"Once around the world ..." Unsolicited congress invitationsvia e-mail

For some years now, scientifically active people have been the recipients of e-mails that advertise for their participation in two-, three- and sometimes even four-day conferences. It is not uncommon for the recipients to be offered the opportunity to attend as speakers or chairpersons. Specialist literature on this topic can easily be overviewed, as it is rather limited [1–10, 13, 17, 18, 20, 21, 23–26, 29–35]. For most publications, short articles, such as editorials or letters to the editors, are involved. There are very few data-based analyses of this phenomenon [6, 27]. In the only article in the field of dentistry to date, the British periodontist Peter Heasman describes his experiences with the organizers of such meetings.