Received: 15 January 2020
Accepted: 25 March 2020
First Online: 10 April 2020
Ethics approval and consent to participate
: The local Ethics Committee denied the need for a formal approval for using irreversibly anonymized teeth. All donors had given their verbal informed consent to the use of their extracted, anonymized tooth/teeth for research purposes.
: Not applicable.
: Sigrun Eick is a member of the editorial board for BMC Oral Health, but otherwise had no role in the publication process of this manuscript. The other authors declare that they have no competing interests.