Some 2.4 billion people worldwide have untreated decay in their permanent teeth, while 621 million children have untreated decay in their milk teeth, a major new study has found.

It was carried out by the international Oral Health Research Group and is contained in the latest Global Burden of Disease (GBD) study.

It found that an estimated 190 million new cases of tooth decay in adults are expected to develop every year, and it noted that the 2.4 billion people currently with untreated delay in their permanent teeth represents 35% of the world's population.

Not surprisingly, the researchers found that the problem of tooth decay is a neglected one, even in high income countries.

They carried out a detailed analysis of all data on untreated decay between 1990 and 2010. A total of 192 studies involving 1.5 million children aged between one and 14 in 74 countries, and 186 studies involving 3.2 million people aged five and older in 67 countries, were assessed.

"Our report is a startling reminder of the vital need to develop effective oral health promotion strategies. It is alarming to see prevention and treatment of tooth decay has been neglected at this level because if left untreated it can cause severe pain, mouth infection and it can negatively impact children's growth," commented the study's lead author, Prof Wagner Marcenes, of Queen Mary University of London.

He insisted that these findings should ‘serve as a wake-up call to policymakers to increase their focus on the importance of dental health'.

This is an issue that the Irish Dental Association has been highlighting here in recent years. Due to cuts in the medical card and PRSI dental schemes in recent years, certain treatments which were free or subsidised, such as fillings and extractions, are no longer available.

Dentists have repeatedly criticised these cuts, which they believe will be more costly in the long-run, as many people who choose to avoid the dentist due to the costs involved will end up with poorer oral health as a result.

Meanwhile, the study also highlighted the problem of dietary habits when it comes to dental health. Frequent snacking and the consumption of high amounts of sugary food and drinks are now more common than ever, but also greatly contribute to this problem.

Details of these findings are published in the Journal of Dental Research.