Funding for this research was provided by:
China Scholarship Council (201109180017)
Beijing Stomatological Hospital , School of Stomatology, Capital Medical University
Article History
Received: 28 October 2019
Accepted: 23 January 2020
First Online: 31 January 2020
Ethics approval and consent to participate
: Not applicable.
: Not applicable.
: The authors declare that they have no competing interests.