Received: 23 November 2018
Accepted: 18 December 2018
First Online: 11 January 2019
Ethics approval and consent to participate
: Not applicable. But, for the clinical pictures included, we have received a statement of ethics approval was provided by the Department of Oral and Maxillofacial Surgery at Seoul National University Dental Hospital, with the approval of the Institutional Review Board of Seoul National University (S-D20170024).
: Written informed consent was obtained from the patients for the publication.
: The authors declare that they have no competing interests.
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