Dr. Mark Thomas Sebastian passed his state examination and doctorate at the Private University of Witten-Herdecke in 1993. His assistant time lasted until 1996 with study visits to Brazil, USA and South Africa. From 1996 he was a junior partner specializing in periodontology and implantology in the practice of Dr. Josef Schmidseder, Munich, one of the first German pioneers in esthetic dentistry. From 1996–2001 he was a scientific editor in the "European Journal of Aesthetic Dentistry". During this time he gave lectures on plastic periodontal surgery and published the book "Periodontology – State of Science, American Academy of Periodontology". In 1999 he founded his own practice in Munich with a focus on esthetic restorative dentistry, periodontology and implantology. Since 2000 he has been a scientific member of the editorial team of the journal “Quintessenz Zahnmedizin” published by Quintessence Publishing, Berlin. He is one of the founding members of the first European “Seattle study club SSC” in Tegernsee, 2008. The German Society for Esthetic Dentistry DGÄZ named him in 2014 as a “Specialist in Esthetic Dentistry and Function”. He completed the master's degree in the function of the chewing organ with Professor Slavicek, Vienna, in 2015. Since then, he has lectured for orthopedic surgeons on the connection between dentistry, orthopedics and bruxism. Since 2016 he has been a member of the "Invisalign Academic Aesthetic Advisory Board". Since then he has held international lectures and courses on splint orthodontics, esthetic dentistry and function.