Funding for this research was provided by:
the Scientific Research Fund of National Health Commission of the People’s Republic of China (201502002)
Received: 17 April 2021
Accepted: 21 September 2021
First Online: 12 October 2021
: This study protocol was approved by the Ethics Committee of the Chinese Stomatological Association (Approval no. 2014-003). Informed consent was obtained from all subjects or, if subjects are under 18, from a parent and/or legal guardian.
: Not applicable.
: The authors declare that they have no conflict of interest.