Didier Fillion has been practicing lingual orthodontics exclusively for 36 years. He has held courses in Lingual orthodontics around the world and lectured in all important adult orthodontic congress. Founding member and Honorary President of the French Lingual Orthodontic Society (SFOL) Founding member of the European Society of Lingual Orthodontics (ESLO) Founding member and 1st President of the World Society of Lingual Orthodontics (WSLO) Course Director of the two-year Lingual Orthodontic Post-graduate program at Paris-V University ( France) from 1996 to 2010 Co-Director of the Lingual Orthodontic Fellowship at the University of Texas, San Antonio, USA. (2018-2021) Course Director of the International School of Lingual Orthodontics of Paris