We speak with Saroash Shahid who explains why a new varnish inspired by techniques used to protect bridges from adverse weather could be the answer to the UK’s caries crisis.
Researchers at Queen Mary University of London have developed a new dental treatment, called Varnish VLC, to protect the teeth from decay and acid erosion, using cutting-edge civil engineering technology used to create the paint that covers the Forth Bridge in Scotland.
The flake glass technology used to create the varnish has been used to protect tanks, vessels and pipelines from corrosion due to its capabilities to protect against moisture and other harsh elements. It has also been used in the maintenance of steel bridges, including the Forth Bridge, providing up to 25 years of protection.
Dr Saroash Shahid, reader in dental biomaterials at Queen Mary and lead researcher on the project, describes how the varnish was developed and what he hopes it can achieve:
What was the inspiration behind the varnish?
I think the main inspiration came from looking at current treatment options for early caries. They generally fail in terms of protection from acid or wear. For example, fluoride varnishes rely purely on a chemical process, which can be very slow. If you look at resin-based options, tend to have poor wear resistance and don’t offer strong acid protection.
Protection from wear and protection from acid penetration are the two key components you want when protecting a tooth from caries progression: that’s when we started looking around and came across flake glass, which is used in deep-sea oil pipelines to protect against wear and corrosion. What they call corrosion, we call erosion – but essentially, it’s the same thing.
The oral cavity is a harsh environment and not very different from the harsh environment of the deep sea. One moment someone might consume something hot, then something cold, followed by an acidic drink and then something neutral. It’s constantly changing.
We also came across a BBC article about the Forth Bridge from a number of years ago. It explained how they had struggled to paint it for so many years and that the paint just doesn’t work. Then they used flake glass in a paint or epoxy coating, and that’s now expected to last 25 years. That was remarkable. Since then, it’s still holding up on the Forth Bridge.
‘Another thing we did was match the refractive index of the flakes to that of the resin to create a very translucent or even transparent coating. This is great because it doesn’t affect the aesthetics of the tooth’
That’s when we began exploring what flake glass was and started working on incorporating flake glass it into dental applications around 2010–2011. We couldn’t go for epoxy because it has a different chemistry and takes very long to set. Instead, we adapted it into light cured resin formulations similar to dental composites) to be used in dentistry and developed it into a coating to protect teeth – just like it protects the Forth Bridge.
How much development went into it?
We had to optimise various things to reach the final product. It’s not just about putting flakes into the resin – it’s also about optimising how well the flakes align, because the alignment is absolutely key.
When we paint the coating to the tooth surface, we want the flakes to stack on top of each other – the only way they effectively protect the tooth is if they lie flat. To achieve this, you need the right ratio of flakes to resin, as well as the right viscosity.
Another thing we did was match the refractive index of the flakes to that of the resin to create a very translucent or even transparent coating. This is great because it doesn’t affect the aesthetics of the tooth.
It required a lot of optimisation across all these factors to finally get it to a product.
How effectively does it mimic enamel?
If you look at enamel structure, it’s protecting the underlying living dentine from everything and it’s a very hard tissue. Enamel also has a highly organised structure – hydroxyapatite crystals are very well aligned. This is what gives enamel its properties in terms of translucency, and protection from wear and acid.
That’s what we’ve tried to mimic as much as possible in this new material by adapting flake glass for dentistry. The key, critical feature of the product is that these are self-aligning flakes. As you apply them to the tooth, they stick and align parallel to the surface. They stack on top of each other like a deck of cards.
If you think of a deck of cards, the surface is very smooth. Because you’ve got layers of cards, this makes it really difficult for acid or any moisture to diffuse through.
A six-month trial is currently underway. What are your hopes for the product?
I’m very optimistic. The unique selling point of the product is its longevity in protecting against acid and wear. It has a wide range of potential applications.
In vitro lab tests show it lasts longer than any existing commercial products currently used to protect teeth. As a result, I think it will be very useful in preventing the progression of early caries lesions into full-blown caries, in paediatric or even elderly patients.
In the elderly, for example, tooth sensitivity can occur for a number of reasons – wear, nutrition or gingival recession. Varnish VLC can be applied on the exposed root surfaces to prevent dentine hypersensitivity.
Follow Dentistry.co.uk on Instagram to keep up with all the latest dental news and trends.
