Funding for this research was provided by:
National Research Foundation of Korea (NRF-2017R1C1B5075858)
Text and Data Mining valid from 2019-01-07
Received: 18 November 2018
Accepted: 11 December 2018
First Online: 7 January 2019
Ethics approval and consent to participate
: This study conforms to the Declaration of Helsinki on medical protocol and ethics and was approved by the regional Ethical Review Board of Yonsei University Dental Hospital Institutional Review Board (IRB 2-2014-0031).
: Not applicable.
: The authors declare that they have no competing interests.
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