Text and Data Mining valid from 2018-03-05
Received: 9 January 2018
Accepted: 14 February 2018
First Online: 5 March 2018
: KS is D.D.S., Ph.D., and FIBCSOMS.
: The study was approved by the ethics committee of Tokyo Dental College (No. 646) (Tokyo, Japan).
: Not applicable
: The authors declare that they have no competing interests.
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