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Dental caries, also known as tooth decay, cavities, or caries, is a breakdown of teeth due to activities of bacteria. The cavities may be a number of different colors from yellow to black. Symptoms may include pain and difficulty with eating.〔〔 Complications may include inflammation of the tissue around the tooth, tooth loss, and infection or abscess formation.〔〔 The cause of caries is bacterial break down of the hard tissues of the teeth (enamel, dentin and cementum). This occurs due to acid made from food debris or sugar on the tooth surface. Simple sugars in food are these bacteria's primary energy source and thus a diet high in simple sugar is a risk factor. If mineral breakdown is greater than build up from sources such as saliva, caries results. Risk factors include conditions that result in less saliva such as: diabetes mellitus, Sjogren's syndrome and some medications. Medications that decrease saliva production include antihistamines and antidepressants among others. Caries is also associated with poverty, poor cleaning of the mouth, and receding gums resulting in exposure of the roots of the teeth.〔 Prevention includes: regular cleaning of the teeth, a diet low in sugar, and small amounts of fluoride.〔〔 Brushing the teeth two times per day and flossing between the teeth once a day is recommended by many.〔〔 Fluoride may be from water, salt or toothpaste among other sources.〔 Treating a mother's dental caries may decrease the risk in her children by decreasing the numbers of certain bacteria.〔 Screening can result in earlier detection.〔 Depending on the extent of destruction, various treatments can be used to restore the tooth to proper function or the tooth may be removed.〔 There is no known method to grow back large amounts of tooth. The availability of treatment is often poor in the developing world.〔 Paracetamol (acetaminophen) or ibuprofen may be taken for pain.〔 Worldwide, approximately 2.43 billion people (36% of the population) have dental caries in their permanent teeth. The World Health Organizations estimates that nearly all adults have dental caries at some point in time. In baby teeth it affects about 620 million people or 9% of the population.〔 They have become more common in both children and adults in recent years. The disease is most common in the developed world and less common in the developing world due to greater simple sugar consumption.〔 Caries is Latin for "rottenness". ==Signs and symptoms== A person experiencing caries may not be aware of the disease.〔(Health Promotion Board: Dental Caries ), affiliated with the Singapore government. Page accessed August 14, 2006.〕 The earliest sign of a new carious lesion is the appearance of a chalky white spot on the surface of the tooth, indicating an area of demineralization of enamel. This is referred to as a white spot lesion, an incipient carious lesion or a "microcavity". As the lesion continues to demineralize, it can turn brown but will eventually turn into a cavitation ("cavity"). Before the cavity forms, the process is reversible, but once a cavity forms, the lost tooth structure cannot be regenerated. A lesion that appears dark brown and shiny suggests dental caries were once present but the demineralization process has stopped, leaving a stain. Active decay is lighter in color and dull in appearance.〔Johnson, Clarke. "(Biology of the Human Dentition )." Page accessed July 18, 2007.〕 As the enamel and dentin are destroyed, the cavity becomes more noticeable. The affected areas of the tooth change color and become soft to the touch. Once the decay passes through enamel, the dentinal tubules, which have passages to the nerve of the tooth, become exposed, resulting in pain that can be transient, temporarily worsening with exposure to heat, cold, or sweet foods and drinks. A tooth weakened by extensive internal decay can sometimes suddenly fracture under normal chewing forces. When the decay has progressed enough to allow the bacteria to overwhelm the pulp tissue in the center of the tooth a toothache can result and the pain will become more constant. Death of the pulp tissue and infection are common consequences. The tooth will no longer be sensitive to hot or cold, but can be very tender to pressure. Dental caries can also cause bad breath and foul tastes.〔(Tooth Decay ), hosted on the New York University Medical Center website. Page accessed August 14, 2006.〕 In highly progressed cases, infection can spread from the tooth to the surrounding soft tissues. Complications such as cavernous sinus thrombosis and Ludwig angina can be life-threatening.〔(Cavernous Sinus Thrombosis ), hosted on WebMD. Page accessed May 25, 2008.〕〔Hartmann, Richard W. (Ludwig's Angina in Children ), hosted on the American Academy of Family Physicians website. Page accessed May 25, 2008.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「dental caries」の詳細全文を読む スポンサード リンク
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