Peter A. Kessler is Professor and Head of the Department of Cranio-Maxillofacial Surgery, Maastricht University Medical Center (MUMC+), Maastricht, The Netherlands.Dr. Kessler completed his studies in dentistry and medicine at the Friedrich-Alexander-University of Erlangen-Nuremberg in 1986 and 1994 respectively (Prof. Dr. Emil Steinhäuser), where he habilitated in 2001. He qualified as Specialist in Oral and Maxillofacial Surgery in 1999 under Prof. Dr. F.W. Neukam and holds a qualification in plastic surgery (2003). From 1999 to 2001 he worked as a specialist at the Department of Oral and Maxillofacial Surgery, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen (Prof. Dr. F.W.Neukam); he then became Senior Lecturer and Vice-Director at the clinic before taking up his current position in Maastricht in 2007.Nicolas P. Hardt was Professor and Head of the Clinic for Cranio-Maxillofacial Surgery, Kantonsspital, Lucerne (LUKS), Switzerland from 1974until 2007. Dr. Hardt graduated in Dentistry and Medicine at the University of Bonn, Germany, and subsequently completed a residency at the Clinic for Cranio-Maxillofacial Surgery in Bonn (Prof. Dr. Eberhard Krüger). In 1970 he was appointed Senior Assistant in the Clinic for Cranio-Maxillofacial Surgery at the University of Berne in Switzerland (Prof. Dr. Otto Neuner). In 1973 he was visiting maxillo-facial Surgeon in the Centre for Cranio-Maxillofacial Surgery / Queen Mary’s-Hospital - Roehampton/London (Sir Norman Rowe). He then qualified by Prof. Dr. Emil Steinhäuser (Erlangen/Nürnberg) as a Specialist for Cranio-Maxillofacial Surgery in Switzerland (1974) and Germany (1975) and the EU (1979) and holds a qualification in Plastic Surgery (1980). Dr. Hardt completed his Habilitation by Prof. Dr. Hugo Obwegeser (University Clinic for Cranio-Maxillofacial Surgery of Zürich) in 1981 and became a Full Professor at the University of Zurich in 1990.Kensuke Yamauchi is Professor and Head of the Department of Oral and Maxillofacial Reconstructive Surgery, Tohoku University, Sendai, Japan (Head: Prof. Tetsu Takahashi). Dr. Yamauchi graduated in Dentistry at Tohoku University in 2001 and completed a residency at the Kagawa Prefectural Central Hospital in Kagawa (Dr. Masaharu Mitsugi). He was appointed assistant professor at the Department of Oral and Maxillofacial Reconstructive Surgery of Kyushu Dental College (Prof. Tetsu Takahashi) until 2012. He also visited the Department of Cranio-Maxillofacial Surgery, Maastricht University Medical Center (Prof. Dr. Peter Kessler) from 2011 to 2012. He moved to the Department of Oral and Maxillofacial Surgery, Tohoku University (Prof. Tetsu Takahashi) in 2012, and became a Lecturer and Vice-Director of Dental Implant Center in 2013 and taking up his current position in Tohoku University in 2022.