Funding for this research was provided by:
BARMER AöR, Berlin
Received: 20 April 2020
Accepted: 6 August 2020
First Online: 20 August 2020
Compliance with ethical standards
: Michael Raedel intentionally serves as a dentistry expert for the BARMER on a freelance basis. Besides that, he has no conflict of interest. Barbara Noack declares that she has no conflict of interest. Heinz-Werner Priess declares that he has no conflict of interest. Steffen Bohm declares that he has no conflict of interest. Michael H. Walter declares that he has no conflict of interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Ethical approval was waived by the local Ethics Committee of TU Dresden.
: For this type of study, formal consent is not required.