# Surface Analysis of 3D (SLM) Co-Cr-W Dental Metallic Materials
## 4 Conclusions  
Analyzing the results obtained from the surface investigation of some 3D printed metallic samples, we present the follow conclusions:  
* After the 3D printing process, the dental material samples made through SLM presented many semi-melted particles that increased the contact surface of the elements. Using different blasting media, the 3D printed alloy surface could be cleaned and its roughness modified in order to fulfill the medical application requirements.
* The oxidation process took place on the surface of all of the samples, and unstable compounds based on sandblast materials were identified.
* The 50 \(\upmu\)m--0 (1, 2) presented a higher roughness than the 25 \(\upmu\)m--0 (1, 2) sample for the Ra, Rq, and RT parameters, regardless of the condition of the samples' surfaces.
* The droplet adhesion characteristics were modified with the sandblast operation.
* The sandblast operation considerably increased the samples' hardness, especially in the case of 25 \(\upmu\)m--0 (1, 2).
* Even the material is consecrate in literature, and, in laboratory practice, further medical tests can be considered in order to confirm the implications of surface preparation, especially on 3D complex structures.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Sample** & **Test 1** & **Test 2** & **Test 3** & **Test 4** & **Test 5** & **Average HV Value** \\ \hline
25 \(\upmu\)m—0 & 404.3 & 406.1 & 437.5 & 378 & 411.7 & 407.52 \\ \hline
25 \(\upmu\)m—1 & 391.7 & 470.4 & 456.8 & 468 & 429 & 443.18 \\ \hline
25 \(\upmu\)m—2 & 479.7 & 499.4 & 528.4 & 514 & 475 & 499.3 \\ \hline
50 \(\upmu\)m—0 & 468 & 437.5 & 463.5 & 472.7 & 463.5 & 461.04 \\ \hline
50 \(\upmu\)m—1 & 459 & 472.7 & 484.5 & 470.4 & 472.7 & 471.86 \\ \hline
50 \(\upmu\)m—2 & 477.4 & 470.4 & 481.2 & 484.5 & 473.8 & 477.46 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Micro Vickers hardness of the samples.  
**Author Contributions:** Conceptualization, E.-R.B., C.B., and N.C.; methodology, R.C. and G.Z.; software, R.C. and A.S.; validation, A.M. and A.V.; investigation, N.C., C.B., and E.-R.B.; resources, R.C.; writing--original draft preparation, N.C.; writing--review and editing, R.C. and G.Z.; visualization, A.M.; supervision, N.C. All authors read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by \"[PERSON]\" University of Medicine and Pharmacy Iasi grant number 27500, \"Influence of 3D printing/Selective Laser Melting processing parameters on surface quality and bonding level between metal/ceramic components in dental prostheses.\" And The APC was funded by \"[PERSON]\" University of Medicine and Pharmacy Iasi.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Acknowledgments:** This work was supported by a young-researcher grant from \"[PERSON]\" University of Medicine and Pharmacy Iasi, project number 27500, \"Influence of 3D printing/Selective Laser Melting processing parameters on surface quality and bonding level between metal/ceramic components in dental prostheses.\"  
**Conflicts of Interest:** The authors declare no conflict of interest.