question: If "our saliva breaks down fat and carbs", why isn't saliva and flushing with water enough to keep our teeth clean and healthy?
comment: It doesn't break it down as much as it makes it easier to swallow. The enzymes coupled with mechanical force work quite well. Saliva does help keep bacteria in check, but some find ways to survive. We get tooth decay from the acids these bacteria produce and our saliva can't neutralize those.
passages: The main function of saliva is to flush out all of the micro-organisms that could potentially threaten our health. The flow of saliva constantly bathes the mouth and detaches all micro-organisms that are not already firmly attached to a surface. This makes it difficult for bacteria to adhere to surfaces to even begin to form biofilms. Many harmful micro-organisms, therefore, are unable to attach quick enough to a surface before they are caught in saliva and swallowed. Although saliva does a lot to keep our bodies healthy, it cannot completely keep all bacteria from adhering to tooth, tongue or gum surfaces.
   Saliva can prevent microbial growth based on the elements it contains. For example, lactoferrin in saliva binds naturally with iron. Since iron is a major component of bacterial cell walls, removal of iron breaks down the cell wall, which in turn breaks down the bacteria. Antimicrobial peptides such as histatins inhibit the growth of Candida albicans and Streptococcus mutans. Salivary Immunoglobulin A serves to aggregate oral bacteria such as S. mutans and prevent the formation of dental plaque.
  
  BULLET::::- Tissue repair
  
  Saliva can encourage soft tissue repair by decreasing clotting time and increasing wound contraction.
  
  BULLET::::- Digestion
   Saliva consists of proteins (for example; mucins) that lubricate and protect both the soft and hard tissues of the oral cavity. Mucins are the principal organic constituents of mucus, the slimy visco-elastic material that coats all mucosal surfaces.
  
  BULLET::::- Buffering
  
  In general, the higher the saliva flow rate, the faster the clearance and the higher the buffer capacity, hence better protection from dental caries. Therefore, people with a slower rate of saliva secretion, combined with a low buffer capacity, have lessened salivary protection against microbes.
  
  BULLET::::- Pellicle formation
   The sugar concentration in salivary secretions can vary. Blood sugar levels are reflected in salivary gland secretions. High salivary glucose (HSG) levels are a glucose concentration ≥ 1.0 mg/d, n = 175) and those with low salivary glucose (LSG) levels are  0.1 mg/dL n = 2,537). Salivary gland secretions containing high levels of sugar change the oral microbiome and contributes to an environment that is conductive to the formation of dental caries and gingivitis.
  
  Section::::Salivary glands.
   Saliva contributes to the digestion of food and to the maintenance of oral hygiene. Without normal salivary function the frequency of dental caries, gum disease (gingivitis and periodontitis), and other oral problems increases significantly.
  
  Section::::Functions.:Lubricant.
  
  Saliva coats the oral mucosa mechanically protecting it from trauma during eating, swallowing, and speaking. Mouth soreness is very common in people with reduced saliva (xerostomia) and food (especially dry food) sticks to the inside of the mouth.
  
  Section::::Functions.:Digestion.
   The function of the salivary glands is to secrete saliva, which has a lubricating function, which protects the oral mucosa of the mouth during eating and speaking. Saliva also contains digestive enzymes (e.g. salivary amylase) and has antimicrobial action and acts as a buffer. Persons with reduced salivary flow or hyposalivation often suffer from dry mouth or xerostomia, which can result in severe dental caries (tooth decay) as a result of the loss of the protective effects of saliva.
   As well as its role in supplying digestive enzymes, saliva has a cleansing action for the teeth and mouth. It also has an immunological role in supplying antibodies to the system, such as immunoglobulin A. This is seen to be key in preventing infections of the salivary glands, importantly that of parotitis.
   Reduced salivary flow rate is associated with increased caries since the buffering capability of saliva is not present to counterbalance the acidic environment created by certain foods. As a result, medical conditions that reduce the amount of saliva produced by salivary glands, in particular the submandibular gland and parotid gland, are likely to lead to dry mouth and thus to widespread tooth decay. Examples include Sjögren's syndrome, diabetes mellitus, diabetes insipidus, and sarcoidosis. Medications, such as antihistamines and antidepressants, can also impair salivary flow. Stimulants, most notoriously methylamphetamine, also occlude the flow of saliva to an extreme degree. This is known as meth mouth. Tetrahydrocannabinol (THC), the active chemical substance in cannabis, also causes a nearly complete occlusion of salivation, known in colloquial terms as "cotton mouth". Moreover, 63% of the most commonly prescribed medications in the United States list dry mouth as a known side-effect. Radiation therapy of the head and neck may also damage the cells in salivary glands, somewhat increasing the likelihood of caries formation.
   Sialogogues can be used in the treatment of xerostomia (the subjective feeling of having a dry mouth), to stimulate any functioning salivary gland tissue to produce more saliva. Saliva has a bactericidal effect, so when low levels of it are secreted, the risk of caries increases. Not only this, but fungal infections such as oral candidosis also can be a consequence of low salivary flow rates. The buffer effect of saliva is also important, neutralising acids that cause tooth enamel demineralisation. The following are used in dentistry to treat xerostomia:
   Saliva function can be organised into five major categories that serve to maintain oral health and create an appropriate ecologic balance:
  
  BULLET::::- Lubrication and protection
  
  BULLET::::- Buffering action and clearance
  
  BULLET::::- Maintenance of tooth integrity
  
  BULLET::::- Antibacterial activity
  
  BULLET::::- Taste and digestion.
   Nonetheless, licking does play a role for humans. Even though humans cannot effectively drink water by licking, the human tongue is quite sufficient for licking more viscous fluids. Some foods are sold in a form intended to be consumed mainly by licking, e.g. ice cream cones and lollipops.
  
  Some people in the Afar tribe of Ethiopia have been reported to have used their tongues to lick other humans, as a way of cleaning them from the dust that accumulates on them in a very water-scarce region.
   Diet has an influence in our oral health as well. Most of us have been warned against eating too much candy because it will give us cavities. This is true because much of the bacteria in our mouths are nourished by simple sugars and carbohydrates. An excess of candy, soda, or other simple sugars is an easy way to let bacteria thrive in our mouths. In addition, there are other ways to further reduce the risk of invaders harming the mouths’ health. Visits to the dentist can be beneficial where fluoride treatments are available. Combined with dental sealants, these treatments can, in most cases, ensure prevention of harmful bacterial effects. Fluoride is extremely effective in protecting enamel on the teeth. “Fluoride, a chemical that appears naturally in groundwater in many areas of the world, quickly bonds with the tooth's enamel to maintain its smooth crystalline surface and deter bacteria from gaining a toehold.” The Oral-B website advises people to “drink tap water when possible” because “if bottled water is your main source of drinking water, you could be missing the decay-preventative benefits of fluoride.” Also, a study in the Journal of the American Dental Association states that “antiseptic mouthwashes have been associated with a 28 to 34 percent reduction in dental plaque biofilms at six month follow-ups. Chlorhexidine gluconate [mouthwash] rinses, when combined with toothbrushing, have been reported to reduce oral biofilms . . . by 50 to 55 percent.” By going to the dentist and following advice, one can begin to prevent oral infection and disease.
   The environment present in the human mouth allows the growth of characteristic microorganisms found there. It provides a source of water and nutrients, as well as a moderate temperature. Resident microbes of the mouth adhere to the teeth and gums to resist mechanical flushing from the mouth to stomach where acid-sensitive microbes are destroyed by hydrochloric acid.
   Certain bacteria in the mouth live off the remains of foods, especially sugars and starches. In the absence of oxygen they produce lactic acid, which dissolves the calcium and phosphorus in the enamel. This process, known as "demineralisation", leads to tooth destruction. Saliva gradually neutralises the acids which cause the pH of the tooth surface to rise above the critical pH, typically considered to be 5.5. This causes 'remineralisation', the return of the dissolved minerals to the enamel. If there is sufficient time between the intake of foods then the impact is limited and the teeth can repair themselves. Saliva is unable to penetrate through plaque, however, to neutralize the acid produced by the bacteria.
   In equilibrium, the bacterial biofilm produced by the fermentation of sugar in the mouth is quickly swept away by the saliva, except for dental plaque. In cases of imbalance in the equilibrium, oral microorganisms grow out of control and cause oral diseases such as tooth decay and periodontal disease. Several studies have also linked poor oral hygiene to infection by pathogenic bacteria.
  
  Section::::Role in Health.
   Saliva keeps the ecosystem of the mouth in balance. It contains its own bacterial enzymes that are beneficial to our health. An example of these are lysozomes. These antibacterial agents in saliva kill bacteria in our mouths and protect from potentially dangerous diseases. In addition, saliva contains phosphate and calcium ions that help repair microscopic chinks made in the teeth by the bacteria's acid. The major organic constituents of saliva are proteins and glycoproteins. Proteins in saliva float around and influence the mouth's ecosystem in multiple ways. Some of the proteins provide nutrients for bacteria, while others cause bacteria to clump together so they are unable to stick to any surface and are washed away.
   BULLET::::- Dental caries (xerostomia related caries) – Without the anticariogenic actions of saliva, tooth decay is a common feature and may progress much more aggressively than it would otherwise ("rampant caries"). It may affect tooth surfaces that are normally spared, e.g., cervical caries and root surface caries. This is often seen in patients who have had radiotherapy involving the major salivary glands, termed radiation-induced caries. Therefore, it is important that any products used in managing dry mouth symptoms are sugar-free, as the presence of sugars in the mouth support the growth of oral bacteria, resulting in acid production and development of dental caries.
   Because of the amount of bacteria in each person's mouth, there is a transfer of bacteria through saliva when lip balm, drinks, toothbrushes, or anything else is shared. Some of these viruses that result are relatively inconsequential while others could potentially have a serious impact on one's life. Some examples of the milder diseases passed through saliva include herpes simple virus (cold sores or canker sores), flu virus, cold virus, and various bacteria that cause periodontal disease (inflammation or infection of gum tissue), venereal diseases, and candida albicans (fungus).
   Section::::References.
  
  BULLET::::- "Antony van Leeuwenhoek." University of California Museum of Paleontology. 10 Oct. 2008
  
  BULLET::::- "Avoiding Tooth Decay." "Oral-B". 10 Oct. 2008 .
  
  BULLET::::- DePaola, Dominick P., Frederick A. Curro, and Domenick T. Zero. "Saliva: The Precious Body Fluid." "J Am Dent Assoc" 139.suppl_2 (2008): 5S-10. 10 Oct 2008.
  
  BULLET::::- Dreher, Nancy. "What you need to know about mono." "Current Health" 2 23.7 (Mar. 1997): 28. Academic Search Premier. EBSCO. Brigham Young University, Provo, UT. 10 Oct. 2008.
  
  BULLET::::- Favot, Christa. "What is Living in my Mouth? Biofilms, Carbohydrate, and Acid Blasts." "The Naked Scientists" (Mar. 2006). 10 Oct. 2008.
   Section::::Diseases.
  
  Section::::Diseases.:Diseases transmitted through saliva.
  
  Each day numerous bacteria grow in a person's mouth. Though bacteria and saliva can be beneficial to one's health, both can also cause problems. Many diseases are related to oral bacteria. Proper oral care and habits can protect against and reduce the effects of some harmful bacteria.
   The enzymes found in saliva are essential in beginning the process of digestion of dietary starches and fats. These enzymes also play a role in breaking down food particles entrapped within dental crevices, thus protecting teeth from bacterial decay. Saliva also performs a lubricating function, wetting food and permitting the initiation of swallowing, and protecting the oral mucosa from drying out.
  
  Various animal species have special uses for saliva that go beyond predigestion. Some swifts use their gummy saliva to build nests. "Aerodramus" nests form the basis of bird's nest soup.
   The 2003 WHO report stated that "Sugars are undoubtedly the most important dietary factor in the development of dental caries". A review of human studies showed that the incidence of caries is lower when sugar intake is less than 10% of total energy consumed.
  
  Section::::Health effects.:Nutritional displacement.
   Oral bacteria work with our immune system to keep our bodies disease free by fighting disease-producing germs that try to come in through the mouth. For example, some of these bacteria produce organic acids that kill the organisms that cause intestinal problems. Without these good bacteria, our immune systems would be constantly bombarded by airborne and saliva-transferred germs. Bacteria are also needed to control the growth of fungus. “Balance between all the different bacteria and fungus are critical” or else the “fungus overgrows and takes over.” So, ironically, though bacteria have the potential to harm us, our mouth and the good bacteria in it are the body's first line of defense. These bacteria are transmitted to a human early in their childhood through their contact with their caretakers by kisses or food premastication.
   The most commonly recognised bacteria that are responsible for initiating the biofilm formation that can eventually lead to caries are streptococcus mutans and lactobacillus. The key factors for virulence include their ability to metabolise glucose and similar sugars, their tolerance for a low pH environment and their acidogenicity. The presence of streptococci encourage adherence of more cariogenic bacteria, which in turn increases the likelihood for caries. Although factors such as the quality of saliva, using fluoridated toothpaste and chewing gum after meals can inhibit the growth of these bacteria and change the biofilm environment. Saliva containing more buffering agents such as calcium and phosphate ions alter the internal environment of dental plaque to become less acidic, favouring the growth of less cariogenic organisms. The fluoride components of fluoridated toothpaste can be bacteriostatic to cariogenic bacteria, decreasing their acidogenicity and proliferation. Chewing gum can disturb the mature and fairly stable acid producing plaque to alter the bacterial composition of the biofilm. In turn the disease causing organisms may still be present, but are so in reduced numbers. Chewing gum containing sufficient levels of xylitol also has the ability to reduce the number of streptococcus mutans present in the saliva as well as the mechanisms for the bacteria to adhere to tooth tissue, which reduces the chance for reinfection.
   Frequency of sugar sweetened beverages results in dental caries, which are caused by Streptococcus bacteria. Dental caries is an infectious oral disease and is the breakdown of the teeth due to the bacteria in the mouth. It occurs when bacteria within the plaque metabolize the sugar, releasing various acids as waste compounds. As the acids are released, they form holes in the teeth which dissolve the enamel. The sugars, therefore provide a passageway for the activities of the oral bacteria, lowering salivary pH. The bacteria alone are not the sole cause of tooth decay, as it is the presence of these sugars that inhibit the production of acid.
  
presuppositions: Saliva breaks down fat and carbs. Saliva can break down fat and carbs.
corrections: Saliva makes fat and carbs easier to swallow. Saliva doesn't break it down as much as it makes it easier to swallow.
raw_presuppositions: Saliva breaks down fat and carbs. Saliva can break down fat and carbs.
raw_corrections: Saliva makes fat and carbs easier to swallow. Saliva doesn't break it down as much as it makes it easier to swallow.