Tooth enamel is the hardest substance in the human body and the secret of its strength is its composition of tiny crystals or platelets aligned in the same direction. Scientists have found a way of mimicking this structure to produce super-tough composite materials that could be used in dentistry and other areas of medical science. The recipe involves mixing magnetised micro-platelets of a ceramic substance, such as aluminium oxide, with a liquid polymer. The mixture is put into a mould and as it sets, a magnetic field is applied, causing the platelets to align. Once set, the material is baked at a high temperature. Pictured is a false-coloured cross section of an artificial tooth – the two layers, enamel (blue) and dentine (purple) are created by changing the magnetic field while the mixture is setting from the outside in, so the platelets are orientated in different directions.
Written by Mick Warwicker
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