Text and Data Mining valid from 2019-04-08
Received: 25 January 2019
Accepted: 24 March 2019
First Online: 8 April 2019
Compliance with Ethical Standards
: We declare that we have no conflict of interest.
: The study protocol was approved by the Internal Review Board of the Department of the College of Stomatology at Guangxi Medical University.
: All patients signed informed consent forms.