1. Institute of Applied Synthetic Chemistry, Technische
Universität Wien, Getreidemarkt 9/163 MC, 1060 Vienna, Austria
2. Christian-Doppler-Laboratory for Photopolymers in Digital and Restorative Dentistry, Getreidemarkt 9, 1060 Vienna, Austria
3. Anton Paar Germany GmbH, Helmuth-Hirth-Strasse 6, D-73760 Ostfildern, Germany