Issa, Julien, Chair of Practical Clinical Dentistry, Department of Diagnostics, Poznań; University of Medical Sciences, Bukowska 70, 60-812 Poznan, Poland Issa, Julien, 1) Chair of Practical Clinical Dentistry, Department of Diagnostics, Poznań University of Medical Sciences, Bukowska 70, 60-812 Poznan, Poland; 2) Doctoral School, Poznań University of Medical Sciences, Bukowska 70, 60-812 Poznan, Poland