**4. Conclusions**

The results demonstrated that curcumin could protect cells from high glucose-mediated cytotoxicity, promote osteogenic differentiation of mouse precursor MC3T3 cells in a dose-dependent manner, and significantly improve alveolar bone formation in type 2 diabetic mice. These findings provide new insights into the pathogenesis of diabetes-related osteoporosis and indicate that curcumin may be valuable for prevention and inhibition of diabetes-related osteoporosis, providing a theoretical basis for the clinical treatment of alveolar bone disease in diabetic patients.

**Author Contributions:** All authors had equal contribution to this paper and research. Conceptualization, J.H. and X.Y.; Data curation, J.H. and A.O.A.; Formal analysis, D.L. and B.Z.; Investigation, J.H. and X.Y.; Supervision, Y.L.; Writing—original draft, J.H.; Writing—review and editing, F.L., A.O.A., and Y.L. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the Liaoning Province Natural Science with grant No. (20180550420), and Liaoning province key research and development guidance plan project with grant No. (2019 JH8/10300015).

**Acknowledgments:** The authors would like to express their thanks to teachers and students in the Experimental Centre of School and Hospital of Stomatology, China Medical University, for their continuous help and support.

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