Funding for this research was provided by:
The Natural Foundation of Gansu Province,China ((1208RJZA236))
The Key Technology Plane Program of Gansu Province, China ((20YF8FA071))
The Key Technology Support Program of Gansu Province, China ((1604FKCA089).)
Received: 15 January 2022
Accepted: 2 April 2022
First Online: 12 April 2022
: This is a retrospective cross-sectional study approved by the Institutional Ethical Committee (NO LZUKQ-2021-021) at the Hospital of Stomatology in Lanzhou University, China.
: Not applicable.
: The authors declare that they have no competing interests.