Evaluating Accuracy, Precision, and Speed: Stephan Kreimer Puts New Model Resins to the Test

Stephan Kreimer is a Master Dental Technician and director of Kreimer Dentallabor GmbH & Co. KG. Kreimer's lab is hugely productive — the team 3D prints an average of 300 dental models each month, about 60% of which are highly precise restorative models. To continue their high standard of care, Kreimer is always evaluating new technologies  and materials in the dental 3D printing space. He tested out two new Formlabs model resins, Precision Model Resin and Fast Model Resin, putting them through a thorough evaluation process.

Formlabs took advantage of the advanced hardware of the Form 4B 3D printer to develop two new, industry-leading materials for dental applications. Kreimer put both to a rigorous test, printing models to scan and check for accuracy and precision. While he was first impressed by Precision Model Resin, capable of printing restorative models with over 99% of printed surface area within 100 μm of the digital model, he found that Fast Model Resin “has advantages for certain indications due to its speed, smooth workflow, and lower cost.” Ultimately, he sees the most benefit in working with both materials, selecting a resin based on the application to achieve maximum efficiency and optimal results.

Resins for restorative models must be highly precise and accurate. Kreimer says, “For all restorative models, such as crowns, bridges, and implant cases where precision is crucial, you need a material that is highly precise and accurate. For example, when printing implant models with implant analogs or models with removable dies, the fit must be perfect without any adaptation.”

Additionally, Kreimer says, “The model resin should be visually comfortable. Opacity is preferable to translucency for this type of model, as it is easier on the eyes during extended periods of work and makes it easier to see margins and small details.” Precision Model Resin has matte aesthetics and a gypsum-like appearance to better distinguish margin lines and fine details. 

Kreimer thoroughly tested Precision Model Resin, starting with test blocks to evaluate the printing of fine details and to assess geometric accuracy. Additionally, he prints test models and analyzes the printed and post-processed models against the original STL dataset. Finally, he creates test bodies for implant analogs to examine the fit and reproducibility.

With these tests showing good results, Kreimer moved on to his usual material evaluation, printing and post-processing typical patient cases which he then scans with a highly precise dental desktop scanner. He then uses software like GOM Inspect, to compare datasets. Kreimer says, “I perform these tests on at least 10 models to evaluate how the material behaves with different geometries. This test is crucial to ensure I can trust the workflow for our patient cases." Kreimer looks for models that are as close as possible to the STL file. The closer the print is to the original model, the more accurate the fit of the final appliance is for the patient.

Internal testing at Formlabs shows that parts printed with Precision Model Resin have 99% of the surface within 100 μm of the CAD model and 95% of the surface within 50 μm of the CAD model when printed at 50 μm layer heights.

The majority of the dentists Kreimer works with follow a digital workflow. Kreimer states, “85% of our customers send us intraoral scans instead of physical impressions. Our dentists appreciate working with us not only for our expertise in digital technology but also because it saves them a lot of chairside time."

Kreimer provides an example of a telescopic crown case. In a conventional dental lab using traditional methods, it's common for the patient to have four to five sessions with the dentist for impressions, bite registrations, a try-in, and a final insertion.

With an intraoral scan, Kreimer obtains more precise information than with a physical impression alone. Additionally, Kreimer notes, “The 3D printing materials, like Precision Model Resin, have become much more precise and accurate than the materials we used before. We can now complete about 80% of even the very large cases, like full arch cases, with one scan and two to three sessions. This helps save sessions for both the patients and the dentist. As a lab, we benefit from fewer intermediate steps, allowing us more time between sessions to focus on aesthetics."

With intraoral scans, fully digital workflows, and highly precise printing materials, it’s possible to produce an accurate appliance that fits the first time, cutting out appointments and saving valuable time for dentists, patients, and the lab.

Kreimer Dentallabor, like most dental labs, prints models for various applications. At first, Kreimer says, "I thought Precision Model Resin would be my only dental model material, but when I saw the printing speed and surface quality of Fast Model Resin, I was impressed. It still looks quite good for a dental model. I love using it for applications like splint models, aligner models, or provisionals — any models that don't require 100% precision and where speed is important."

On Form 4B, it’s possible to print 10 restorative models in Precision Model Resin at 50 μm in one hour and 50 minutes. With Fast Model Resin at 160 μm, 11 models can be printed in just nine minutes. For models where precision is not the most important feature, printing Fast Model Resin at a thicker layer height therefore saves significant time on what is already a fast print job. As Kreimer says, "My workflow would be much less efficient if I only used Precision Model Resin because Fast Model Resin allows me to produce a higher volume of cases each day. For cases requiring high precision, I can still rely on Precision Model Resin."

Selecting a resin based on the requirements of a particular application enables true optimization and efficiency. Kreimer also says, "You don't need a lot of materials as long as you have the two that meet your specific needs." In this case, Precision Model Resin for precise, accurate models, and Fast Model Resin for models that require slightly less precision and blazing fast print speeds. 

Precision Model Resin and Fast Model Resin were formulated to leverage the new Form 4B ecosystem for faster print speeds, more accuracy, and enhanced aesthetics. Kreimer says, "I've been waiting for years for Formlabs to update its technology to cure the entire build platform simultaneously, and now it's finally here. It's truly a game changer for our daily workflow!"

The speed of Form 4B makes the same intuitive workflows faster than ever, meaning everything from onboarding to learning new workflows to daily printing is more efficient.

Form 4B is a masked stereolithography (MSLA) 3D printer, enabling faster print times than previous generations. Additional updates to the Form Wash increases the speed and effectiveness of the entire workflow. Kreimer says, "I also love the improved washing capabilities of Form Wash. It has significantly more power, making it easier to clean parts. Additionally, since the materials are cured to a higher level with Form 4B, cleaning is even simpler. The entire post-processing workflow is better and faster now."

The advanced hardware of Form 4B combined with new materials enable dental professionals to print models and appliances at faster speeds with more efficient workflows — and all with more precise results.

Good dental technicians can be hard to find and their labor is expensive, but leveraging the optimal tools and materials quickly pays off. Form 4B is fast and accurate, with intuitive workflows for efficiently produced appliances that fit, enabling labs to grow production without increasing demands on staff or overhead costs. 

Start printing with Precision Model Resin and Fast Model Resin now, or contact a dental expert to learn more about bulk resin discounts when purchasing 30+ liters of resin.