Text and Data Mining valid from 2018-02-06
Received: 31 August 2017
Accepted: 21 December 2017
First Online: 6 February 2018
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: Before starting this research, ethical approval of the Ethical Committee of Krondent Dental Clinic was obtained: approval no. 101E /30.11.2015. All patients had signed a consent form at the moment they were selected for this study.