Fillings could be a thing of the past as scientists say they have found a way to grow back tooth enamel.

Enamel, a highly mineralised substance that acts as a barrier to protect the tooth, can become susceptible to degradation, especially by acids from food and drink.

Despite being the hardest tissue in the body, it cannot self-repair, leaving people exposed to cavities and in need of fillings.

But scientists in China have found that mixing calcium and phosphate ions - two minerals which are found in enamel - with the chemical trimethylamine in an alcohol solution causes enamel to grow with the same structure as teeth.

The discovery has not yet been proven to work in the "hostile environment" of the mouth, but experts say regrown tooth enamel may be tested in people in the near future.


When the mixture was applied to human teeth, it repaired the enamel layer to around 2.7 micrometres of thickness. It also achieved the same structure of natural enamel within 48 hours.

Dr Zhaoming Liu, a co-author of the study from Zhejiang University in China, said: "Our newly regenerated enamel has the same structure and similar mechanical properties as native enamel.

"We hope to realise tooth enamel regrowth without using fillings which contain totally different materials and we hope, if all goes smoothly, to start trials in people within one to two years."

He said past attempts to regrow enamel by using a range of materials such as composite resins, ceramics and amalgam had failed to achieve permanent repair because of the imperfect combination between these foreign materials and the native enamel.

The researchers behind the study, published in the journal Science Advances, managed to defeat this problem by developing a way to produce tiny clusters of calcium phosphate - the main component of enamel - with a diameter of just 1.5 nanometres.

Image: Despite being the hardest tissue in the body, enamel cannot self-repair

With the presence of trimethylamine, the clusters were prevented from clumping.

Currently, nothing can be done to repair damaged teeth in the dentist's chair apart from fillings or crowns. Many scientists are looking for ways to grow back enamel.

Last year, Researchers at Queen Mary University of London said they had developed a way to grow mineralised material.

The team found a protein able to trigger the growth of crystals, in a similar way to how crystals grow when dental enamel develops in the body.

Lead author Professor Alvaro Mata said the "key discovery" had been finding a way to exploit proteins to control and guide the process of mineralisation.

He said: "Through this, we have developed a technique to easily grow synthetic materials that emulate such hierarchically organised architecture over large areas and with the capacity to tune their properties."