Professor Jennifer Kirkham, who led the study at Leeds University’s Dental Institute, said: ‘The results that have now been analysed show there is a clear benefit, clear repair of those decayed lesions within a month of a single application of the material and the results are highly significant.’

The ‘filling without drilling’ method involves mimicking the conditions that promote the original growth of enamel.

Tooth enamel forms around protein molecules – and the scientists made their breakthrough by reproducing the natural protein in a liquid that can be painted on to a tooth.