Funding for this research was provided by:
Research Fund of Peking University, School of Stomatology (PKUSS20140204)
Medical-Bioscience-interdisciplinary Seed Funding of Peking University (BMU20140449)
Received: 19 October 2018
Accepted: 25 January 2019
First Online: 18 February 2019
Ethics approval and consent to participate
: The study design, protocol, and informed consent forms were undertaken with the understanding of Declaration of Helsinki and were approved by the Human Research Ethics Committee of the School of Stomatology, Peking University, China (PKUSSIRB -2,012,042). Written informed consent was obtained from all individual participants included in the study.
: Not applicable.
: The authors declare that they have no competing interests.
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