Over half the world's population - 3.9 billion people - are suffering from untreated dental problems, according to a new report.

A team of international researchers investigated the area of oral health as part of the Global Burden of Disease (GBD) 2010 study.

They found that almost four billion people are affected by oral conditions, with untreated tooth decay and dental cavities (caries) being the most common of almost 300 diseases assessed. These two conditions alone affect some 35% of the world's population.

"There are close to four billion people in the world who suffer from untreated oral health conditions that cause toothache and prevent them from eating and possibly sleeping properly, which is a disability.

"This total does not even include small cavities or mild gum diseases, so we are facing serious problems in the population's oral health," explained lead researcher, Prof Wagner Marcenes, of the Institute of Dentistry at Queen Mary, University of London.

The report revealed that the global burden of oral conditions is moving away from severe tooth loss and towards severe periodontitis (gum disease) and untreated cavities.

"Tooth loss is often the final result when preventive or conservative treatments for tooth decay or gum disease fail or are unavailable. It is likely that current dental services are coping better to prevent tooth loss than in the past, but major efforts are needed to prevent the occurrence and development of gum diseases and tooth decay. Ironically the longer a person keeps their teeth the greater the pressure on services to treat them," Prof Marcenes said.

He added that the findings show that an urgent and organised response to oral health problems is urgently needed.

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