Dan earned his Consultant accreditation in 1983. He is a registered orthodontic specialist.
His orthodontic training was at University of Liverpool and University College Cork. He is a visiting lecturer to a number of universities and gives lectures at conferences both in Ireland and abroad.
He is a member of the Orthodontic Society of Ireland , The American Association of Orthodontists, The European Orthodontic Society and the British Orthodontic Society.
He has had a private practice in Tralee since 1980.