Influence of printing and post-treatment parameters on the mechanical properties of a dental resin

Stereolithography (SLA) is an additive manufacturing technique that uses photopolymerization to cure resins, creating solid parts layer by layer from a CAD design. In the manufacture of clear dental aligners, the use of this technique is increasing. This technique is used to create resin molds, which are then used to obtain customized aligners through a thermoforming process. SLA offers significant advantages in terms of precision, customization, and reduced manufacturing time and cost compared to other conventional technologies.

In this study, different printing parameters (layer thickness and orientation) and post-curing parameters (temperature and curing time) were tested to evaluate their effect on the mechanical properties.

A fractional Taguchi design was first used to identify the most influential parameters, leading to the development of the first specimens. By analyzing the results obtained for these specimens in impact using compression and tensile tests, complemented by thermal characterization and roughness tests, the most impactful fabrication parameters on the mechanical properties of the resin were determined.

Once these parameters were determined, a full factorial design was performed to analyze the effect of each variable and their interactions on the properties of the final product in a more comprehensive statistical manner.

Once the results were obtained and the process were optimized, a time reduction was achieved, which improved the aligner manufacturing process without affecting the mechanical and surface properties of the resin dental molds.