Pioneering research validates new dental 3D-printing materials

As part of the nationally funded 3DCer4Dent project, researchers are currently testing new materials for 3D-printing dental implants. Carried out at the University of Turin, Polytechnic University of Turin, University of Catania and University of Perugia, this research and development is focused on evaluating the mechanical properties and behaviour of prototypes 3D-printed from ceramic—a tougher, more durable material than the polymers used for provisional restorations.

The metrology division of the University of Perugia’s Smart Manufacturing Laboratory is playing an important role in this research. In addition to developing artificial intelligence and advanced robotics, its team is increasingly turning to submillimetre-accuracy optical measurement to support their analyses. Using the Artec Micro II desktop 3D scanner (Artec 3D), the researchers test for geometric variations in different 3D-printed samples provided by a dental partner. This process is largely about guaranteeing an optimal marginal fit and optimising 3D-printing settings to compensate for material shrinkage—which can be an issue with existing resins. If there is a gap between a 3D-printed crown and the implant abutment, patients are likely to develop infections that lead to implant failure. However, by harnessing the versatility of 3D printing, it is thought that both the shape and the material properties of these restorations can be optimised by fine tuning the printing parameters.

In the past, researchers were restricted to inspection with radiographs and optical tomography. Now, implants can be loaded on to the Micro II, which rotates each sample on a built-in platform while patterned light is projected on to the implant surface from all angles. Within minutes, it is possible to analyse the morphological characteristics of the implant and assess whether it meets design and manufacturing specifications.

Currently, in this workflow, the team processes and analyses data in Artec Studio, a software program that fuses scans into a 3D model for comparison with the original CAD using built-in tools such as distance mapping and thickness analysis. For more advanced analyses, such as the comparison of complex curved surfaces, programs like CloudCompare (Daniel Girardeau-Montaut) and MATLAB (MathWorks) are also used.

Early results have uncovered significant deviations in geometric accuracy between two silica-based ceramic materials. One material clearly outperformed the other, demonstrating the practical value of the researchers’ methodology.