**5. Conclusions**

Within the limitations of the present study and based on the findings, it can be concluded that custom-printed and -milled titanium post and cores revealed significantly higher retention and bonding to resin cement than CMZPCs and similar to the control group. The CMZPCs revealed the lowest retention and adhesion to the resin cement. Therefore, the use of titanium in the fabrication of printed and milled post and cores was effective in terms of retention and could be an alternative material of choice to non-precious alloys. Further studies with in vivo testing are required to confirm the conclusions of this study.

**Author Contributions:** Conceptualization, H.A., R.J., M.T.K., S.A.V. and S.D.; methodology, H.A., R.J., M.T.K., S.A.V., S.D. and A.A.A.; software, H.A., S.A.V., S.D. and A.A.A.; validation, H.A., R.J., M.T.K., S.A.V. and S.D.; formal analysis, H.A., R.J., M.T.K., S.A.V., S.D. and A.A.A.; investigation, H.A., R.J., M.T.K., S.A.V. and S.D.; resources, H.A., R.J., M.T.K., S.A.V., M.E.S., S.J. and S.D.; data curation, H.A., R.J., M.T.K., S.A.V. and S.D.; writing—original draft preparation, H.A., R.J., M.T.K., S.A.V., S.D., M.E.S., S.J. and A.A.A.; writing—review and editing, H.A., R.J., M.T.K., S.A.V., S.D., M.E.S., S.J. and A.A.A.; visualization, H.A., R.J., M.T.K., S.A.V., M.E.S., S.J. and S.D.; supervision, H.A., R.J., M.T.K., S.A.V. and S.D.; project administration, H.A., S.A.V., S.D., M.E.S., S.J. and A.A.A. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** IRB# 5220414.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data that support the findings of this study are available from the corresponding authors upon reasonable request.

**Acknowledgments:** The authors thank and acknowledge Ozgul Yasar-Inceoglu (California State University, Chico, CA, USA) for support with scanning electron microscopy in this investigation.

**Conflicts of Interest:** The authors declare no conflict of interest.
