TITLE=SCIENCE IN THE NEWS #2113 - (1)Dental Health
This is Sarah Long.
And this is Bob Doughty with Science in the News, a VOA Special English program about recent developments in science. Today, we tell about diseases of the teeth and (2)gums, and ways to prevent and treat them.
People have been troubled by tooth and gum problems for thousands of years. The earliest record of dental (3)treatment comes from ancient Egypt. Books say the Egyptians treated gum swelling by using a (4)substance made of spices and onions. The earliest known person to treat tooth problems was also from Egypt. He lived about five-thousand years ago. He was known as a "doctor of the tooth".
(5)Experts say Chinese people living almost five-thousand years ago treated tooth pain by (6)acupuncture -- placing small sharp needles in different parts of the body. About one-thousand-three-hundred years ago, the Chinese filled holes in the teeth with a (7)mixture of the metals (8)mercury, (9)silver and tin. That was almost one-thousand years before a similar (10)substance was first used in western countries. Some ancient people like the Maya did not treat dental disease. But they made their teeth pretty by placing pieces of stone and metal on them.
The ancient Romans were careful about keeping their teeth clean. More than two-thousand years ago, the Romans treated toothaches, filled holes in teeth, and made (11)false teeth to replace those that had been lost.
From the fifth to the fifteenth centuries, Europeans with tooth problems went to people called barber-surgeons. These people performed many services, including cutting hair, pulling teeth and treating medical conditions. Dental treatment improved during the fourteenth and fifteenth centuries as doctors increased their knowledge about teeth.
Modern dentistry began in the Seventeen-Hundreds in France. That was when Pierre Fauchard published his book, "The (12)Surgeon Dentist." It was the first book about dental science. The book provided information about dental problems for other dentists to use. And it (13)described ways to keep teeth healthy. Pierre Fauchard is considered the father of (14)modern dentistry. His work was important in helping establish dentistry as a separate (15)profession.
Organized dentistry began in Eighteen-Forty. That is when the world's first dental school opened in the American city of Baltimore, Maryland. Four years later, a dentist first used drugs to stop the pain during dental work. Two years after that, another dentist(16) publicly (17)demonstrated the use of the gas, ether, as a way to reduce pain.
And in Eighteen-Fifty-Eight, another American dentist (18)invented a dental (19)drill that was powered by stepping on a device. This machine made it possible for dentists to use both hands when working in a patient's mouth.
In Eighteen-Ninety, an American scientist showed that bacteria in the mouth act on (20)sugars that remain on the teeth after eating. This action creates acid that (21)damages the tooth. The damage appears as a hole in the tooth. It is called a cavity. The part of the tooth that has been destroyed by the acid is inside the cavity. It is known as tooth (22)decay.
Tooth decay is (23)common in the United States and around the world. Dental professionals say the acid remaining in the mouth must be removed before it destroys the outer covering of the teeth. Dentists say the best thing people can do for their teeth is to keep them clean. After eating, people should use a (24)toothbrush or other device to clean the teeth. Then they should use a thin string or dental floss to remove particles of food between the teeth. Visiting a dentist every six months can help keep the teeth healthy, and prevent (25)cavities.
Experts say the greatest improvement in dental health during the twentieth century began in the United States in the early Nineteen-Hundreds. Dentists in the small western town of Colorado Springs, (26)Colorado found that children there had low rates of tooth decay. They discovered that the town's water supply contained (27)fluoride, an (28)element found in rocks and minerals. Public health researchers thought that adding fluoride to water in other American cities could reduce the rates of tooth decay.
In Nineteen-Forty-Five, a test program began in the middle western state of Michigan. Ten years later, results showed a fifty to seventy percent (29)reduction in cavities in the children who drank water containing fluoride. Since then, many studies have confirmed the value of fluoride. Today, most of the American water supply contains fluoride. And international health organizations, including the World Health Organization, support water fluoridation programs.
Decay is not the only disease that can cause tooth loss. Another serious disease affects the gums, the (30)tissue that surrounds the teeth. It is also caused by (31)bacteria. If the bacteria are not removed every day, they form a substance that stays on the teeth. This substance is known as (32)plaque.
At first, the gums appear to be swollen, and may bleed when the teeth are brushed. This can lead to serious infection of the tissue around the teeth. The infection may damage the bone that supports the teeth and cause tooth loss and other health problems. Studies have found that people with severe gum disease have an increased risk of developing heart disease, diabetes and stroke.
Gum disease can be treated by a special dentist called a periodontist. Periodontists are trained to repair the gum areas that have been damaged. This can be painful and costly.
Dental health experts say the best thing to do is to stop gum disease before it starts. The way to do this is to clean the teeth every day. People also should use dental floss to remove plaque from between the teeth. Most experts also agree that another way to prevent tooth and gum problems is to eat foods high in calcium and (33)vitamins and low in sugar.
Scientists continue to develop better dental treatments and equipment. Improved (34)technology may change the way people receive dental treatment in the future. For example, dentists are now using laser light to treat diseased gums and teeth. Dentists use computer technology to help them repair damaged teeth. Researchers have developed improved methods to repair bone that supports the teeth. And genetic research is expected to develop tests that will show the (35)presence of disease-causing bacteria in the mouth.
Such increased knowledge about dental diseases and ways to prevent them has improved the health of many people. Yet problems remain in some areas. In (36)industrial countries, minorities and other groups have a high level of untreated dental disease. In developing countries, many areas do not have even emergency care services. The World Health Organization says people in countries in Africa have the most tooth and gum problems.
World Health organization experts say the dental health situation is different for almost every country in the world. As a result, it has developed oral health programs separately for each area.
The W-H-O oral health program is mainly for people living in poor areas. It provides them with information about mouth diseases and health care. It also studies (37)preventive programs using fluoride in water, salt, milk and (38)toothpaste. And it explores ways to include dental health in national health care systems.
Many governments and other organizations provide help so people can get needed dental health services. But dental health professionals say people should take good care of their teeth and gums. They say people should keep their teeth as clean as possible. They should eat foods high in calcium and fiber. These include milk products, whole grain breads and cereals, vegetables, fruits, beans and nuts. Recent studies have shown that eating nuts can help slow the production of plaque on the teeth. Experts say these activities will help everyone improve their dental health throughout their lives.
This SCIENCE IN THE NEWS program was written and produced by Nancy Steinbach. This is Bob Doughty.
And this is Sarah Long. Join us again next week for more news about science.
(1) dental[ 5dentl ]adj.牙齿的
(2) gum[ ^Qm ]n.齿龈, 树脂, 橡胶, 橡胶树, 口香糖, 香口胶, 泡泡糖
(3) treatment[ 5tri:tmEnt ]n.待遇, 对待, 处理, 治疗
(4) substance[ 5sQbstEns ]n.物质, 实质, 主旨
(5) expert[ 5ekspE:t ]n.专家, 行家, [军](特等)射手adj.老练的, 内行的, 专门的
(7) mixture[ 5mikstFE ]n.混合, 混合物, 混合剂
(8) mercury[ 5mE:kjuri ]n.水银, 汞, [罗神]墨丘利神(众神的信使)
(9) silver[ 5silvE ]n.银, 银子vt.镀银
(10) substance[ 5sQbstEns ]n.物质, 实质, 主旨
(11) false[ fC:ls ]adj.错误的, 虚伪的, 假的, 无信义的, 伪造的, 人工的, 不老实的adv.欺诈地
(12) surgeon[ 5sE:dVEn ]n.外科医生
(13) describe[ dis5kraib ]vt.描写, 记述, 形容, 形容v.描述
(14) modern[ 5mCdEn ]n.现代人, 有思想的人adj.近代的, 现代的, 现代化的, 时髦的
(15) profession[ prE5feFEn ]n.职业, 专业, 表白, 宣布
(16) publicly[5pQblIklI]adv.公然地, 舆论上
(17) demonstrate[ 5demEnstreit ]vt.示范, 证明, 论证vi.示威
(18) invent[ in5vent ]vt.发明, 创造v.发明
(19) sugar[ 5Fu^E ]n.糖, 食糖
(20) drill[ dril ]n.钻孔机, 钻子, 播种机, 军事训练, 操练, (反复)练习, v.训练, 钻孔, 条播
(21) damage[ 5dAmidV ]n.损害, 伤害v.招致损害n.[律] (用复数)赔偿金
(22) decay[ di5kei ]vi.腐朽, 腐烂, 衰减, 衰退n.腐朽, 腐烂, 衰减, 衰退v.衰落
(23) common[ 5kCmEn ]adj.共同的, 公共的, 公有的, 普通的, n.[复][总]平民, 公有, 普通,
(25) cavity[ 5kAviti ]n.洞, 空穴, [解剖]腔
(26) Colorado[ 7kClE5rB:dEu ]美国科罗拉多州(位于美国西部)
(27) fluoride[ 5flu(:)Eraid ]n.氟化物
(28) element[ 5elimEnt ]n.要素, 元素, 成分, 元件, 自然环境
(29) reduction[ ri5dQkFEn ]n.减少, 缩影, 变形, 缩减量, 约简
(30) tissue[ 5tisju: ]n.薄的纱织品, 薄纸, 棉纸, [生]组织, 连篇
(31) bacteria[ bAk5tiEriE ]n.细菌
(32) plaque[ plB:k ]n.装在墙上作装饰或纪念用的薄金属板或瓷片
(33) vitamin[ 5vaitEmin, 5vi- ]n.维他命, 维生素
(34) technology[ tek5nClEdVi ]n.工艺, 科技, 技术
(35) presence[ 5prezns ]n.出席, 到场, 存在
(36) industrial[ in5dQstriEl ]adj.工业的, 产业的, 实业的, 从事工业的n.工业工人
(37) preventive[ pri5ventiv ]adj.预防性的