People want to change expensive rings as a sign of commitment in their relationship.

But what if the rings are made from their own bones?

No, I'm not talking about a bizarre rite.

And people can exchange jewelry made from bones grown in the laboratory using their bone cells.

Bone cells are put from wisdom teeth and then grown on a "scaffold" material in the lab.

The efforts are part of a collaboration between scientists and artists aiming to learn how to craft complex shapes from bone tissue.

Harriet Harriss and Matt Harrison, one of five couples involved in the project, have just been presented with their rings made from their bone cells.

"It's intriguing to have my own bone, my own matter objectified in this way and made into something precious and symbolic," said the possessor of a self-bone ring.

"When you think about it for a while, it's like ivory but more ethical, and the material has never been part of Harriet, just grown from her code taken from her body." said her partner.

"Yes it's the reason why people are interested and why they have the 'yuck' factor but when you see the object and think about it, I don't think it is gross at all. It's quite clean and pure."

The scientists used a bone sliver from wisdom teeth that attaches them to the jawbone.

The bone mineral was dissolved to extract the bone cells.

They are fed and grown on a "scaffold" material called bioglass, a special bioactive ceramic which mimics the structure of bone material.

Taking a biopsy from the volunteers was considered unethical and risky.

The technique could be also used to grow large bits of bone for people with cancer or who need bone replacements.

"This will improve the welfare of the patient as you won't need to harvest bone from elsewhere in the body," explained Dr Ian Thompson, a research fellow in oral and maxillofacial surgery at King's College.

"So if you have damaged a part of your jaw, you won't need to take a piece of the rib or somewhere else in the body to replace that bit of damaged bone we would simply grow that new piece in the laboratory and then implant it."

Thompson thinks it will not happen during his lifetime.