Dr. Leonidou studied at the university "Carol Davila" in Bucharest, where he became a Dental Surgeon.

After graduating as a Dental Surgeon, he started his post-graduate training in becoming an Orthodontist.

For 3 years he got his training exclusively in Orthodontic cases at the "Carol Davila" Orthodontic state clinic in Bucharest. He also started working at the "American Medical Center" of Bucharest.

Dr. Leonidou took his training a step further by studying alongside some of the bigger names in world Orthodontics such as , Prof. Dr. Dragos Stanciu, Prof. Dr. Richard P. McLaughlin, Prof. Dr. Andre Horn, Prof. Dr. Wolfgang Gruner and Prof. Dr. Larry Brown in Bucharest, Romania, Prof. Dr. William Proffit, Prof. Dr. David Sarver, Prof. Dr. Dirk Wiechmann, Prof. Dr. Hugo DeClerk, Prof. Dr. Franz Van Der Linden, Prof. Dr. Bjorn Zachrisson and Prof. Dr. Dan Grauer in Barcelona, Spain and was part of the TWEED International Foundation For Orthodontic Research Course, Tucson, Arizona, U.S.A in 2011 with Prof. Dr. Herbert Klontz

He speaks fluently Greek, Romanian and English.

Dr Leonidou was born in Limassol, Cyprus. e studied at the university Carol Davila in Bucharest, where he earned his degree as a Dental Surgeon. After graduation, he started working in a private clinic of Bucharest. Dr Leonidou always had an interest in children’s health, which made him spend his free time volunteering at Bucharest Children’s Hospital of Pediatric Dentistry, doing his best helping Hospital’s needs. During that time Dr Leonidou discovered a special bonding with the children which made him extend his studies to a Paediatric Dentist degree. Dr Leonidou worked in the clinic alongside the president of A.N.S.P.R. (Pediatric Association of Romania), Prof.Dr.Rodica Luca. Dr Leonidou is a member of the European E.A.P.D. organisation. He has a very good knowledge of Greek, Romanian and English language.