tooth decay tooth decay tooth decay, also known as cavities or caries, is the breakdown of teeth due to acids produced by 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. for caries of bone, see osteolysis. tooth decayother namesdental cavities, dental caries, cavities, cariesdestruction of a tooth by dental caries and disease.pronunciationcaries /ˈkɛəriːz/ specialtydentistrysymptomspain, tooth loss, difficulty eatingcomplicationsinflammation around the tooth, tooth loss, infection or abscess formationdurationlong termcausesbacteria producing acid from food debrisrisk factorsdiet high in simple sugar, diabetes mellitus, sjögren syndrome, medications that decrease salivapreventionlow-sugar diet, tooth brushing, fluoride, flossingmedicationparacetamol (acetaminophen), ibuprofenfrequency3.6 billion (2016) the cause of cavities is acid from bacteria dissolving the hard tissues of the teeth (enamel, dentin and cementum). the acid is produced by the bacteria when they break down 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, sjögren syndrome and some medications. medications that decrease saliva production include antihistamines and antidepressants. dental caries are also associated with poverty, poor cleaning of the mouth, and receding gums resulting in exposure of the roots of the teeth. prevention of dental caries includes regular cleaning of the teeth, a diet low in sugar, and small amounts of fluoride. brushing one's teeth twice per day and flossing between the teeth once a day is recommended. fluoride may be acquired from water, salt or toothpaste among other sources. treating a mother's dental caries may decrease the risk in her children by decreasing the number of certain bacteria she may spread to them. 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 3.6 billion people (48% of the population) have dental caries in their permanent teeth as of 2016. the world health organization 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 due to greater simple sugar consumption and less common in the developing world. caries is latin for "rottenness". signs and symptoms (a) a small spot of decay visible on the surface of a tooth. (b) the radiograph reveals an extensive region of demineralization within the dentin (arrows). (c) a hole is discovered on the side of the tooth at the beginning of decay removal. (d) all decay removed; ready for a filling. a person experiencing caries may not be aware of the disease. 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 "micro-cavity". 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. 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 the 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. in highly progressed cases, an infection can spread from the tooth to the surrounding soft tissues. complications such as cavernous sinus thrombosis and ludwig angina can be life-threatening. cause diagrammatic representation of acidogenic theory of causation of dental caries. four factors, namely, a suitable carbohydrate substrate (1), micro-organisms in dental plaque (2), a susceptible tooth surface (3) and time (4); must be present together for dental caries to occur (5). saliva (6) and fluoride (7) are modifying factors. four things are required for caries to form: a tooth surface (enamel or dentin), caries-causing bacteria, fermentable carbohydrates (such as sucrose), and time. this involves adherence of food to the teeth and acid creation by the bacteria that makes up the dental plaque. however, these four criteria are not always enough to cause the disease and a sheltered environment promoting development of a cariogenic biofilm is required. the caries disease process does not have an inevitable outcome, and different individuals will be susceptible to different degrees depending on the shape of their teeth, oral hygiene habits, and the buffering capacity of their saliva. dental caries can occur on any surface of a tooth that is exposed to the oral cavity, but not the structures that are retained within the bone. tooth decay is caused by biofilm (dental plaque) lying on the teeth and maturing to become cariogenic (causing decay). certain bacteria in the biofilm produce acid in the presence of fermentable carbohydrates such as sucrose, fructose, and glucose. caries occur more often in people from the lower end of the socio-economic scale than people from the upper end of the socio-economic scale, due to lack of education about dental care, and lack of access to professional dental care which may be expensive. bacteria a gram stain image of streptococcus mutans.