Birch bark tar has antiseptic properties, scientists say

Sarah Pickin, 23, found the lump of birch bark tar while on a dig in western Finland.

Neolithic people used the material as an antiseptic to treat gum infections, as well as a glue for repairing pots.

Ms Pickin's tutor, Professor Trevor Brown, said: "It's particularly significant because well-defined tooth imprints were found on the gum."

He explained: "Birch bark tar contains phenols, which are antiseptic compounds."

Ms Pickin, who was one of five UK students on a volunteer programme at the Kierikki Centre on the west coast of Finland, said: "I was delighted to find the gum and was very excited to learn more about the history."

She added: "I am keen to work in this area in the future so the experience has stood me in good stead."

The archaeology student also found part of an amber ring and a slate arrow head which will be on display at the centre following laboratory analysis.

While Neolithic people chewed gum to treat infection, a spokesman for the British Dental Association said chewing sugar free gum after meals stimulates saliva which offers protection against tooth decay.