Funding for this research was provided by:
West China Hospital, Sichuan University (2018HXBH013)
Article History
Received: 15 February 2020
Accepted: 12 May 2020
First Online: 27 May 2020
Compliance with ethical standards
:
: The authors, Caiqi Cheng, Zhisen Ai and Linyong Zhao declare that they have no conflict of interest.
: The study was approved by the Ethics Committee of West China College of Stomatology, Sichuan University. Informed consent was waived because all data involving the individual participants included in the study were from the public database and their private information was concealed prior to evaluation.