Surface Properties of Titanium Crown Fabricated by EBM

Objectives: The electron beam melting (EBM) process, which has a greater fabricating speed than selective laser melting (SLM), is used for manufacturing titanium models in the medical field, but no report in dentistry. This study aimed to investigate the surface properties of the crowns fabricated by EBM and to apply EBM to dentistry by comparing it with SLM, which is used in dentistry.
Methods: 3D data of a simplified crown with an outer diameter of 13 mm, an inner diameter of 10 mm, and a depth of 10 mm with a taper of 1/10 was created. The crowns were fabricated using EBM (Arcam A2X) and SLM (Concept Laser M2), with suitable titanium powder for each device. When fabricating the crowns, the data was set with the angle to the building platform at 0, 45, and 90 degrees, respectively. Post-processing was carried out following each manufacturer’s instructions. The surface roughness Sa (μm) and Vickers hardness were measured using an optical profilometer (VR-6000) and a hardness tester (AK-15), respectively. The number of repetitions was set to five. ANOVA and Tukey’s test of multiple comparisons were performed.
Results: The surface roughness of EBM was significantly larger than SLM in all angles, and the largest value was found in 0-, the smallest in 90-degree (p<0.05). In the SLM, there was no significant difference between 0- and 45-degree (p>0.05), and 90-degree showed the largest surface roughness than others (p<0.05). No significant differences in Vickers hardness were observed between EBM and SLM in all angles (p<0.05). There were significant differences between 0- and 90-degree in both EBM and SLM, respectively (p<0.05).
Conclusions: Building direction affected the surface properties on both samples fabricated by EBM and SLM. EBM samples showed larger surface roughness than SLM, but the surface hardness of EBM samples was comparable to SLM.