Good health starts with good teeth

3 minute read

Brushing teeth

Laureate Professor Eric Reynolds AO is the inventor of Recaldent, which is sold in 50 countries worldwide with sales surpassing $2 billion dollars. He is president of the International Association for Dental Research. At the University of Melbourne, he is head of the University’s Centre for Oral Health Research and CEO and Director of Research of the Oral Health CRC, and a former head of Melbourne Dental School and Associate Dean of the Faculty of Medicine, Dentistry and Health Sciences. He has published more than 370 peer-reviewed articles and registered 19 patents. He won a Prime Minister’s Prize for Science and Innovation in 2017.

‘Brush your teeth! It could save your life.’ That was the headline on an article about my work a couple of years ago, and it is true. Oral disease is the most widespread health problem on earth, affecting about 3.5 billion people or half the global population. My research has helped establish that periodontitis is linked to dementia, many cancers, cardiovascular diseases, rheumatoid arthritis and other life-threatening illnesses.

I have spent 15 years on my main current project, developing a vaccine against a bacterium from periodontitis that enters the blood stream and can exacerbate or even cause these other diseases, especially Alzheimer’s, and we are working on clinical trials of a vaccine with CSL to eliminate the bacterium from the body.

Eric Reynolds

I think my two great achievements are discovering that a component of cows’ milk could be used to repair teeth and the role of bacteria associated with severe periodontal disease in causing or exacerbating other illnesses. I hope this research has helped the world look differently at the mouth and teeth, and realise how important they are.

My first research was on dental caries, which is tooth decay and starts by loss of minerals in the teeth. I wondered, is it possible to get the minerals back in the teeth before you get cavities? Enamel, the outside of the tooth crown, is very hard and dense. Bacteria in dental plaque ferment sugars to organic acids which dissolve the enamel minerals until you get a cavity, and the only way you can treat that is to drill out the diseased part and fill it. I showed you could repair the early stages of tooth decay if you had calcium phosphate in the right form, and saliva can do that but it is very slow. Milk carries a very similar form of peptide stabilised calcium phosphate to saliva, but has orders of magnitude more of it, and I showed that we could repair the early stages of tooth decay by remineralising or repairing the teeth using this saliva-like peptide calcium phosphate complex from milk. I managed to get a Victorian dairy company to partner with the University of Melbourne, and we developed Recaldent, which now comes in a variety of products. It also gives the teeth a far more natural blue-white colour and lustre.

It really took off with dentists because, if you can do something that’s cosmetic as well as preventive, that takes off faster than something that just prevents disease in the future.

Recaldent products are now sold in over 50 countries worldwide. Sales have passed $2 billion dollars, and from clinical trial data we estimate that these products save dental treatment costs of at least half a billion dollars a year.

Meanwhile, in the ’90s, I started to get interested in periodontal disease. We found that people with severe periodontitis always had a particular bacterium that produced destructive enzymes called proteases. The result of that destruction is loss of bone and the tissue supporting the tooth, allowing the proteases to get into the blood stream and into the brain and other organs. We showed how these proteases completely dysregulate the immune response to produce chronic inflammation, so that it effectively destroys itself at the site of the infection. We were the first to show that the bacterial proteases could clip precursor proteins in the brain to form the plaques and tangles that are associated with Alzheimer’s Disease. This was published in Science Advances in 2019 and became the 36th most-read scientific paper in the world that year.

I’ve been working with CSL on this. The university and CSL have set up a spin-out company called Denteric to take the vaccine to clinical trials, and that’s what we are doing now. We are expanding the trials to look at Alzheimer’s as well as periodontitis. An American company, Cortexyme, has just developed a drug, based on the same principles of targeting the bacterial proteases, that reportedly reduces cognitive decline in people with Alzheimer’s by 57 per cent. But the drug may not be as effective as our vaccine because the problem with a drug is maintaining that effective concentration in terms of chronic infection, whereas our vaccine virtually eliminates the pathogen (in animal trials), so it eliminates the toxin associated with cognitive decline. Also the Cortexyme drug produced liver toxicity in 15 per cent of patients, whereas we believe our vaccine will have no serious adverse effects.

Work is continuing on the caries technology as well, trying to make remineralisation work faster in the dental clinic.

I’ve been at the university for a very long time. I did my PhD here and at the Walter Eliza Hall Institute of Medical research, then a post-doctorate fellowship in the dental school, and it just sort of blossomed. I was successful in getting grant money so I could establish myself as an independent researcher, and in fact I’ve had NHMRC funding ever since. My whole career has been focused on oral diseases – they tend to be trivialised, but the social and economic impact globally is staggering. The global cost is about $750 billion a year. My drive was to get oral diseases recognised, and the only way to do that was good scientific research.

Once it was apparent you could repair the early stages of tooth decay I had a burning desire to do it. And it really does take a burning desire. You have to find the companies capable of funding the millions of dollars required for clinical trials and then you have to convince them to spend lots of money on developing the technology.

We couldn’t achieve all this without partners. There’s an enormous amount of work taking the research, translating it into products, testing the prototypes, then clinical trials. The patenting costs alone are hundreds of thousands of dollars, and the companies pay that – it’s beyond the university. At the time it was almost beyond Australia, which is why I needed multinational companies, but I am delighted that the Australian biotech CSL has supported me for over 20 years and has grown now to the stage of being able to support major initiatives

The reason I became the president of the International Association for Dental Research was to try to get governments and health agencies around the world to see oral diseases as a major problem. Now the World Health Organization has formally recognised oral diseases as major global social and economic burdens, and we are partners in developing a strategic plan to help lower this enormous burden.

As told to Barney Zwartz

Pictured with Laureate Professor Eric Reynolds AO is Coralie Reynolds, who works as part of the research team in the Melbourne Dental School. Photo credit: Eamon Gallagher.

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