Fluoride beads inserted in the mouth could put an end to tooth sensitivity for millions of people, researchers at the University of Leeds claim.
The bead combats decay as well as sensitivity
About 15% of the adult population suffer from the pain which is often caused by receding gums, tooth decay, abrasion or teeth grinding.
The Leeds dental institute found the beads, when inserted into a bracket in the mouth, stopped tooth sensitivity.
A full-scale trial is now being carried out by the researchers.
Professor Jack Toumba and Dr Gayatri Kotru made the chance finding in 1999 when a volunteer was testing the effect of the beads on tooth decay.
During the study she found her teeth no longer felt sensitive, Dr Kotru said.
"The beads have a two in one affect. Although we were focusing on decay, in doing so we discovered that it has a positive effect on tooth sensitivity," she added.
It is thought the fluoride, which is fixed in brackets on the upper first molar on each side of the mouth, blocks the tiny fluid-filled tubes in dentine which are sensitive when exposed.
Prof Toumba added: "Desensitising toothpastes have only a temporary effect.
"The bead is replaced easily and painlessly every two years, giving constant freedom from tooth sensitivity."