Qin, Yuandong
Chen, Lin
Li, Jianbo
Wu, Yunyun
Huang, Shaohong
Article History
Received: 5 April 2021
Accepted: 25 October 2021
First Online: 8 November 2021
Declarations
:
: This study was approved by the Stomatological Ethics Committee of the Chinese Stomatological Association on July 9, 2014 (Approval No.: 2014-003). All procedures performed in the study involving human participants were in accordance with the Helsinki declaration. Informed consent was obtained from all the participants and from legal guardians of illiterate participants.
: Not applicable.
: The authors declare that they have no competing interests.