For 30 years, Mike Hayes was a valued member of the Department (now School) of Biochemistry. He was a gifted and dedicated teacher who redesigned and ran, with considerable success, the “Biochemistry and Oral Biology” course for first-year dental students. He also undertook both fundamental and applied research into dental plaque; and later in his career, took on a range of senior roles including Dental Preclinical Dean (twice) and becoming an Assessor for the Teaching Quality Assessment of (UK) Universities.

Born in Leeds on 5 September 1939, he was sent to boarding school at the age of eight – initially, Barborough Hall in Derbyshire and then, at 11, he moved to the Salesian College, Oxford. Straight from Salesian College, Mike went to University College London to study Dentistry. After qualifying in 1963, he joined a general dental practice in Berkshire where he met Jan, his future wife, then a dental hygienist. Mike found that he was more interested in the science underpinning dental surgery than its daily practice! So, after a couple of years, he gave up his post, completed the two-year MSc course in Biochemistry at University College London and joined the Department of Dental Sciences, University of Liverpool, as a Research Associate. He enrolled for a PhD and studied the adherence of plaque to teeth resulting in a short Nature paper and some six other publications. In 1969, after receiving his PhD, Mike married Jan, and they spent a year in the University of Manitoba, Winnipeg, before Mike was appointed to a lectureship in the Department of Biochemistry here in Bristol in 1970.

At that time, the “Biochemistry and Oral Biology” course for dental students was not universally popular as the students did not always grasp its relevance to dentistry. One of Mike’s major achievements was the major reform of the whole course with the introduction of many topics of dental interest in the lecture and practical classes. This was a considerable undertaking as a wide range of subject matter was covered. All the lectures, practical classes and tutorials were taught by Mike together with just one other member of staff. For many years, this was Dr John McGivan, one of the authors of this obituary. He experienced at first-hand the impressive increase in popularity of the course with dental students following the many changes made by Mike.

With funding from a series of MRC project grants, Mike and his research students continued the study of dental plaque, exploring in detail the factors that govern the production of organic acids from the metabolism of sucrose; – these short-chain acids are the main agents of tooth decay. Most notably, their studies showed that certain long- and medium-chain-length fatty acids (such as nonanoic acid) inhibited both dental plaque growth and acid production, raising the possibility that incorporation of such fatty acids into toothpastes or mouthwashes may reduce dental caries. A patent was obtained, and further studies were initiated, focussed mainly on the effects of added sodium nonanoate to mouthwashes. These were funded by Cadbury, Tate & Lyle and Mars in the UK and Warner-Lambert, a major producer of mouth and throat medicines, in the USA. However, the approach appeared to have only limited efficacy and did not take off commercially. Interestingly, after nearly 40 years since Mike published his findings, the extent to which diet-derived fatty acids reduce dental plaque formation has recently received renewed attention. Although Mike was no longer a practicing dentist, his advice on dental matters was often sought by his colleagues. Dick remembers asking about two of his front teeth loosened by a wild swipe of his opponent in a game of squash. After a quick and expert inspection, Mike declared “Your teeth will be fine if they were kept to light duties for a week”. Indeed, 50 years later, they remain in good fettle.

Mike’s expertise in the teaching of dental biochemistry/oral biology was increasingly sought by other UK universities, both as a consultant and as an external assessor. He spent short periods abroad including at the University of Dar-es-Salam (Tanzania), University of Caracas (Venezuela) and University of Granada (Spain) advising on and setting up new courses.

Mike was also selected to be an Assessor in the Teaching Quality Assessment (TQA) whereby, in the late 1990s, teaching in UK universities was assessed. It was announced that the teaching in the separate Departments of Biochemistry and Pathology & Microbiology would be assessed together by this process in the autumn term of 1999. This happened to be a fraught time for the Department of Biochemistry as its research was also being assessed (by the equally demanding Research Excellence Assessment), while also being embroiled in two major building projects and experiencing the loss of senior academic staff due to retirement (including that of Mike). Dick, the then hard-pressed Head of Department, remembers well the feeling of great relief when Mike kindly agreed to put off his retirement by a term and head up the response of the Biochemistry Department with Dr David Yates, Departmental Administrator. Mike was the only member of either Department who was a TQA assessor and so fully understood what was expected. Indeed, he and David, together with Dr Gilbert Howe and Dr John Grinstead from Pathology & Microbiology, proved to be an excellent team and the highest possible mark of 24/24 was obtained. It was really fitting that Mike’s academic career should end on such a high note.

Mike was a very practical man able to renovate in turn the family homes in Westbury Park and Kingsdown in which they brought up their two sons, Adam and Jake, and a niece, Lucy. Jake now lives in Bradford-on-Avon with his family and works as a writer and TV producer. Lucy lives on the Isle of Man with her family and runs the Manx Deaf Society. Adam moved with his son to Spain in the mid-1990s, working as an artist and craftsman. In fact, they live in the same village near Granada as a small cottage Mike and Jan bought in the early 1980s, in which Mike and his family spent many happy holidays. Mike and Jan planned to spend much more time in Spain following Mike’s retirement at the end of 1999, and they bought a farmhouse with a considerable amount of land close to their holiday cottage. This was, by far, Mike’s most ambitious renovation project and took up the first four years of his “retirement” to complete. Jan and Mike separated in 2014 and the farmhouse was sold. Mike moved back to Bristol and settled in sheltered accommodation. Sadly, he was diagnosed with dementia in 2020 and lung cancer a year later. His son Jake has told us: “He has always kept up with the latest developments in science and what really sparked his enthusiasm was talking about science and explaining complex ideas to like-minded people. In the past, he got a huge amount of pleasure working with his PhD students. Even in his last months when fading memory made it difficult for him to concentrate on reading, he still got pleasure when I bought him a copy of the New Scientist”.

Mike died on 22 September 2022, leaving his wife Jan and their two sons, Adam and Jake.

We are very grateful for the invaluable help of Jake Hayes in supplying much of the information on which this obituary is based.