Datasets:
hpprc
/
enwiki-paragraphs

Dataset card Data Studio Files Community
2
title
stringlengths
1
182
passage_id
int64
12
4.55M
section_title
stringlengths
0
402
text
stringlengths
0
99.6k
Algorithm
775
Classification
Some problems may have multiple algorithms of differing complexity, while other problems might have no algorithms or no known efficient algorithms. There are also mappings from some problems to other problems. Owing to this, it was found to be more suitable to classify the problems themselves instead of the algorithms into equivalence classes based on the complexity of the best possible algorithms for them.
Algorithm
775
Classification
The adjective "continuous" when applied to the word "algorithm" can mean:
Algorithm
775
Algorithm = Logic + Control
In logic programming, algorithms are viewed as having both "a logic component, which specifies the knowledge to be used in solving problems, and a control component, which determines the problem-solving strategies by means of which that knowledge is used."
Algorithm
775
Algorithm = Logic + Control
The Euclidean algorithm illustrates this view of an algorithm. Here is a logic programming representation, using :- to represent "if", and the relation gcd(A, B, C) to represent the function gcd(A, B) = C:
Algorithm
775
Algorithm = Logic + Control
In the logic programming language Ciao the gcd relation can be represented directly in functional notation:
Algorithm
775
Algorithm = Logic + Control
The Ciao implementation translates the functional notation into a relational representation in Prolog, extracting the embedded subtractions, A-B and B-A, as separate conditions:
Algorithm
775
Algorithm = Logic + Control
The resulting program has a purely logical (and "declarative") reading, as a recursive (or inductive) definition, which is independent of how the logic is used to solve problems:
Algorithm
775
Algorithm = Logic + Control
Different problem-solving strategies turn the logic into different algorithms. In theory, given a pair of integers A and B, forward (or "bottom-up") reasoning could be used to generate all instances of the gcd relation, terminating when the desired gcd of A and B is generated. Of course, forward reasoning is entirely useless in this case. But in other cases, such as the definition of the Fibonacci sequence and Datalog, forward reasoning can be an efficient problem solving strategy. (See for example the logic program for computing fibonacci numbers in Algorithm = Logic + Control).
Algorithm
775
Algorithm = Logic + Control
In contrast with the inefficiency of forward reasoning in this example, backward (or "top-down") reasoning using SLD resolution turns the logic into the Euclidean algorithm:
Algorithm
775
Algorithm = Logic + Control
One of the advantages of the logic programming representation of the algorithm is that its purely logical reading makes it easier to verify that the algorithm is correct relative to the standard non-recursive definition of gcd. Here is the standard definition written in Prolog:
Algorithm
775
Algorithm = Logic + Control
This definition, which is the specification of the Euclidean algorithm, is also executable in Prolog: Backward reasoning treats the specification as the brute-force algorithm that iterates through all of the integers C between 1 and A, checking whether C divides both A and B, and then for each such C iterates again through all of the integers D between 1 and A, until it finds a C such that C is greater than or equal to all of the D that also divide both A and B. Although this algorithm is hopelessly inefficient, it shows that formal specifications can often be written in logic programming form, and they can be executed by Prolog, to check that they correctly represent informal requirements.
Algorithm
775
Legal issues
Algorithms, by themselves, are not usually patentable. In the United States, a claim consisting solely of simple manipulations of abstract concepts, numbers, or signals does not constitute "processes" (USPTO 2006), so algorithms are not patentable (as in Gottschalk v. Benson). However practical applications of algorithms are sometimes patentable. For example, in Diamond v. Diehr, the application of a simple feedback algorithm to aid in the curing of synthetic rubber was deemed patentable. The patenting of software is controversial, and there are criticized patents involving algorithms, especially data compression algorithms, such as Unisys's LZW patent.
Algorithm
775
Legal issues
Additionally, some cryptographic algorithms have export restrictions (see export of cryptography).
Algorithm
775
History: Development of the notion of "algorithm"
The earliest evidence of algorithms is found in the Babylonian mathematics of ancient Mesopotamia (modern Iraq). A Sumerian clay tablet found in Shuruppak near Baghdad and dated to c. 2500 BC described the earliest division algorithm. During the Hammurabi dynasty c. 1800 – c. 1600 BC, Babylonian clay tablets described algorithms for computing formulas. Algorithms were also used in Babylonian astronomy. Babylonian clay tablets describe and employ algorithmic procedures to compute the time and place of significant astronomical events.
Algorithm
775
History: Development of the notion of "algorithm"
Algorithms for arithmetic are also found in ancient Egyptian mathematics, dating back to the Rhind Mathematical Papyrus c. 1550 BC. Algorithms were later used in ancient Hellenistic mathematics. Two examples are the Sieve of Eratosthenes, which was described in the Introduction to Arithmetic by Nicomachus, and the Euclidean algorithm, which was first described in Euclid's Elements (c. 300 BC).
Algorithm
775
History: Development of the notion of "algorithm"
Tally-marks: To keep track of their flocks, their sacks of grain and their money the ancients used tallying: accumulating stones or marks scratched on sticks or making discrete symbols in clay. Through the Babylonian and Egyptian use of marks and symbols, eventually Roman numerals and the abacus evolved (Dilson, p. 16–41). Tally marks appear prominently in unary numeral system arithmetic used in Turing machine and Post–Turing machine computations.
Algorithm
775
History: Development of the notion of "algorithm"
Muhammad ibn Mūsā al-Khwārizmī, a Persian mathematician, wrote the Al-jabr in the 9th century. The terms "algorism" and "algorithm" are derived from the name al-Khwārizmī, while the term "algebra" is derived from the book Al-jabr. In Europe, the word "algorithm" was originally used to refer to the sets of rules and techniques used by Al-Khwarizmi to solve algebraic equations, before later being generalized to refer to any set of rules or techniques. This eventually culminated in Leibniz's notion of the calculus ratiocinator (c. 1680):
Algorithm
775
History: Development of the notion of "algorithm"
A good century and a half ahead of his time, Leibniz proposed an algebra of logic, an algebra that would specify the rules for manipulating logical concepts in the manner that ordinary algebra specifies the rules for manipulating numbers.
Algorithm
775
History: Development of the notion of "algorithm"
The first cryptographic algorithm for deciphering encrypted code was developed by Al-Kindi, a 9th-century Arab mathematician, in A Manuscript On Deciphering Cryptographic Messages. He gave the first description of cryptanalysis by frequency analysis, the earliest codebreaking algorithm.
Algorithm
775
History: Development of the notion of "algorithm"
The clock: Bolter credits the invention of the weight-driven clock as "The key invention [of Europe in the Middle Ages]", in particular, the verge escapement that provides us with the tick and tock of a mechanical clock. "The accurate automatic machine" led immediately to "mechanical automata" beginning in the 13th century and finally to "computational machines"—the difference engine and analytical engines of Charles Babbage and Countess Ada Lovelace, mid-19th century. Lovelace is credited with the first creation of an algorithm intended for processing on a computer—Babbage's analytical engine, the first device considered a real Turing-complete computer instead of just a calculator—and is sometimes called "history's first programmer" as a result, though a full implementation of Babbage's second device would not be realized until decades after her lifetime.
Algorithm
775
History: Development of the notion of "algorithm"
Logical machines 1870 – Stanley Jevons' "logical abacus" and "logical machine": The technical problem was to reduce Boolean equations when presented in a form similar to what is now known as Karnaugh maps. Jevons (1880) describes first a simple "abacus" of "slips of wood furnished with pins, contrived so that any part or class of the [logical] combinations can be picked out mechanically ... More recently, however, I have reduced the system to a completely mechanical form, and have thus embodied the whole of the indirect process of inference in what may be called a Logical Machine" His machine came equipped with "certain moveable wooden rods" and "at the foot are 21 keys like those of a piano [etc.] ...". With this machine he could analyze a "syllogism or any other simple logical argument".
Algorithm
775
History: Development of the notion of "algorithm"
This machine he displayed in 1870 before the Fellows of the Royal Society. Another logician John Venn, however, in his 1881 Symbolic Logic, turned a jaundiced eye to this effort: "I have no high estimate myself of the interest or importance of what are sometimes called logical machines ... it does not seem to me that any contrivances at present known or likely to be discovered really deserve the name of logical machines"; see more at Algorithm characterizations. But not to be outdone he too presented "a plan somewhat analogous, I apprehend, to Prof. Jevon's abacus ... [And] [a]gain, corresponding to Prof. Jevons's logical machine, the following contrivance may be described. I prefer to call it merely a logical-diagram machine ... but I suppose that it could do very completely all that can be rationally expected of any logical machine".
Algorithm
775
History: Development of the notion of "algorithm"
Jacquard loom, Hollerith punch cards, telegraphy and telephony – the electromechanical relay: Bell and Newell (1971) indicate that the Jacquard loom (1801), precursor to Hollerith cards (punch cards, 1887), and "telephone switching technologies" were the roots of a tree leading to the development of the first computers. By the mid-19th century the telegraph, the precursor of the telephone, was in use throughout the world, its discrete and distinguishable encoding of letters as "dots and dashes" a common sound. By the late 19th century the ticker tape (c. 1870s) was in use, as was the use of Hollerith cards in the 1890 U.S. census. Then came the teleprinter (c. 1910) with its punched-paper use of Baudot code on tape.
Algorithm
775
History: Development of the notion of "algorithm"
Telephone-switching networks of electromechanical relays (invented 1835) was behind the work of George Stibitz (1937), the inventor of the digital adding device. As he worked in Bell Laboratories, he observed the "burdensome' use of mechanical calculators with gears. "He went home one evening in 1937 intending to test his idea... When the tinkering was over, Stibitz had constructed a binary adding device".
Algorithm
775
History: Development of the notion of "algorithm"
The mathematician Martin Davis observes the particular importance of the electromechanical relay (with its two "binary states" open and closed):
Algorithm
775
History: Development of the notion of "algorithm"
Symbols and rules: In rapid succession, the mathematics of George Boole (1847, 1854), Gottlob Frege (1879), and Giuseppe Peano (1888–1889) reduced arithmetic to a sequence of symbols manipulated by rules. Peano's The principles of arithmetic, presented by a new method (1888) was "the first attempt at an axiomatization of mathematics in a symbolic language".
Algorithm
775
History: Development of the notion of "algorithm"
But Heijenoort gives Frege (1879) this kudos: Frege's is "perhaps the most important single work ever written in logic. ... in which we see a "'formula language', that is a lingua characterica, a language written with special symbols, "for pure thought", that is, free from rhetorical embellishments ... constructed from specific symbols that are manipulated according to definite rules". The work of Frege was further simplified and amplified by Alfred North Whitehead and Bertrand Russell in their Principia Mathematica (1910–1913).
Algorithm
775
History: Development of the notion of "algorithm"
The paradoxes: At the same time a number of disturbing paradoxes appeared in the literature, in particular, the Burali-Forti paradox (1897), the Russell paradox (1902–03), and the Richard Paradox. The resultant considerations led to Kurt Gödel's paper (1931)—he specifically cites the paradox of the liar—that completely reduces rules of recursion to numbers.
Algorithm
775
History: Development of the notion of "algorithm"
Effective calculability: In an effort to solve the Entscheidungsproblem defined precisely by Hilbert in 1928, mathematicians first set about to define what was meant by an "effective method" or "effective calculation" or "effective calculability" (i.e., a calculation that would succeed). In rapid succession the following appeared: Alonzo Church, Stephen Kleene and J.B. Rosser's λ-calculus a finely honed definition of "general recursion" from the work of Gödel acting on suggestions of Jacques Herbrand (cf. Gödel's Princeton lectures of 1934) and subsequent simplifications by Kleene. Church's proof that the Entscheidungsproblem was unsolvable, Emil Post's definition of effective calculability as a worker mindlessly following a list of instructions to move left or right through a sequence of rooms and while there either mark or erase a paper or observe the paper and make a yes-no decision about the next instruction. Alan Turing's proof of that the Entscheidungsproblem was unsolvable by use of his "a- [automatic-] machine"—in effect almost identical to Post's "formulation", J. Barkley Rosser's definition of "effective method" in terms of "a machine". Kleene's proposal of a precursor to "Church thesis" that he called "Thesis I", and a few years later Kleene's renaming his Thesis "Church's Thesis" and proposing "Turing's Thesis".
Algorithm
775
History: Development of the notion of "algorithm"
Emil Post (1936) described the actions of a "computer" (human being) as follows:
Algorithm
775
History: Development of the notion of "algorithm"
His symbol space would be
Algorithm
775
History: Development of the notion of "algorithm"
Alan Turing's work preceded that of Stibitz (1937); it is unknown whether Stibitz knew of the work of Turing. Turing's biographer believed that Turing's use of a typewriter-like model derived from a youthful interest: "Alan had dreamt of inventing typewriters as a boy; Mrs. Turing had a typewriter, and he could well have begun by asking himself what was meant by calling a typewriter 'mechanical'". Given the prevalence at the time of Morse code, telegraphy, ticker tape machines, and teletypewriters, it is quite possible that all were influences on Turing during his youth.
Algorithm
775
History: Development of the notion of "algorithm"
Turing—his model of computation is now called a Turing machine—begins, as did Post, with an analysis of a human computer that he whittles down to a simple set of basic motions and "states of mind". But he continues a step further and creates a machine as a model of computation of numbers.
Algorithm
775
History: Development of the notion of "algorithm"
Turing's reduction yields the following:
Algorithm
775
History: Development of the notion of "algorithm"
"It may be that some of these change necessarily invoke a change of state of mind. The most general single operation must, therefore, be taken to be one of the following:
Algorithm
775
History: Development of the notion of "algorithm"
A few years later, Turing expanded his analysis (thesis, definition) with this forceful expression of it:
Algorithm
775
History: Development of the notion of "algorithm"
J. Barkley Rosser defined an "effective [mathematical] method" in the following manner (italicization added):
Algorithm
775
History: Development of the notion of "algorithm"
Rosser's footnote No. 5 references the work of (1) Church and Kleene and their definition of λ-definability, in particular, Church's use of it in his An Unsolvable Problem of Elementary Number Theory (1936); (2) Herbrand and Gödel and their use of recursion, in particular, Gödel's use in his famous paper On Formally Undecidable Propositions of Principia Mathematica and Related Systems I (1931); and (3) Post (1936) and Turing (1936–37) in their mechanism-models of computation.
Algorithm
775
History: Development of the notion of "algorithm"
Stephen C. Kleene defined as his now-famous "Thesis I" known as the Church–Turing thesis. But he did this in the following context (boldface in original):
Algorithm
775
History: Development of the notion of "algorithm"
A number of efforts have been directed toward further refinement of the definition of "algorithm", and activity is on-going because of issues surrounding, in particular, foundations of mathematics (especially the Church–Turing thesis) and philosophy of mind (especially arguments about artificial intelligence). For more, see Algorithm characterizations.
Annual plant
777
An annual plant is a plant that completes its life cycle, from germination to the production of seeds, within one growing season, and then dies. Globally, only 6% of all plant species and 13% of herbaceous plants (excluding trees and shrubs) are annuals. The annual life cycle has independently emerged in over 120 different plant families throughout the entire angiosperm phylogeny.
Annual plant
777
The evolutionary and ecological drivers of the annual life cycle
Traditionally, there has been a prevailing assumption that annuals have evolved from perennial ancestors. However, recent research challenges this notion, revealing instances where perennials have evolved from annual ancestors. Intriguingly, models propose that transition rates from an annual to a perennial life cycle are twice as fast as the reverse transition.
Annual plant
777
The evolutionary and ecological drivers of the annual life cycle
The life-history theory posits that annual plants are favored when adult mortality is higher than seedling (or seed) mortality, i.e., annuals will dominate environments with disturbances or high temporal variability, reducing adult survival. This hypothesis finds support in observations of increased prevalence of annuals in regions with hot-dry summers, with elevated adult mortality and high seed persistence. Furthermore, the evolution of the annual life cycle under hot-dry summer in different families makes it one of the best examples of convergent evolution. Additionally, annual prevalence is also positively affected by year-to-year variability.
Annual plant
777
The evolutionary and ecological drivers of the annual life cycle
Globally, the prevalence of annual plants shows an upward trend with an increasing human footprint. Moreover, domestic grazing has been identified as contributing to the heightened abundance of annuals in grasslands. Disturbances linked to activities like grazing and agriculture, particularly following European settlement, have facilitated the invasion of annual species from Europe and Asia into the New World.
Annual plant
777
The evolutionary and ecological drivers of the annual life cycle
In various ecosystems, the dominance of annual plants is often a temporary phase during secondary succession, particularly in the aftermath of disturbances. For instance, after fields are abandoned, annuals may initially colonize them but are eventually replaced by long-lived species. However, in certain Mediterranean systems, a unique scenario unfolds: when annuals establish dominance, perennials do not necessarily supplant them. This peculiarity is attributed to alternative stable states in the system—both annual dominance and perennial states prove stable, with the ultimate system state dependent on the initial conditions.
Annual plant
777
Traits of annuals and their implication for agriculture
Annual plants commonly exhibit a higher growth rate, allocate more resources to seeds, and allocate fewer resources to roots than perennials . In contrast to perennials, which feature long-lived plants and short-lived seeds, annual plants compensate for their lower longevity by maintaining a higher persistence of soil seed banks. These differences in life history strategies profoundly affect ecosystem functioning and services. For instance, annuals, by allocating less resources belowground, play a minor role in reducing erosion, storing organic carbon, and achieving lower nutrient- and water-use efficiencies than perennials.
Annual plant
777
Traits of annuals and their implication for agriculture
The distinctions between annual and perennial plants are notably evident in agricultural contexts. Despite constituting a minor part of global biomass, annual species stand out as the primary food source for humankind, likely owing to their greater allocation of resources to seed production, thereby enhancing agricultural productivity. In the Anthropocene epoch, marked by human impact on the environment, there has been a substantial increase in the global cover of annuals. This shift is primarily attributed to the conversion of natural systems, often dominated by perennials, into annual cropland . Currently, annual plants cover approximately 70% of croplands and contribute to around 80% of worldwide food consumption.
Annual plant
777
Molecular genetics
In 2008, it was discovered that the inactivation of only two genes in one species of annual plant leads to its conversion into a perennial plant. Researchers deactivated the SOC1 and FUL genes (which control flowering time) of Arabidopsis thaliana. This switch established phenotypes common in perennial plants, such as wood formation.
Anthophyta
779
The anthophytes are a paraphyletic grouping of plant taxa bearing flower-like reproductive structures. The group, once thought to be a clade, contained the angiosperms – the extant flowering plants, such as roses and grasses – as well as the Gnetales and the extinct Bennettitales.
Anthophyta
779
Detailed morphological and molecular studies have shown that the group is not actually monophyletic, with proposed floral homologies of the gnetophytes and the angiosperms having evolved in parallel. This makes it easier to reconcile molecular clock data that suggests that the angiosperms diverged from the gymnosperms around 320-300 mya.
Anthophyta
779
Some more recent studies have used the word anthophyte to describe a hypothetical group which includes the angiosperms and a variety of extinct seed plant groups (with various suggestions including at least some of the following groups: glossopterids, corystosperms, Petriellales Pentoxylales, Bennettitales and Caytoniales), but not the Gnetales.
Atlas (disambiguation)
780
An atlas is a collection of maps.
Atlas (disambiguation)
780
Atlas may also refer to:
Mouthwash
782
Mouthwash, mouth rinse, oral rinse, or mouth bath is a liquid which is held in the mouth passively or swirled around the mouth by contraction of the perioral muscles and/or movement of the head, and may be gargled, where the head is tilted back and the liquid bubbled at the back of the mouth.
Mouthwash
782
Usually mouthwashes are antiseptic solutions intended to reduce the microbial load in the mouth, although other mouthwashes might be given for other reasons such as for their analgesic, anti-inflammatory or anti-fungal action. Additionally, some rinses act as saliva substitutes to neutralize acid and keep the mouth moist in xerostomia (dry mouth). Cosmetic mouthrinses temporarily control or reduce bad breath and leave the mouth with a pleasant taste.
Mouthwash
782
Rinsing with water or mouthwash after brushing with a fluoride toothpaste can reduce the availability of salivary fluoride. This can lower the anti-cavity re-mineralization and antibacterial effects of fluoride. Fluoridated mouthwash may mitigate this effect or in high concentrations increase available fluoride, but is not as cost-effective as leaving the fluoride toothpaste on the teeth after brushing. A group of experts discussing post brushing rinsing in 2012 found that although there was clear guidance given in many public health advice publications to "spit, avoid rinsing with water/excessive rinsing with water" they believed there was a limited evidence base for best practice.
Mouthwash
782
Use
Common use involves rinsing the mouth with about 20–50 ml (2/3 fl oz) of mouthwash. The wash is typically swished or gargled for about half a minute and then spat out. Most companies suggest not drinking water immediately after using mouthwash. In some brands, the expectorate is stained, so that one can see the bacteria and debris. Mouthwash should not be used immediately after brushing the teeth so as not to wash away the beneficial fluoride residue left from the toothpaste. Similarly, the mouth should not be rinsed out with water after brushing. Patients were told to "spit don't rinse" after toothbrushing as part of a National Health Service campaign in the UK. A fluoride mouthrinse can be used at a different time of the day to brushing.
Mouthwash
782
Use
Gargling is where the head is tilted back, allowing the mouthwash to sit in the back of the mouth while exhaling, causing the liquid to bubble. Gargling is practiced in Japan for perceived prevention of viral infection. One commonly used way is with infusions or tea. In some cultures, gargling is usually done in private, typically in a bathroom at a sink so the liquid can be rinsed away.
Mouthwash
782
Dangerous misuse
If one drinks mouthwash, serious harm and even death can quickly result from the high alcohol content and other harmful substances in mouthwash. It is a common cause of death among homeless people during winter months, because a person can feel warmer after drinking it.
Mouthwash
782
Effects
The most-commonly-used mouthwashes are commercial antiseptics, which are used at home as part of an oral hygiene routine. Mouthwashes combine ingredients to treat a variety of oral conditions. Variations are common, and mouthwash has no standard formulation, so its use and recommendation involves concerns about patient safety. Some manufacturers of mouthwash state that their antiseptic and antiplaque mouthwashes kill the bacterial plaque that causes cavities, gingivitis, and bad breath. It is, however, generally agreed that the use of mouthwash does not eliminate the need for both brushing and flossing. The American Dental Association asserts that regular brushing and proper flossing are enough in most cases, in addition to regular dental check-ups, although they approve many mouthwashes. For many patients, however, the mechanical methods could be tedious and time-consuming, and, additionally, some local conditions may render them especially difficult. Chemotherapeutic agents, including mouthwashes, could have a key role as adjuncts to daily home care, preventing and controlling supragingival plaque, gingivitis and oral malodor.
Mouthwash
782
Effects
Minor and transient side effects of mouthwashes are very common, such as taste disturbance, tooth staining, sensation of a dry mouth, etc. Alcohol-containing mouthwashes may make dry mouth and halitosis worse, as they dry out the mouth. Soreness, ulceration and redness may sometimes occur (e.g., aphthous stomatitis or allergic contact stomatitis) if the person is allergic or sensitive to mouthwash ingredients, such as preservatives, coloring, flavors and fragrances. Such effects might be reduced or eliminated by diluting the mouthwash with water, using a different mouthwash (e.g. saltwater), or foregoing mouthwash entirely.
Mouthwash
782
Effects
Prescription mouthwashes are used prior to and after oral surgery procedures, such as tooth extraction, or to treat the pain associated with mucositis caused by radiation therapy or chemotherapy. They are also prescribed for aphthous ulcers, other oral ulcers, and other mouth pain. "Magic mouthwashes" are prescription mouthwashes compounded in a pharmacy from a list of ingredients specified by a doctor. Despite a lack of evidence that prescription mouthwashes are more effective in decreasing the pain of oral lesions, many patients and prescribers continue to use them. There has been only one controlled study to evaluate the efficacy of magic mouthwash; it shows no difference in efficacy between the most common magic-mouthwash formulation, on the one hand, and commercial mouthwashes (such as chlorhexidine) or a saline/baking soda solution, on the other. Current guidelines suggest that saline solution is just as effective as magic mouthwash in pain relief and in shortening the healing time of oral mucositis from cancer therapies.
Mouthwash
782
History
The first known references to mouth rinsing is in Ayurveda for treatment of gingivitis. Later, in the Greek and Roman periods, mouth rinsing following mechanical cleansing became common among the upper classes, and Hippocrates recommended a mixture of salt, alum, and vinegar. The Jewish Talmud, dating back about 1,800 years, suggests a cure for gum ailments containing "dough water" and olive oil. The ancient Chinese had also gargled salt water, tea and wine as a form of mouthwash after meals, due to the antiseptic properties of those liquids.
Mouthwash
782
History
Before Europeans came to the Americas, Native North American and Mesoamerican cultures used mouthwashes, often made from plants such as Coptis trifolia. Indeed, Aztec dentistry was more advanced than European dentistry of the age. Peoples of the Americas used salt water mouthwashes for sore throats, and other mouthwashes for problems such as teething and mouth ulcers.
Mouthwash
782
History
Anton van Leeuwenhoek, the famous 17th century microscopist, discovered living organisms (living, because they were mobile) in deposits on the teeth (what we now call dental plaque). He also found organisms in water from the canal next to his home in Delft. He experimented with samples by adding vinegar or brandy and found that this resulted in the immediate immobilization or killing of the organisms suspended in water. Next he tried rinsing the mouth of himself and somebody else with a mouthwash containing vinegar or brandy and found that living organisms remained in the dental plaque. He concluded—correctly—that the mouthwash either did not reach, or was not present long enough, to kill the plaque organisms. In 1892, German Richard Seifert invented mouthwash product Odol, which was produced by company founder Karl August Lingner (1861–1916) in Dresden.
Mouthwash
782
History
That remained the state of affairs until the late 1960s when Harald Loe (at the time a professor at the Royal Dental College in Aarhus, Denmark) demonstrated that a chlorhexidine compound could prevent the build-up of dental plaque. The reason for chlorhexidine's effectiveness is that it strongly adheres to surfaces in the mouth and thus remains present in effective concentrations for many hours.
Mouthwash
782
History
Since then commercial interest in mouthwashes has been intense and several newer products claim effectiveness in reducing the build-up in dental plaque and the associated severity of gingivitis, in addition to fighting bad breath. Many of these solutions aim to control the volatile sulfur compound–creating anaerobic bacteria that live in the mouth and excrete substances that lead to bad breath and unpleasant mouth taste. For example, the number of mouthwash variants in the United States of America has grown from 15 (1970) to 66 (1998) to 113 (2012).
Mouthwash
782
Research
Research in the field of microbiotas shows that only a limited set of microbes cause tooth decay, with most of the bacteria in the human mouth being harmless. Focused attention on cavity-causing bacteria such as Streptococcus mutans has led research into new mouthwash treatments that prevent these bacteria from initially growing. While current mouthwash treatments must be used with a degree of frequency to prevent this bacteria from regrowing, future treatments could provide a viable long-term solution.
Mouthwash
782
Research
A clinical trial and laboratory studies have shown that alcohol-containing mouthwash could reduce the growth of Neisseria gonorrhoeae in the pharynx. However, subsequent trials have found that there was no difference in gonorrhoea cases among men using daily mouthwash compared to those who did not use mouthwash for 12 weeks.
Mouthwash
782
Ingredients
Alcohol is added to mouthwash not to destroy bacteria but to act as a carrier agent for essential active ingredients such as menthol, eucalyptol and thymol, which help to penetrate plaque. Sometimes a significant amount of alcohol (up to 27% vol) is added, as a carrier for the flavor, to provide "bite". Because of the alcohol content, it is possible to fail a breathalyzer test after rinsing, although breath alcohol levels return to normal after 10 minutes. In addition, alcohol is a drying agent, which encourages bacterial activity in the mouth, releasing more malodorous volatile sulfur compounds. Therefore, alcohol-containing mouthwash may temporarily worsen halitosis in those who already have it, or, indeed, be the sole cause of halitosis in other individuals.
Mouthwash
782
Ingredients
It is hypothesized that alcohol in mouthwashes acts as a carcinogen (cancer-inducing agent). Generally, there is no scientific consensus about this. One review stated:
Mouthwash
782
Ingredients
There is now sufficient evidence to accept the proposition that developing oral cancer is increased or contributed to by the use of alcohol-containing mouthwashes. Whilst many of these products may have been shown to be effective in penetrating oral microbial biofilms in vitro and reducing oral bacterial load, it would be wise to restrict their use to short-term therapeutic situations if needed. Perhaps the use of mouthwashes that do not contain alcohol may be equally effective. Further, mouthrinses should be prescribed by dentists, like any other medication. There may well be a reason for the use of alcohol-containing mouthrinses, but only for a particular situation and for a limited and controlled period of time. As such, patients should be provided with written instructions for mouthwash use, and mouthwash use should be restricted to adults for short durations and specific, clearly defined reasons. It is the opinion of the authors that, in light of the evidence currently available of the association of alcohol-containing mouthwashes with the development of oral cancer, it would be inadvisable for oral healthcare professionals to recommend the long-term use of alcohol-containing mouthwashes.
Mouthwash
782
Ingredients
The same researchers also state that the risk of acquiring oral cancer rises almost five times for users of alcohol-containing mouthwash who neither smoke nor drink (with a higher rate of increase for those who do). In addition, the authors highlight side effects from several mainstream mouthwashes that included dental erosion and accidental poisoning of children. The review garnered media attention and conflicting opinions from other researchers. Yinka Ebo of Cancer Research UK disputed the findings, concluding that "there is still not enough evidence to suggest that using mouthwash that contains alcohol will increase the risk of mouth cancer". Studies conducted in 1985, 1995, 2003, and 2012 did not support an association between alcohol-containing mouth rinses and oral cancer. Andrew Penman, chief executive of The Cancer Council New South Wales, called for further research on the matter. In a March 2009 brief, the American Dental Association said "the available evidence does not support a connection between oral cancer and alcohol-containing mouthrinse". Many newer brands of mouthwash are alcohol-free, not just in response to consumer concerns about oral cancer, but also to cater for religious groups who abstain from alcohol consumption.
Mouthwash
782
Ingredients
In painful oral conditions such as aphthous stomatitis, analgesic mouthrinses (e.g. benzydamine mouthwash, or "Difflam") are sometimes used to ease pain, commonly used before meals to reduce discomfort while eating.
Mouthwash
782
Ingredients
Benzoic acid acts as a buffer.
Mouthwash
782
Ingredients
Betamethasone is sometimes used as an anti-inflammatory, corticosteroid mouthwash. It may be used for severe inflammatory conditions of the oral mucosa such as the severe forms of aphthous stomatitis.
Mouthwash
782
Ingredients
Cetylpyridinium chloride containing mouthwash (e.g. 0.05%) is used in some specialized mouthwashes for halitosis. Cetylpyridinium chloride mouthwash has less anti-plaque effect than chlorhexidine and may cause staining of teeth, or sometimes an oral burning sensation or ulceration.
Mouthwash
782
Ingredients
Chlorhexidine digluconate is a chemical antiseptic and is used in a 0.05–0.2% solution as a mouthwash. There is no evidence to support that higher concentrations are more effective in controlling dental plaque and gingivitis. A randomized clinical trial conducted in Rabat University in Morocco found better results in plaque inhibition when chlorohexidine with alcohol base 0.12% was used, when compared to an alcohol-free 0.1% chlorhexidine mouthrinse.
Mouthwash
782
Ingredients
Chlorhexidine has good substantivity (the ability of a mouthwash to bind to hard and soft tissues in the mouth). It has anti-plaque action, and also some anti-fungal action. It is especially effective against Gram-negative rods. The proportion of Gram-negative rods increase as gingivitis develops, so it is also used to reduce gingivitis. It is sometimes used as an adjunct to prevent dental caries and to treat periodontal disease, although it does not penetrate into periodontal pockets well. Chlorhexidine mouthwash alone is unable to prevent plaque, so it is not a substitute for regular toothbrushing and flossing. Instead, chlorhexidine mouthwash is more effective when used as an adjunctive treatment with toothbrushing and flossing. In the short term, if toothbrushing is impossible due to pain, as may occur in primary herpetic gingivostomatitis, chlorhexidine mouthwash is used as a temporary substitute for other oral hygiene measures. It is not suited for use in acute necrotizing ulcerative gingivitis, however. Rinsing with chlorhexidine mouthwash before and after a tooth extraction may reduce the risk of a dry socket. Other uses of chlorhexidine mouthwash include prevention of oral candidiasis in immunocompromised persons, treatment of denture-related stomatitis, mucosal ulceration/erosions and oral mucosal lesions, general burning sensation and many other uses.
Mouthwash
782
Ingredients
Chlorhexidine mouthwash is known to have minor adverse effects. Chlorhexidine binds to tannins, meaning that prolonged use in persons who consume coffee, tea or red wine is associated with extrinsic staining (i.e. removable staining) of teeth. A systematic review of commercial chlorhexidine products with anti-discoloration systems (ADSs) found that the ADSs were able to reduce tooth staining without affecting the beneficial effects of chlorhexidine. Chlorhexidine mouthwash can also cause taste disturbance or alteration. Chlorhexidine is rarely associated with other issues like overgrowth of enterobacteria in persons with leukemia, desquamation, irritation, and stomatitis of oral mucosa, salivary gland pain and swelling, and hypersensitivity reactions including anaphylaxis.
Mouthwash
782
Ingredients
Hexetidine also has anti-plaque, analgesic, astringent and anti-malodor properties, but is considered an inferior alternative to chlorhexidine.
Mouthwash
782
Ingredients
In traditional Ayurvedic medicine, the use of oil mouthwashes is called "Kavala" ("oil swishing") or "Gandusha", and this practice has more recently been re-marketed by the complementary and alternative medicine industry as "oil pulling". Its promoters claim it works by "pulling out" "toxins", which are known as ama in Ayurvedic medicine, and thereby reducing inflammation. Ayurvedic literature claims that oil pulling is capable of improving oral and systemic health, including a benefit in conditions such as headaches, migraines, diabetes mellitus, asthma, and acne, as well as whitening teeth.
Mouthwash
782
Ingredients
Oil pulling has received little study and there is little evidence to support claims made by the technique's advocates. When compared with chlorhexidine in one small study, it was found to be less effective at reducing oral bacterial load, and the other health claims of oil pulling have failed scientific verification or have not been investigated. There is a report of lipid pneumonia caused by accidental inhalation of the oil during oil pulling.
Mouthwash
782
Ingredients
The mouth is rinsed with approximately one tablespoon of oil for 10–20 minutes then spat out. Sesame oil, coconut oil and ghee are traditionally used, but newer oils such as sunflower oil are also used.
Mouthwash
782
Ingredients
Phenolic compounds and monoterpenes include essential oil constituents that have some antibacterial properties, such as eucalyptol, eugenol, hinokitiol, menthol, phenol, or thymol. Essential oils are oils which have been extracted from plants. Mouthwashes based on essential oils could be more effective than traditional mouthcare as anti-gingival treatments. They have been found effective in reducing halitosis, and are being used in several commercial mouthwashes.
Mouthwash
782
Ingredients
Anti-cavity mouthwashes use sodium fluoride to protect against tooth decay. Fluoride-containing mouthwashes are used as prevention for dental caries for individuals who are considered at higher risk for tooth decay, whether due to xerostomia related to salivary dysfunction or side effects of medication, to not drinking fluoridated water, or to being physically unable to care for their oral needs (brushing and flossing), and as treatment for those with dentinal hypersensitivity, gingival recession/ root exposure.
Mouthwash
782
Ingredients
Flavoring agents include sweeteners such as sorbitol, sucralose, sodium saccharin, and xylitol, which stimulate salivary function due to their sweetness and taste and helps restore the mouth to a neutral level of acidity.
Mouthwash
782
Ingredients
Xylitol rinses double as a bacterial inhibitor, and have been used as substitute for alcohol to avoid dryness of mouth associated with alcohol.
Mouthwash
782
Ingredients
Hydrogen peroxide can be used as an oxidizing mouthwash (e.g. Peroxyl, 1.5%). It kills anaerobic bacteria, and also has a mechanical cleansing action when it froths as it comes into contact with debris in mouth. It is often used in the short term to treat acute necrotising ulcerative gingivitis. Side effects can occur with prolonged use, including hypertrophy of the lingual papillae.
Mouthwash
782
Ingredients
Enzymes and non-enzymatic proteins, such as lactoperoxidase, lysozyme, and lactoferrin, have been used in mouthwashes (e.g., Biotene) to reduce levels of oral bacteria, and, hence, of the acids produced by these bacteria.
Mouthwash
782
Ingredients
Oral lidocaine is useful for the treatment of mucositis symptoms (inflammation of mucous membranes) induced by radiation or chemotherapy. There is evidence that lidocaine anesthetic mouthwash has the potential to be systemically absorbed, when it was tested in patients with oral mucositis who underwent a bone marrow transplant.
Mouthwash
782
Ingredients
Methyl salicylate functions as an antiseptic, antiinflammatory, and analgesic agent, a flavoring, and a fragrance. Methyl salicylate has some anti-plaque action, but less than chlorhexidine. Methyl salicylate does not stain teeth.
Mouthwash
782
Ingredients
Nystatin suspension is an antifungal ingredient used for the treatment of oral candidiasis.
Mouthwash
782
Ingredients
A randomized clinical trial found promising results in controlling and reducing dentine hypersensitivity when potassium oxalate mouthwash was used in conjugation with toothbrushing.
Mouthwash
782
Ingredients
A 2005 study found that gargling three times a day with simple water or with a povidone-iodine solution was effective in preventing upper respiratory infection and decreasing the severity of symptoms if contracted. Other sources attribute the benefit to a simple placebo effect.
Mouthwash
782
Ingredients
PVP-I in general covers "a wider virucidal spectrum, covering both enveloped and nonenveloped viruses, than the other commercially available antiseptics", which also includes the novel SARS-CoV-2 Virus.
Mouthwash
782
Ingredients
Sanguinarine-containing mouthwashes are marketed as anti-plaque and anti-malodor treatments. Sanguinarine is a toxic alkaloid herbal extract, obtained from plants such as Sanguinaria canadensis (bloodroot), Argemone mexicana (Mexican prickly poppy), and others. However, its use is strongly associated with the development of leukoplakia (a white patch in the mouth), usually in the buccal sulcus. This type of leukoplakia has been termed "sanguinaria-associated keratosis", and more than 80% of people with leukoplakia in the vestibule of the mouth have used this substance. Upon stopping contact with the causative substance, the lesions may persist for years. Although this type of leukoplakia may show dysplasia, the potential for malignant transformation is unknown. Ironically, elements within the complementary and alternative medicine industry promote the use of sanguinaria as a therapy for cancer.
Mouthwash
782
Ingredients
Sodium bicarbonate is sometimes combined with salt to make a simple homemade mouthwash, indicated for any of the reasons that a saltwater mouthwash might be used. Pre-mixed mouthwashes of 1% sodium bicarbonate and 1.5% sodium chloride in aqueous solution are marketed, although pharmacists will easily be able to produce such a formulation from the base ingredients when required. Sodium bicarbonate mouthwash is sometimes used to remove viscous saliva and to aid visualization of the oral tissues during examination of the mouth.
Mouthwash
782
Ingredients
Saline has a mechanical cleansing action and an antiseptic action, as it is a hypertonic solution in relation to bacteria, which undergo lysis. The heat of the solution produces a therapeutic increase in blood flow (hyperemia) to the surgical site, promoting healing. Hot saltwater mouthwashes also encourage the draining of pus from dental abscesses. In contrast, if heat is applied on the side of the face (e.g., hot water bottle) rather than inside the mouth, it may cause a dental abscess to drain extra-orally, which is later associated with an area of fibrosis on the face (see cutaneous sinus of dental origin).
Mouthwash
782
Ingredients
Saltwater mouthwashes are also routinely used after oral surgery, to keep food debris out of healing wounds and to prevent infection. Some oral surgeons consider saltwater mouthwashes the mainstay of wound cleanliness after surgery. In dental extractions, hot saltwater mouthbaths should start about 24 hours after a dental extraction. The term mouth bath implies that the liquid is passively held in the mouth, rather than vigorously swilled around (which could dislodge a blood clot). Once the blood clot has stabilized, the mouthwash can be used more vigorously. These mouthwashes tend to be advised for use about 6 times per day, especially after meals (to remove food from the socket).