Funding for this research was provided by:
National Natural Science Foundation of China (51672009, 51972005)
Natural Science Foundation of Beijing Municipality (7192227)
School of Stomatology, Peking University (PKUSSNCT-19A05)
Received: 29 September 2020
Accepted: 11 March 2021
First Online: 19 March 2021
: This study was a retrospective study conducted in accordance with the declaration of Helsinki (1975, as revised in 2000). The study protocol was approved by the local ethics committee (Institutional Review Board of Peking University School and Hospital of Stomatology, approval number: PKUSSIRB-201,948,110). All patients provided informed consent after a comprehensive consultation.
: Written informed consent to publish individual person’s data (images) were obtained.
: The authors declare that they have no competing interests.