Text and Data Mining valid from 2019-08-06
Received: 18 June 2019
Accepted: 29 July 2019
First Online: 6 August 2019
Ethics approval and consent to participate
: The study was approved by the Medical Ethics Committee of Kyushu Dental University (No. 16–42). Written informed consent was obtained after the details of the study were explained to the participants.
: Not applicable.
: The authors declare that they have no competing interests.