Erosion can make teeth more sensitive and potentially painful

They earn their owners billions of pounds each year and many have gone largely unchanged for decades.

But now some of the world's leading multinational companies are facing calls to tamper with the ingredients of some of their best-selling soft drinks.

Dentists say the changes are needed if they are to stop a tide of erosion that is damaging people's teeth.

Tooth erosion

They want soft drinks manufacturers to consider adding calcium or other agents to their drink to make them less harmful to teeth.

Many soft drinks have high levels of acidity. These can over time damage the protective layer around teeth. This can make the teeth more sensitive and potentially painful.

We are not going to stop people from drinking these soft drinks so we would very much support research to find safer formulations Liz Kay, British Dental Association

Researchers from the University of Iceland have suggested one way to get around this problem is to change the recipes of fizzy drinks.

Writing in the British Dental Journal, they urged the drinks industry to consider the move.

"Considering the increasing prevalence of tooth erosion, especially in young children and teenagers and the strong association between consumption of acidic drinks and tooth erosion, it still seems logical to continue the development of drinks with low erosive potential.

"Drink modification has considerable potential in combating erosion."

Liz Kay of the British Dental Association backed the proposals.

"Tooth erosion appears to be on the increase and soft drinks play a role in that.

"We are not going to stop people from drinking these soft drinks so we would very much support research to find safer formulations."

A spokeswoman for Coca Cola declined to comment on the proposals or reveal whether the company has considered reducing the acidity of its drinks.

But she added: "We are always looking at being responsive to consumer needs and product quality."

A spokesman for the British Soft Drinks Association said people could reduce their risks of tooth erosion by changing the way they consume fizzy drinks.

"To minimise the impact of soft drinks, people should consume them with meals. They should also drink using a straw and avoid playing with the drink in their mouth.

"We would also advise against drinking soft drinks during the night.