Scientists are step closer to making teeth from scratch after 'hybrid tooth' is made in mouse's mouth


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The Independent Online

Scientists have taken a step closer to growing human teeth from scratch using cells taken from a patient’s mouth. They envisage that missing or diseased teeth could one day be replaced by freshly-grown, living teeth.

A “hybrid” tooth made from a mixture of human gum cells and mouse embryonic cells has been grown in laboratory mice to test a method that might in the future be adapted to become an alternative to dental implants.

Researchers believe that growing bioengineered teeth from a patient’s own cells could revolutionise dentistry, which in recent years has focussed on replacing damaged or missing teeth with porcelain crowns attached to metal implants inserted into the jaw.

“The idea is to identify cells that you can put together and will grow into an immature tooth, which will develop into a mature tooth after it is inserted into the patient’s mouth,” said Professor Paul Sharpe of King's College London

The “bio-tooth” produced by mixing human gum cells with embryonic mouse cells formed viable roots with good periodontal ligaments which normally anchor healthy teeth to the jawbone, Professor Sharpe said.

As well as anchoring teeth, the periodontal ligaments act as shock absorbers during chewing. Metal implants are rigidly fixed to the bone and do not have shock absorbers, which can damage the jawbone over time, he said.

The study, published in the Journal of Dental Research, is the first demonstration of a bio-tooth grown by combining a human gum cells with embryonic cells of a mouse.

The gum cells were epithelial cells, which formed the outer hard enamel of a tooth, while the mouse cells were mesenchymal cells, which form the inner dentine and tooth pulp, Professor Sharpe said.

The hybrid tooth could never be used in human transplant dentistry because it contains animal-derived material. It was only created to demonstrate that the procedure can produce a viable tooth, he added.

The next step is to identify a source of mesenchymal cells in the patient that could be combined with epithelial cells to make a pure-human immature tooth which can then be transplanted into the patient’s jaw as a living replacement for a lost tooth, he said.

“I see this as a step forward on what has been done before. It is an advance, and these cells work when put together in this way but we need to find a source of human mesenchymal cells,” Professor Sharpe said.

“Mesenchymal cells are essential and you need to grow them in large quantities. Once we get them, then everything else will be in place and we can begin to translate this into clinical practice,” he said.

“What is required is the identification of adult sources of human epithelial and mesenchymal cells that can be obtained in sufficient numbers to make biotooth formation a viable alternative to dental implants,” Professor Sharpe added.

The hybrid bio-teeth were grown in the kidneys of laboratory mice to demonstrate that they can develop normally. They look much like ordinary teeth, with good roots and periodontal ligaments, Professor Sharpe said.

“The primary objective is to make a root with good periodontal ligaments. The rest of the tooth is really irrelevant as that can be dealt with by crowns,” he said.