Dermot Strahan was head of the department of periodontology at the Institute of Dental Surgery, Eastman Dental Hospital, London. He was born on 24 February 1933 and grew up in Belfast, Northern Ireland. He attended Campbell College, Belfast and went on to study dentistry at Queen’s University, qualifying in 1956. He worked in general dental practice for a while and then moved to England in 1960. He joined the department of periodontology at the Eastman Dental Hospital, becoming acting head of the department and then the permanent head. He was responsible for bringing hygiene training to the Eastman and also organised and ran a wide range of postgraduate programmes, including a one-year MSc in periodontology and short courses for general dental practitioners and service personnel. With Ian M Waite he wrote *A colour atlas of periodontal surgery* (London, Wolfe Medical, 1987) and with H Donald Glenwright *Periodontology* (London, Mosby-Wolfe, 1994). He was involved with the British Society of Periodontology from the 1960s and was president from 1975 to 1976. At the Faculty of Dental Surgery of the Royal College of Surgeons of England, he gained his fellowship in 1961 and was a member of the board for 12 years, including serving as vice dean. Outside his professional life, he enjoyed golf and from an early age was a member of Knock Golf Club, close to his childhood home. He married Anne T Parker in 1966. Strahan died on 7 June 2019. He was 86.