[2] In 1978, he was appointed assistant professor and senior research fellow in the Department of Immunology at the Mayo Clinic in the United States,[3] and completed the fellowship in 1979.

[5][7] His experience has also included coordinating conferences and university departments, managing grants, finances and research, and teaching.

It was launched in 2011 at Tylney Hall in Hampshire[8] and has become widely used as a medical tool for assessing and monitoring dry mouth.

[1] In 2020, he co-authored a review which proposed using povidone-iodine to reduce cross-infectivity of COVID-19,[16] and highlighted the role of saliva in the transmission of the disease.

[1] He also continues to support students of the world's oldest rugby club, Guy's Hospital RFC.

[22] He has been an author, co-author, editor and co-editor of a number of publications including nine books, over 240 peer-reviewed research papers and 160 other works on various aspects of oral and maxillofacial medicine.