Iztok Štamfelj1,2. 1. Department of Dental Diseases and Normal Dental Morphology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia. iztok.stamfelj@mf.uni-lj.si. 2. Department of Operative Dentistry and Endodontics, University Medical Centre Ljubljana, Ljubljana, Slovenia. iztok.stamfelj@mf.uni-lj.si.