From VOA Learning English, this is the Health Report.
A new report says nearly four-billion people have major tooth decay, or cavities. That number represents more than half of the world's population. Health officials are warning that failure to repair cavities can lead to social and emotional problems.
Wagner Marcenes is with the Institute of Dentistry at Queen Mary, University of London. He led a team of researchers as part of the Global Burden of Disease 2010 study. About 500 researchers attempt to collect and examine studies about all major diseases. They used the information to estimate rates of the infection.
The report says untreated tooth decay is the most common of all 291 major diseases and injuries. Professor Marcenes says cavities or holes in permanent teeth are also known as caries.
"Caries is a chronic disease that shares the same risk factors as cancer, cardiovascular disease. What we're having now is an increase in disease from highly developed countries happening in sub-Saharan Africa and probably it will be in other areas of Africa, too."
He says an increase in tooth decay in Africa could be a result of developing countries becoming more like Western nations.
"It is likely to be related to a change in diet. Our industrialized diet leads to chronic disease, which includes caries. And that may be the main explanation."
Western diets are rich in sugar, a leading cause of health problems in the mouth. In western countries, water supplies are treated with the chemical fluoride. Adding fluoride to the water makes teeth resistant to the bacteria that can cause tooth decay.
Wagner Marcenes says oral health problems can have a major effect on a person's quality of life. First, cavities make eating difficult. Second, people may change what they eat. They may eat softer foods that are not hard to chew. However, softer foods are often fattier foods.
But professor Marcenes says the biggest issue in tooth decay is both social and mental. He says the researchers found strong evidence that the mouth has a big influence on socialization. He says many people want to hide bad teeth. They smile less and communicate less.
Wagner Marcenes is calling for an "urgent, organized, social response" to the widespread lack of oral health. He believes in a natural method to fight tooth decay by having a healthier diet. He is also calling for the development of new and less costly dental materials and treatments.
And that's the Health Report, I'm Christopher Cruise.
1.cavity n. 腔；洞，凹处
Cavities in teeth are caused by decay.
2.caries n. [口腔] 龋齿；骨疡；骨溃疡
Fluoride can prevent dental caries and it has been applied since the 20th century.
3.cardiovascular adj. [解剖] 心血管的
The major emphasis of this review will be CO and its effects on the cardiovascular system.
4.fluoride n. 氟化物
Fluoride damage is generally restricted to areas near manufacturing plants.