Funding for this research was provided by:
Received: 16 November 2020
Accepted: 25 January 2021
First Online: 22 February 2021
Ethics approval and consent to participate
: The study protocol including the extended observation period was approved by the ethics committee of the Heinrich Heine University, Düsseldorf, Germany.
: Formal consent was obtained by all participants.
: Frank Schwarz and Jürgen Becker have received research grants and have been invited to lecture for Geistlich Pharma AG, Wolhusen, Switzerland. Frank Schwarz is an executive board member of the Osteology Foundation, Lucerne, Switzerland.