Funding for this research was provided by:
Yonsei University College of Dentistry (6-2014-0111)
Article History
Received: 17 October 2017
Accepted: 1 March 2018
First Online: 10 March 2018
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.
: This article does not contain any studies with human participants or animals performed by any of the authors. The study was performed with the approval of the Institutional Review Board of Yonsei University Dental Hospital, Seoul, Korea (2-2017-0026). The study was performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments.
: For this type of study, formal consent is not required.