Sia is principal of three Dental Practices across London as well as holding the post of Honorary Associate Clinical Professor at the University of Warwick. He is also a visiting Lecturer at the University of Florence, Italy. He is a specialist in Prosthodontics and runs a multi disciplinary practice in Wimpole Street, London W1. He has been part time lecturer both in conservative dentistry, which is now called restorative dentistry and part time lecturer in Oral and Maxillo-facial surgery at the Royal London Hospital.
Sia also does consultancy dental work for Chelsea Football Club. Sia has lectured extensively regarding Dental Bleaching in the UK and internationally.