If left untreated, cavities can lead to infections, tooth pain, and tooth loss, and are associated with weight gain, impaired quality of life, and even negative school performance.

Community tap water has been fluoridated in the United States since for the prevention of dental caries. The current recommended amount is 0. Cohort studies have shown that fluoridated water lowers the risk of tooth decay and premature tooth loss in children and adults.

The U. Preventive Services Task Force and the American Dental Association provide guidelines for fluoride supplements in children 6 months to 16 years ranging from 0. Obtaining fluoride topically, such as brushing or rinsing with toothpaste or mouthwash containing fluoride, also effectively strengthens tooth enamel and protects against dental caries.

Fluoride in trace amounts is essential for normal bone growth. It stimulates bone-building cells called osteoblasts and hormones such as insulin-like growth factor. In adults, however, the research does not support the use of fluoride supplements to prevent fractures or improve bone density such as for osteopenia or osteoporosis.

A randomized double-blind placebo-controlled trial of postmenopausal women with osteopenia early bone loss followed for one year found that compared with the placebo, fluoride supplements of varying amounts showed no changes in bone mineral density.

Chronic excessive intakes of fluoride can lead to skeletal fluorosis, a condition that causes bone changes ranging from osteoporosis significant bone loss to osteosclerosis abnormal hardening of bone that occurs from an increase in bone-building osteoblast cells and increased risk of fractures.

Trace amounts of fluoride are found naturally in various foods, though people obtain most fluoride from fluoridated water and toothpastes. Brewed black tea and coffee naturally contain fluoride as the plants absorb the mineral in soil.

Shellfish may contain fluoride that collects in their shells and muscles. Questions have been posed about the continued need for and safety of community fluoridated water, with concerns about ingesting excessive fluoride and potential negative health effects.

Adding fuel to the fire, a top medical journal labeled fluoride as a human developmental neurotoxicant, placing it in the same category as toxic metals like lead and arsenic. A more contentious claim suggests that ingesting excess fluoride largely from community fluoridated water causes cognitive deficits and lowered intelligence in children.

A comprehensive review of epidemiological, animal, and laboratory studies found an association, but the authors noted various confounding factors present that may have contributed to cognitive deficits, including low birth weight, socioeconomic status, and exposure to other neurotoxic chemicals.

However, these high levels were considered toxic and a likely contributor to the deficits. Lower fluoride amounts of mg per liter in other animal studies are still much higher than that provided in community fluoridated water. Another criticism is that cross-sectional observational studies are not intended to make direct cause-and-effect conclusions.

Some scientists argue that IQs overall have increased since introducing community fluoridated water, although improved education and early intervention services are other likely contributors.

In adults, there is concern of the accumulation of excess fluoride in bones that may increase the risk of fractures.

Research has shown mixed results, from a positive association, to no association, to even a protective effect of fluoride. A meta-analysis looking at 13 cohort studies did not find an association of exposure to fluoride from drinking water ranging from 7 to 44 years and an increased risk of hip fractures in older adults.

Bone formation also decreases with age, so less fluoride is absorbed and needed by bone tissue. In contrast, a cohort study published in looking at the association of fractures in postmenopausal women and fluoride as measured in urine and dietary intakes found higher rates of hip fractures when comparing the highest to lowest intakes of fluoride and urinary fluoride.

The mean dietary intake was about 2 mg daily that included drinking water fluoridated at about 1 mg per liter. There also remains a question of potential health risks with specific conditions, such as kidney disease in which people may not be able to excrete excess fluoride if exposed, increasing the risk of toxicity.

There is also a risk of fluoride causing chronic kidney disease CKD , as shown in studies of people exposed to excessive fluoride due to unusually high levels in the groundwater who develop CKD.

Still, fluoride is required by the body in only trace amounts, and it is unclear of the effects of lifetime exposure to fluoride through community water and fluoride-supplemented dental products in specific situations such as CKD.

More research is needed to see the health effects of fluoride in people with CKD and if they may benefit from limiting the ingestion of fluoride. Water has been fluoridated in the U. and in other countries since the s, and research to date has not shown negative health consequences for the general population that outweigh its protective benefits.

Because of the known risk of severe health problems in children and adults associated with dental caries, national health organizations such as the Centers for Disease Control and Prevention CDC , the American Academy of Pediatrics AAP and the American Dental Association ADA continue to support the safety, effectiveness, and cost effectiveness of community fluoridated water.

Fluoride is not considered an essential nutrient but plays an important role in dental and possibly bone health. A deficiency of fluoride can lead to dental caries and potentially bone problems. In areas where water naturally contains higher levels of fluoride, community water systems must ensure that the maximum level is no higher than 4 ppm.

Read the article in Spanish. This article examines what fluoride is, why producers add it to toothpaste, the benefits and risks of fluoride, and how to choose the best toothpaste.

Twelve years ago, Juneau, AK, stopped adding fluoride to community water sources. A newly published study looks at how this has affected its….

Fluoride treatment may offer benefits to those at risk of tooth decay. Natural health advocates, however, question the safety of fluoride. We look at….

Some early research suggests that xylitol gum may help prevent cavities, treat gum disease, and have other health benefits.

Learn more here. A cavity may cause white spots on the teeth, visible holes or gaps, or pain. This article explores how to know if you have a cavity and how to prevent…. My podcast changed me Can 'biological race' explain disparities in health?

Why Parkinson's research is zooming in on the gut Tools General Health Drugs A-Z Health Hubs Health Tools Find a Doctor BMI Calculators and Charts Blood Pressure Chart: Ranges and Guide Breast Cancer: Self-Examination Guide Sleep Calculator Quizzes RA Myths vs Facts Type 2 Diabetes: Managing Blood Sugar Ankylosing Spondylitis Pain: Fact or Fiction Connect About Medical News Today Who We Are Our Editorial Process Content Integrity Conscious Language Newsletters Sign Up Follow Us.

Medical News Today. Health Conditions Health Products Discover Tools Connect. Why do we have fluoride in our water? Medically reviewed by Karen Cross, FNP, MSN — By Yvette Brazier on February 21, Risks Uses Side Effects Benefits Facts Controversy Takeaway Fluoride is found naturally in soil, water, and foods.

Fast facts about fluoride Fluoride comes from fluroine, which is a common, natural, and abundant element. Adding fluoride to the water supply reduces the incidence of tooth decay. Fluoride protects teeth from decay by demineralization and remineralization.

Too much fluoride can lead to dental fluorosis or skeletal fluorosis, which can damage bones and joints. Was this helpful? Side effects. How we reviewed this article: Sources. Medical News Today has strict sourcing guidelines and draws only from peer-reviewed studies, academic research institutions, and medical journals and associations.

We avoid using tertiary references. We link primary sources — including studies, scientific references, and statistics — within each article and also list them in the resources section at the bottom of our articles. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

Share this article. Latest news Ovarian tissue freezing may help delay, and even prevent menopause. RSV vaccine errors in babies, pregnant people: Should you be worried?

Scientists discover biological mechanism of hearing loss caused by loud noise — and find a way to prevent it. Fluoride exerts its major effect by interfering with the demineralization mechanism of tooth decay. Tooth decay is an infectious disease , the key feature of which is an increase within dental plaque of bacteria such as Streptococcus mutans and Lactobacillus.

These produce organic acids when carbohydrates, especially sugar, are eaten. After the sugar is gone, some of the mineral loss can be recovered—or remineralized —from ions dissolved in the saliva. Cavities result when the rate of demineralization exceeds the rate of remineralization, typically in a process that requires many months or years.

All fluoridation methods, including water fluoridation, create low levels of fluoride ions in saliva and plaque fluid, thus exerting a topical or surface effect. A person living in an area with fluoridated water may experience rises of fluoride concentration in saliva to about 0.

Fluoride's effects depend on the total daily intake of fluoride from all sources. High fluoride levels have been found in other foods, including barley, cassava, corn, rice, taro, yams, and fish protein concentrate.

The U. Institute of Medicine has established Dietary Reference Intakes for fluoride: Adequate Intake values range from 0. However, these values differ greatly among the world's regions: for example, in Sichuan, China the average daily fluoride intake is only 0.

The views on the most effective method for community prevention of tooth decay are mixed. The Australian government review states that water fluoridation is the most effective means of achieving fluoride exposure that is community-wide. Fluoride toothpaste is the most widely used and rigorously evaluated fluoride treatment.

The effectiveness of salt fluoridation is about the same as that of water fluoridation, if most salt for human consumption is fluoridated. Fluoridated salt reaches the consumer in salt at home, in meals at school and at large kitchens, and in bread.

For example, Jamaica has just one salt producer, but a complex public water supply; it started fluoridating all salt in , achieving a decline in cavities. Universal salt fluoridation is also practiced in Colombia and the Swiss Canton of Vaud ; in Germany fluoridated salt is widely used in households but unfluoridated salt is also available, giving consumers a choice.

Milk fluoridation is practiced by the Borrow Foundation in some parts of Bulgaria, Chile, Peru, Russia, Macedonia, Thailand and the UK. Depending on location, the fluoride is added to milk, to powdered milk , or to yogurt. For example, milk powder fluoridation is used in rural Chilean areas where water fluoridation is not technically feasible.

Other public-health strategies to control tooth decay, such as education to change behavior and diet, have lacked impressive results. A Australian review concluded that water fluoridation is the most effective and socially the most equitable way to expose entire communities to fluoride's cavity-prevention effects.

As of November , a total of about million people worldwide received artificially fluoridated water. The majority of those were in the United States.

About 40 million worldwide received water that was naturally fluoridated to recommended levels. Much of the early work on establishing the connection between fluoride and dental health was performed by scientists in the U.

during the early 20th century, and the U. was the first country to implement public water fluoridation on a wide scale. In , an estimated received artificially fluoridated water. population was receiving fluoridated water.

In some locations, notably parts of Africa, China, and India, natural fluoridation exceeds recommended levels. Communities have discontinued water fluoridation in some countries, including Finland, Germany, Japan, the Netherlands, and Switzerland.

In three other West European countries, Greece, Austria and the Netherlands, the legal framework for production and marketing of fluoridated edible salt exists. The Slovak Republic had the equipment to treat salt by ; in the other four countries attempts to introduce fluoridated salt were not successful.

This approach is therefore not accepted in most countries in the world. The history of water fluoridation can be divided into three periods. The first c. The second c.

The third period, from on, focused on adding fluoride to community water supplies. In the first half of the 19th century, investigators established that fluoride occurs with varying concentrations in teeth, bone, and drinking water. In the second half they speculated that fluoride would protect against tooth decay, proposed supplementing the diet with fluoride, and observed mottled enamel now called severe dental fluorosis without knowing the cause.

of fluorine in some suitable natural form to fortify the teeth of the next generation". The foundation of water fluoridation in the U.

was the research of the dentist Frederick McKay — McKay spent thirty years investigating the cause of what was then known as the Colorado brown stain, which produced mottled but also cavity-free teeth; with the help of G.

Black and other researchers, he established that the cause was fluoride. In , an Alcoa chemist, H. Churchill, concerned about a possible link between aluminum and staining, analyzed water from several areas where the staining was common and found that fluoride was the common factor.

In the s and early s, H. Trendley Dean and colleagues at the newly created U. The results, published in , showed significant reduction of cavities.

Fluoridation became an official policy of the U. Public Health Service by , and by water fluoridation had become widely used in the U.

population on public water systems were receiving fluoridated water, amounting to population; 3. McKay's work had established that fluorosis occurred before tooth eruption. Dean and his colleagues assumed that fluoride's protection against cavities was also pre-eruptive, and this incorrect assumption was accepted for years.

By , however, the topical effects of fluoride in both water and toothpaste were well understood, and it had become known that a constant low level of fluoride in the mouth works best to prevent cavities.

Larger water systems have lower per capita cost, and the cost is also affected by the number of fluoride injection points in the water system, the type of feeder and monitoring equipment, the fluoride chemical and its transportation and storage, and water plant personnel expertise.

Although a workshop on cost-effectiveness of cavity prevention concluded that water fluoridation is one of the few public health measures that save more money than they cost, little high-quality research has been done on the cost-effectiveness and solid data are scarce.

review estimated that on average, sealing first permanent molars saves costs when they are decaying faster than 0. was cost-effective, and that it was more so in larger communities. data from to indicate that when water fluoridation is introduced into a community, there are significant decreases in the number of employees per dental firm and the number of dental firms.

The data suggest that some dentists respond to the demand shock by moving to non-fluoridated areas and by retraining as specialists. The water fluoridation controversy arises from political, moral, ethical, economic, and safety concerns regarding the water fluoridation of public water supplies.

Those opposed argue that water fluoridation has no or little cariostatic benefits, may cause serious health problems, is not effective enough to justify the costs, is pharmacologically obsolete, [2] [] [] [] and presents a moral conflict between the common good and individual rights.

Contents move to sidebar hide. Article Talk. Read View source View history. Tools Tools. What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item. Download as PDF Printable version.

In other projects. Wikimedia Commons Wikiversity. Addition of fluoride to a water supply to reduce tooth decay. Main article: Fluoridation by country. See also: History of water supply and sanitation. Main article: Water fluoridation controversy. Community Dentistry and Oral Epidemiology. doi : PMID Centers for Disease Control and Prevention".

Recommendations and Reports. August See also lay summary from CDC, Clinical Oral Investigations. S2CID How Much Is That in Real Money?

A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States: Addenda et Corrigenda PDF. American Antiquarian Society. A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States PDF.

Retrieved 28 May In Wang LK, Hung YT, Shammas NK eds. Advanced Physicochemical Treatment Processes. Handbook of Environmental Engineering 4. Humana Press. ISBN See also J. Fawell, et al Fluoride in Drinking-water.

WHO, Quote: "Concentrations in drinking-water of about 1 mg l—1 are associated with a lower incidence of dental caries, particularly in children, whereas excess intake of fluoride can result in dental fluorosis.

In severe cases this can result in erosion of enamel. June The Cochrane Database of Systematic Reviews.

Early symptoms include joint pain and stiffness. Over time, it can alter bone structure and cause the calcification of ligaments. It tends to result from long-term exposure to high levels of fluoride, often in drinking water.

Several things can cause excessive fluoride in water, including accidental contamination from fires or explosions. Some areas, including large parts of Africa and Asia, also have large geologic deposits of fluoride, which can contaminate water supplies.

In the case of a year-old American man with skeletal fluorosis, experts concluded it was likely due to swallowing toothpaste. Researchers from around the world have conducted hundreds of studies that look at the safety of adding low concentrations of fluoride to drinking water.

However, some people claim that fluoridated water causes a variety of health problems, including:. The research behind these claims is mixed. For example, a study found that childhood exposure to fluoridated water was linked to higher rates of bone cancer in males.

Studies looking at the link between fluoride and low IQ scores in children also have mixed results. A review of existing research concluded that there may be a link between the two, but noted that more large, high-quality studies are needed.

Not every city in the United States fluoridates its drinking water. The decision about whether or not to fluoridate is made by each city. However, the CDC has a tool you can use to check your local water supply if you live in certain states.

This tool will tell you whether your city fluoridates its water. Fluoride is a naturally occurring mineral used in many dental products to strengthen tooth enamel and prevent cavities. While the amount added to drinking water is considered to be relatively safe, exposure to high levels of fluoride may be linked to several health issues.

You can also opt for fluoride-free dental products, especially if you have young children. Healthline and our partners may receive a portion of revenues if you make a purchase using a link above. Our experts continually monitor the health and wellness space, and we update our articles when new information becomes available.

Fluoride helps improve dental health, but it may be dangerous in high amounts. Learn more about fluoride and its benefits and risks.

Fluoride toothpaste is recommended by most dentists. But some people also have concerns about its safety. Stannous fluoride can be found in over-the-counter toothpaste and mouthwash. Fluoride treatment can help protect your teeth and may be recommended for both children and adults.

Fluoride is also found in toothpaste, some dietary…. Baby teeth are temporary but important. Most cavities take several months or years to form. However, multiple factors can influence how quickly tooth decay progresses, including oral hygiene,.

The idea of tooth worms is an ancient myth. Here's why so many different ancient people believed they existed and how they treated cavities. Cavity symptoms or signs of tooth decay can include sensitivity to heat, cold, or sweet foods.

You may also have tooth pain or notice discoloration…. A Quiz for Teens Are You a Workaholic? How Well Do You Sleep? Health Conditions Discover Plan Connect. What Is Fluoride, and Is It Safe? Medically reviewed by Christine Frank, DDS — By Jacquelyn Cafasso — Updated on July 3, Uses Benefits Side effects Controversy Check your water Takeaway.

How we vet brands and products Healthline only shows you brands and products that we stand behind. Our team thoroughly researches and evaluates the recommendations we make on our site. To establish that the product manufacturers addressed safety and efficacy standards, we: Evaluate ingredients and composition: Do they have the potential to cause harm?

Fact-check all health claims: Do they align with the current body of scientific evidence? Assess the brand: Does it operate with integrity and adhere to industry best practices? We do the research so you can find trusted products for your health and wellness. Read more about our vetting process.

For example, Jamaica has just one salt producer, but a complex public water supply; it started fluoridating all salt in , achieving a decline in cavities. Universal salt fluoridation is also practiced in Colombia and the Swiss Canton of Vaud ; in Germany fluoridated salt is widely used in households but unfluoridated salt is also available, giving consumers a choice.

Milk fluoridation is practiced by the Borrow Foundation in some parts of Bulgaria, Chile, Peru, Russia, Macedonia, Thailand and the UK. Depending on location, the fluoride is added to milk, to powdered milk , or to yogurt.

For example, milk powder fluoridation is used in rural Chilean areas where water fluoridation is not technically feasible. Other public-health strategies to control tooth decay, such as education to change behavior and diet, have lacked impressive results.

A Australian review concluded that water fluoridation is the most effective and socially the most equitable way to expose entire communities to fluoride's cavity-prevention effects. As of November , a total of about million people worldwide received artificially fluoridated water. The majority of those were in the United States.

About 40 million worldwide received water that was naturally fluoridated to recommended levels. Much of the early work on establishing the connection between fluoride and dental health was performed by scientists in the U. during the early 20th century, and the U.

was the first country to implement public water fluoridation on a wide scale. In , an estimated received artificially fluoridated water. population was receiving fluoridated water. In some locations, notably parts of Africa, China, and India, natural fluoridation exceeds recommended levels.

Communities have discontinued water fluoridation in some countries, including Finland, Germany, Japan, the Netherlands, and Switzerland. In three other West European countries, Greece, Austria and the Netherlands, the legal framework for production and marketing of fluoridated edible salt exists.

The Slovak Republic had the equipment to treat salt by ; in the other four countries attempts to introduce fluoridated salt were not successful. This approach is therefore not accepted in most countries in the world. The history of water fluoridation can be divided into three periods.

The first c. The second c. The third period, from on, focused on adding fluoride to community water supplies. In the first half of the 19th century, investigators established that fluoride occurs with varying concentrations in teeth, bone, and drinking water. In the second half they speculated that fluoride would protect against tooth decay, proposed supplementing the diet with fluoride, and observed mottled enamel now called severe dental fluorosis without knowing the cause.

of fluorine in some suitable natural form to fortify the teeth of the next generation". The foundation of water fluoridation in the U. was the research of the dentist Frederick McKay — McKay spent thirty years investigating the cause of what was then known as the Colorado brown stain, which produced mottled but also cavity-free teeth; with the help of G.

Black and other researchers, he established that the cause was fluoride. In , an Alcoa chemist, H. Churchill, concerned about a possible link between aluminum and staining, analyzed water from several areas where the staining was common and found that fluoride was the common factor.

In the s and early s, H. Trendley Dean and colleagues at the newly created U. The results, published in , showed significant reduction of cavities. Fluoridation became an official policy of the U. Public Health Service by , and by water fluoridation had become widely used in the U.

population on public water systems were receiving fluoridated water, amounting to population; 3. McKay's work had established that fluorosis occurred before tooth eruption.

Dean and his colleagues assumed that fluoride's protection against cavities was also pre-eruptive, and this incorrect assumption was accepted for years.

By , however, the topical effects of fluoride in both water and toothpaste were well understood, and it had become known that a constant low level of fluoride in the mouth works best to prevent cavities. Larger water systems have lower per capita cost, and the cost is also affected by the number of fluoride injection points in the water system, the type of feeder and monitoring equipment, the fluoride chemical and its transportation and storage, and water plant personnel expertise.

Although a workshop on cost-effectiveness of cavity prevention concluded that water fluoridation is one of the few public health measures that save more money than they cost, little high-quality research has been done on the cost-effectiveness and solid data are scarce.

review estimated that on average, sealing first permanent molars saves costs when they are decaying faster than 0.

was cost-effective, and that it was more so in larger communities. data from to indicate that when water fluoridation is introduced into a community, there are significant decreases in the number of employees per dental firm and the number of dental firms.

The data suggest that some dentists respond to the demand shock by moving to non-fluoridated areas and by retraining as specialists. The water fluoridation controversy arises from political, moral, ethical, economic, and safety concerns regarding the water fluoridation of public water supplies.

Those opposed argue that water fluoridation has no or little cariostatic benefits, may cause serious health problems, is not effective enough to justify the costs, is pharmacologically obsolete, [2] [] [] [] and presents a moral conflict between the common good and individual rights.

Contents move to sidebar hide. Article Talk. Read View source View history. Tools Tools. What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item. Download as PDF Printable version.

In other projects. Wikimedia Commons Wikiversity. Addition of fluoride to a water supply to reduce tooth decay. Main article: Fluoridation by country. See also: History of water supply and sanitation. Main article: Water fluoridation controversy.

Community Dentistry and Oral Epidemiology. doi : PMID Centers for Disease Control and Prevention". Recommendations and Reports. August See also lay summary from CDC, Clinical Oral Investigations.

S2CID How Much Is That in Real Money? A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States: Addenda et Corrigenda PDF.

American Antiquarian Society. A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States PDF. Retrieved 28 May In Wang LK, Hung YT, Shammas NK eds. Advanced Physicochemical Treatment Processes. Handbook of Environmental Engineering 4.

Humana Press. ISBN See also J. Fawell, et al Fluoride in Drinking-water. WHO, Quote: "Concentrations in drinking-water of about 1 mg l—1 are associated with a lower incidence of dental caries, particularly in children, whereas excess intake of fluoride can result in dental fluorosis.

In severe cases this can result in erosion of enamel. June The Cochrane Database of Systematic Reviews. PMC European Commission Scientific Committee on Health and Environmental Risks SCHER.

Retrieved 18 April Wisconsin Dental Association. Archived from the original on 1 August Retrieved 6 February A systematic review of the efficacy and safety of fluoridation PDF.

Archived from the original PDF on 14 October Retrieved 13 October Summary: Yeung CA Evidence-Based Dentistry. See also lay summary from NHMRC, Report website: "Fluoridation of drinking water: a systematic review of its efficacy and safety".

NHS Centre for Reviews and Dissemination. Retrieved 26 May Authors' summary: McDonagh MS, Whiting PF, Wilson PM, et al. October Authors' commentary: Treasure ET, Chestnutt IG, Whiting P, McDonagh M, Wilson P, Kleijnen J May British Dental Journal. Fluoride in Drinking-water PDF. World Health Organization.

Bulletin of the World Health Organization. Archived from the original on 14 March One in a Million: The facts about water fluoridation 3rd ed. Manchester: British Fluoridation Society.

Archived from the original PDF on 22 November Retrieved 19 November Retrieved 19 April British Fluoridation Society. Archived from the original PDF on 6 March Morbidity and Mortality Weekly Report. Nutr Bull. Sociol Perspect. BMC Oral Health. Journal of Public Health Dentistry.

International Dental Journal. In Ward JW, Warren C ed. Silent Victories: The History and Practice of Public Health in Twentieth-century America. Oxford University Press. Advances in Dental Research. National Institute of Dental and Craniofacial Research.

Archived from the original PDF on 4 March Centers for Disease Control. Archived from the original PDF on 7 October Retrieved 10 December Water Fluoridation Principles and Practices. Manual of Water Supply Practices. M4 5th ed. American Water Works Association.

In Tressaud A, Haufe G eds. Fluorine and Health. Archived from the original on 21 February Retrieved 27 January Division of Oral Health, National Center for Prevention Services, CDC. Retrieved 29 December September Journal of Dental Research.

hdl : EFSA Journal. Food and Drug Administration. Retrieved 6 May Rev Environ Sci Biotechnol. Bibcode : RESBT Retrieved 28 April European Archives of Paediatric Dentistry. Journal of Political Economy. ISSN Archived from the original on 19 April Retrieved 13 February A systematic review of published studies".

Journal of Epidemiology and Community Health.