Impact of Layer Thickness and Storage Time on the Properties of 3D-Printed Dental Dies

The purpose of this study was to evaluate the effect of printing layer thickness on the repeatability and surface roughness of 3D-printed dies and detect the effect of layer thickness and storage time on the dimensional stability of 3D-printed dies. One stereolithography (STL) file of an upper molar prepared for a full ceramic crown was used to print three groups of dies: 25 µm, 50 µm, and 100 µm. Repeatability was evaluated by linear and area measurements with a digital caliper and a digital metrology microscope. Dimensional stability was analyzed at 3 weeks, 6 months, and 1 year of storage time. Surface roughness parameters were measured with a 3D confocal laser scanning microscope. Statistics were completed using one-way analysis of variance and Tukey's post hoc tests, p < 0.05. Printing time decreased as layer thickness increased. All groups showed high repeatability and comparable surface roughness while showing differences in their linear dimensions and surface areas. At the 3 week storage interval, dimensional changes were observed in all groups. Within this experimental study's constraints, it can be concluded that changing the 3D-printing layer thickness does not affect the repeatability or the surface roughness of the product; meanwhile, changes to the layer thickness and storage time influence the dimensional stability of 3D-printed dies.