Prof Dr med dent, Dr hc, FDS RCSEd (ad hom) Division of Gerodontology and Removable ProsthodonticsUniversity clinics of dental medicine, University of GenevaCMU, 1 rue Michel-ServetCH-1211 Geneva 4 Switzerland
This is an open-access article distributed under the terms of Creative Commons Attribution-NonCommercial License 4.0 (CC BYNC 4.0), which allows users to distribute and copy the material in any format as long as credit is given to the Japan Prosthodontic Society. It should be noted however, that the material cannot be used for commercial purposes. https://creativecommons.org/licenses/by-nc/4.0/