Received: 28 July 2020
Accepted: 2 February 2021
First Online: 2 March 2021
Ethics approval and consent to participate
: All participants provided informed consent verbally. Study information was disseminated to participants both verbally and in written form. This study protocol was approved by the Ethics Committee of Showa University Dental Hospital.
: All authors have approved the publication of this manuscript.
: Motohiro Munakata, Kikue Yamaguchi, Daisuke Sato, Naoko Yajima and Noriko Tachikawa declare that they have no competing interests.