-level accuracy.

DENTAL MODELS FOR CLEAR ALIGNER PRODUCTION

Another popular use for 3D printers, particularly in private practices, is the creation of in-house clear aligners. This process involves printing a handful of full-arch models that progress from a patient’s current to future dentition. Clear aligner therapy production brings up the most important component of dental model resin: accurate throughput.

Many desktop SLA printers use a single laser to cure resin as if drawing a picture one layer at a time. Desktop DLP printers like MoonRay cure an entire layer in a single flash of UV light. This makes them very accurate and fast, two items that are critical in the production of clear aligners. Because clear aligner therapy requires the printing of up to a dozen full arch models, throughput is crucial. Rather than having to print each arch on its own print bed or wait for each layer to be individually drawn, DLP printers can get the best of both worlds.

But speedy, accurate production isn’t just about printer tech. Speed and accuracy are adversely affected by materials. Dental materials are engineered for this balance. If the accuracy of the full-arch models isn’t spot-on, then the aligners themselves won’t fit properly. High throughput with reliable accuracy is the result of years of tweaking model resins specifically for the needs of dental professionals.

Dental Resin Type 2: Functional Appliance Resin

The last couple of years have seen a handful of breakthrough resins that are certified by the FDA as Class Ia and IIa biocompatible. These new resins also have physical attributes that make them ideal for dental applications. Hard, clear plastic mouthguards and nightguards can be printed on certain compatible 3D printers. Indirect bonding trays, which are loaded with orthodontic brackets and then seated for simplified bonding, can be printed in less than an hour. Denture try-ins and monolithic, economical dentures can be printed with PMMA micro-filled hybrid material, post-processed, and placed into a patient’s mouth within a day and for a fraction of the materials cost.

You might be thinking: great! If there are so many new functional resins on the market, why aren’t all digital dentists using them? Unfortunately, things aren’t so simple. Most systems are still “closed” which means it can be difficult to find the combination of product features and material compatibility that will work for your practice.. In order for a given printer to print with a certified denture base resin, for example,  that printer must have the correct software presets. If it doesn’t, the print will fail.

Open vs. Closed Resin Systems

Just as with paper printers, the wide profit margins of consumable supplies drive company decisions around materials. Many dental 3D printing materials are made by third-party resin suppliers. Only a very small handful of 3D printers allow for third-party resins. Even fewer offer support and offer pre-made settings to ensure compatibility. Most 3D printers, even those built for dental, use proprietary ecosystems. If you invest in such a printer, you may limit your ability to see future returns on your hardware.

Certified Open Resin Systems

3D printers for dental clinics and labs should be long-term investments. While hardware iterations are on fairly long product cycles, dental 3D printing materials are not. Resin manufacturers move fast, and clinics need a partner who can help them stay up to date. Many of the functional resins on the market today have become available within the last year, and that rate of improvement shows no signs of slowing down. The success of 3D printing in dental owes much of its capability to these new resins developed by third parties.