In 1901, a Colorado dentist named Dr. Frederick McKay began decades of research to discover and ultimately prove to the world that fluoride, a mineral found in rocks and soil, prevented tooth decay. In the 1930s, scientists started examining the relationship between fluoride and tooth decay after it was noticed children drinking water high in fluoride had fewer cavities.
In the 1930s, a dentist named Dr. H. Trendley Dean took McKay’s research to a new level. Dr. Dean was head of the Dental Hygiene Unit at the National Institutes of Health. By the late ’30s, he and his research team discovered that fluoride levels of up to 1.0 parts per million (PPM)in water generally did not cause spots on enamel. Dr. Dean realized that most supplies of drinking water in the U.S. were well below 1.0 PPM, and he wanted to learn whether adding more fluoride would affect the rate of tooth decay among children.
Eventually, it was determined that for children younger than 8, fluoride helps strengthen the permanent teeth developing under the gums. For adults, drinking water with fluoride continues to support tooth enamel.
According to the state health department, fluoride prevents tooth decay in three ways: It prevents plaque bacteria from producing acid; it is absorbed into the tooth enamel, preventing the acids from entering; and it remineralizes teeth after attacks by acid-producing bacteria.
In 1945, Grand Rapids in Michigan became the first city in the world to fluoridate its water. Over a 15-year span, health researchers tracked the tooth decay rate among Grand Rapids' nearly 30,000 school children and found that the rate dropped more than 60%. This was a major scientific breakthrough because it firmly demonstrated that decay was a preventable disease.
In the 1950s and 1960s, thousands of U.S. communities began fluoridating their drinking water and their tooth decay rates dropped significantly. Today, even in an era when fluoride toothpaste is widely used, the Centres for Disease Control and Prevention report that fluoridated water reduces tooth decay by 25% over a lifetime.
Fluoride and fluoridation are among the most thoroughly researched topics of the past 75 years. And the research continues to grow. Over the past five years, studies of children have confirmed fluoridation’s crucial role in reducing tooth decay and concluded that “Water fluoridation is a safe and effective public health measure.”
Fluoride Today
Today, fluoride is widely acknowledged as a way to prevent cavities and we suggest buying fluoridated toothpaste to get your daily dose of cavity-preventing fluoride.
This is the main mechanism by which fluoride exerts its anticaries benefits. It has been established that hydroxyapatite starts to dissolve when pH drops below 5.5, and fluorapatite starts to dissolve when the pH drops below 4.5. If biofilm pH is lower than 5.5 but higher than about 4.5 and flouride is available in low concentrations, fluorapatite forms on the surface layers of enamel even if hydroxyapatite dissolves in the subsurface enamel. The overall effect is reduced dental demineralization, thanks to the protective outer layer of fluorapatite. When oral pH normalizes after an acid attack and rises again above 5.5, fluoride enhances enamel–dentin remineralization. If flouride is no longer available, the oral environment begins to favor demineralization if the pH falls below 5.5.
Fluoride ions inhibit the bacterial enzyme enolase, which interferes with the production of phosphoenolpyruvate (PEP). PEP is a bacterial source of energy and a molecule that is necessary for the uptake of sugar, which provides bacterial nutrition. A dental biofilm that contains just 1 ppm to 5 ppm of fluoride (an amount that is reached by using fluoridated toothpaste) is found to inhibit the adhesion, growth, metabolism, and multiplication of caries-linked oral streptococci. The presence of higher concentrations of fluoride—10 ppm to 100 ppm, which can be attained after use of prescription fluoride preparations—has also been found to inhibit acid production by most plaque bacteria.
Exposure to an abnormally high concentration of fluoride during the early stages of tooth development or childhood can lead to hypomineralization of the tooth’s enamel and increased porosity that is reflected in the opacity of enamel as chalky white lines or and streaks, but more advanced forms are marked by brown and black stains and enamel erosion.
In general, teeth with more severe dental fluorosis have significantly higher levels of fluoride in enamel than those with less severe forms of dental fluorosis. Also, the extent and degree of hypomineralization increases with increased fluoride exposure during development. In cases of severe hypomineralization, porous enamel appears brown and it can be very fragile, with surface damage occurring quite easily during chewing, attrition, and abrasion.
Indian Dental Association (IDA) recommends that children and adults use fluoride toothpaste displaying the IDA Seal of Acceptance. For children younger than 3 years, caregivers should begin brushing their children’s teeth as soon as they start to appear in the mouth by using water on a toothbrush and begin using toothpaste once the child is able to spit effectively.
A primary method of fluoride delivery is systemic, being artificially provided in water, milk, salt, or supplements, which must be ingested to be able to have any effect on teeth. In all of these applications, the primary action of fluoride in promoting remineralization and reducing demineralization is due to the presence of fluoride in a beneficial amount and at the right time. What follows is a brief discussion of the main forms of systemic fluoride delivery employed by dental professionals worldwide today:
Water Fluoridation – Water fluoridation is the primary systemic method of fluoride delivery to the population. Fluoride occurs naturally in water supplies, usually at very low concentrations of 0.1 ppm. Community water studies have uncovered a few key findings: Overall, there is a 50% reduction in dental caries rates among children with 1 ppm fluoride in the community drinking water. However, this caries protection occurs only with consistent fluoride exposure. This is evident in studies that found that children who move to a non-fluoridated water community experience an increase in caries rates. In addition, adults also benefit from fluoride, with reduced coronal and root caries rates among those residing in fluoridated water communities.
Salt Fluoridation – This is a method of fluoride delivery used primarily in Europe, as well as Costa Rica, Columbia, and Jamaica. A landmark Swiss study found that fluoridating table salt reduced children’s caries levels by 50% over a 10-year period. But there are concerns about excessive fluoride intake and the emergence of dental fluorosis, as well as concerns about increased salt intake.
Milk Fluoridation – Adding fluoride to liquid, powdered, and long-life milk has been implemented in Eastern Europe, China, the UK, and South America. It has the advantage over water fluoridation in that it can be targeted directly at certain segments of the population, and intake can be controlled. However, well-controlled studies have not yet been conducted.
Fluoride Supplements – Indian Dental Association (IDA) currently recommend that oral fluoride supplements be used only in high-risk children residing in nonfluoridated areas.
Table 1. Recommended Supplemental Fluoride Dosage Schedule.
| Age of child | Less than 0.3 ppm water fluoride concentration | 0.3 ppm to 0.6 ppm water fluoride concentration | Greater than 0.6 ppm water fluoride concentration |
|---|---|---|---|
| Birth to 6 months | 0 | 0 | 0 |
| 3 years | 0.25 mg liquid drops | 0 | 0 |
| 3 to 6 years | 0.5 mg drops or tabs | 0.25 mg | 0 |
| 6 to 16 years | 1 mg | 0.5 mg | 0 |
Another main method of fluoride delivery is topical, in the form of toothpastes, gels, varnishes, paint-on formulations, and mouth rinses that come into contact with the surface of the tooth.
Toothpaste has come a long way from its beginnings. The first clinically proven fluoride toothpaste was introduced in 1955 by Crest; it contained 0.4% stannous fluoride (SnF2). Each decade after that brought further advancements: In the 1960s, gel products hit the markets; in the 1970s antiplaque claims were introduced; tartar control products were first marketed in the 1980s; and the 1990s were marked by specialty products on the market, such as antigingivitis, whitening agents, and changes in the type of container used to deliver the dentifrice, such as pumps and dual chambers.
Today, most over-the-counter products contain between 850 ppm to 1150 ppm fluoride. Clinical trials indicate a dose-dependent relationship between fluoride concentration and caries prevention, with a 6% increase in efficacy and 8.6% reduction in caries for every 500 ppm fluoride increase. Research has documented that a regular low-dose source of fluoride is the most efficient means to prevent demineralization of teeth and to enhance remineralization. Fluoride becomes incorporated with the enamel apatite crystal, rendering the enamel more resistant to acid dissolution. Fluoride in saliva and plaque also promotes remineralization. And finally, fluoride also has a modest antimicrobial effect on plaque bacteria, with stannous fluoride being particularly effective against Streptococcus mutans.
There are also prescription fluoridated gels that contain 5000 ppm fluoride that are intended for limited use in high caries risk patients.
Fluoride concentration is the important determinant of anticaries efficacy. Therefore, using more toothpaste than is recommended (such as a pea-sized amount for children) does not provide more caries protection.
Brushing behavior is also important: Brushing twice a day is linked to a 20% to 30% lower likelihood of caries compared to brushing once or less daily. It should be noted that brushing frequency is linked to socioeconomic status, with children in poorer families brushing less, and this being one reason they experience more caries. Data shows that brushing immediately before bed plays an important role in reducing plaque load in the oral environment during sleep, when salivary flow and buffering capacity are naturally reduced. Therefore, the recommendation to brush just before going to bed and at least one other time during the day before or after a mealtime is appropriate for most patients. Fluoridated toothpaste can also be used therapeutically by asking the patient to apply a dab of paste with a finger or brush directly to a cleaned active lesion immediately before going to bed. This also allows an increased concentration of fluoride in the vicinity of the lesion at a time of day when salivary output is naturally low.
Rinsing behavior is another determinant of anticaries efficacy. People who use a cup to rinse with water after brushing have approximately 20% more caries than those who use the toothbrush or hand to collect water. This is because more fluoride is washed away when rinsing with a cup of water after brushing.
Early commencement of tooth brushing has been associated with lack of colonization by the bacteria that are primarily responsible for cavities. Because young children tend to swallow toothpaste when they are brushing, which may increase their exposure to fluoride, the following guidelines have been established by Indian Dental Association (IDA) to moderate their risk of developing dental fluorosis while optimizing the benefits of fluoride.
Children from birth to 3 years of age should have their teeth and gums brushed by an adult. The use of fluoridated toothpaste in this age group is determined by the level of risk. Parents should consult a dental professional to determine whether a child up to 3 years of age is at risk of developing tooth decay. If such a risk exists, the child’s teeth should be brushed by an adult using a minimal amount (a portion the size of a grain of rice) of fluoridated toothpaste. Use of fluoridated toothpaste in a small amount has been determined to achieve a balance between the benefits of fluoride and the risk of developing fluorosis. If the child is not considered to be at risk, the teeth should be brushed by an adult using a toothbrush moistened only with water.
Early childhood tooth decay can be painful, may cause infection and is difficult and expensive to treat. Therefore, by a child’s first birthday, the parents should consult a health professional knowledgeable in the areas of early childhood tooth decay and the benefits of fluoride. This health professional will help to determine the child’s risk of developing tooth decay and whether there would be a benefit of brushing with a minimal amount (a portion the size of a grain of rice) of fluoridated toothpaste before the age of 3 years.
A child may be at risk of early childhood tooth decay if one or more of the following conditions exist:
Toothpastes and gels also contain abrasives (such as hydrated silica) to clean teeth; binders (such as xanthan gum, carrageenan or carbopol) to prevent the separation of ingredients; coloring for visual appeal; humectants (such as glycerin or sorbitol) to retain moisture; buffers (such as phosphates) to maintain product stability; flavorings (such as peppermint and cinnamon); and surfactants (such as sodium lauryl sulfate) to produce a foaming action and reduce surface tension.
What is needed is plaque and gingivitis protection, tartar control, whitening, sensitivity protection, erosion protection and protection from oral malodor. Many fluoride dentifrices today cover some combinations or all of these benefit areas in one dentifrice.
Mouthwashes have also been formulated with acidulated phosphate fluoride, stannous fluoride, ammonium fluoride, and amine fluoride, although some of these come with precautions. For example, stannous fluoride rinses have been associated with discoloration of teeth and tooth restorations, and acidulate phosphate fluoride is contraindicated in people with porcelain or composite restorations because it can cause pitting or etching.
Many of the fluoride mouth washes on the market internationally also contain antimicrobial ingredients. These include chlorhexidine, cetylpyridinium chloride, triclosan, delmopinol, hexetidine, and Sanguinaria extract.
Typically, it is recommended that 10 ml of the mouth rinse solution be swirled around
in the mouth for 1 minute. The benefit of daily rinsing is marginally greater than
weekly rinsing but not statistically significant. Overall, fluoride mouth rinses
are considered beneficial from a public health perspective only if groups of people
at high risk of caries are being targeted, since they are not cost-effective in
a population with a low incidence of disease.
Fluoride mouth rinses are an effective preventive measure for at risk individuals
and should be used according to the specific needs of the individual. Fluoride mouth
rinsing is not recommended for children under 6 years of age.
Mouthwash with fluoride can help make your teeth more resistant to decay, but children six years or younger should not use it unless it’s been recommended by a dentist. Many children younger than 6 are more likely to swallow it than spit it out because their swallowing reflexes aren’t fully developed.
IDA recognizes and supports the professional topical applications of fluoride gels, foams and varnishes in the prevention of dental caries for high-risk individuals and to increase the resistance of the teeth against dental caries and when appropriate dental care measures (such as good oral hygiene or the use of a fluoride toothpaste) are not working or are not being followed. The dentist may also suggest the use of fluoride supplements, particularly in areas where water fluoridation isn’t practiced.
These contain higher concentrations of fluoride than products sold over the counter for home use. They typically contain 5,000 ppm to 12,300 ppm and are applied only in the dental office. They are generally recommended for use twice yearly, although in severe cases, they may be applied more frequently. Significant reductions in dental caries—as much as 41%—have been seen when applied in this way. However, no benefit has been seen with the use of single applications or infrequent applications.
These contain a high level of fluoride (22,600 ppm) and are applied only in a dentist’s office. Varnishes are used to deliver fluoride to specific sites or surfaces within the mouth and are typically applied every 3 months or 6 months. The correct application of a fluoride varnish has been linked with a 38% reduction in dental caries. Varnishes are designed to harden on the tooth, forming a deposit of calcium fluoride that can act as a reservoir for the slow release of fluoride over time.
Fluoride is an effective therapeutic and preventive agent for dental caries. The mineral alters the caries process by interfering with the dynamic of lesion development by enhancing remineralization, reducing demineralization, and inhibiting bacteria. While there are many forms of fluoride delivery, the incorporation of fluoride in a dentifrice has proven to be one of the most effective prevention and intervention strategies for dental caries. It should be noted that although fluoride therapy is important for caries control, it does not always stop caries development and progression. The tried-and-true public health recommendations of proper oral hygiene, such as brushing teeth at least twice a day, flossing to clean in between teeth, and cutting back on dietary sugar intake, continue to be very important in fighting caries.
Dental flourosis is a developmental disturbance of enamel which occurs during enamel forming. It is caused by systemic overexposure to fluoride during the first six years of life, when the enamel of the crowns of permanent teeth is formed. The enamel contains more protein, is porous, opaque and less transparent. Clinical manifestation vary from (quantitative) narrow, white horizontally running lines, larger patches or yellow to light brown colored areas of porous enamel, to (qualitative) loss of enamel in varying degrees. For the optimal effect of fluoride toothpaste, it is important to follow recommended guidelines for the use of products containing fluoride. In this way, the probability for flourosis is decreased and the protective effect of fluoride on the development of caries is significantly important.
Just like any other substance we are exposed to in our everyday lives (oxygen, water, table salt), fluoride can be toxic in certain quantities. Acute toxicity can occur after ingesting one or more doses of fluoride over a short time period which then leads to poisoning. The stomach is the first organ that is affected. First signs and symptoms are nausea, abdominal pain, bloody vomiting and diarrhea. This is followed by a collapse with paleness, weakness, shallow breathing, weak heart sounds, wet, cold skin, cyanosis, dilated pupils, hypocalcaemia and hyperkalemia, and in to two to four hours even death. Other possible effects include muscle paralysis, carpopedal spasms and extremity spasms. Based on research papers and some overdose cases, the probable toxic dose (PTD) was defined at 5 mg/kg of body mass. The PTD is the minimal dose that could trigger serious and life-threatening signs and symptoms and requires immediate treatment and hospitalization. Example: PTD in a 20 kg child would be achieved at ingesting 100g (75 ml) of toothpaste which contains 1000-1500 ppm of fluorides or 100 pills, that contain flourides (0,5-1 mg fluoride).
Despite the widespread presence of fluoride in our life and the seriousness of the conditions associated with its toxicity, the number of cases of acute toxicity today, compared to the first half of twenty first century, is very rare. At that time, sodium flouride was used as a pesticide and rat poison. Because of its appearance it was often mistaken for flour, powdered sugar or any other white powder product, which is used in the kitchen. Today, poisoning is mainly due to unsupervised ingestion of products for dental and oral hygiene and over-flouridated water.
Flourosis is endemic in 22 countries. Continent of Asia is the worst affected, with India and China as the worst affected nations. Other regions include Mexico, Argentina, east and north Africa etc. It was possible to eradicate skeletal flourosis in USA long ago by changing to a water source with low fluoride.
1 lakh+ villages, with more than 10 million people, stand to face disability and other serious health problems because of high Flouride in their water across 22 States and 200+ districts of India. Throughout India flourosis is essentially Hydroflourosis except in parts of Gujarat and U.P. where industrial flourosis is also seen.
Rajasthan has the maximum number of Flouride affected areas (pinks are high Flouride points between 1 ppm-3 ppm, Blue for 3 ppm to 5 ppm and Green for greater than 5 ppm.
Andhra Pradesh-Telangana has highly Fluoride affected places such as Nalgonda and Prakasam.
Karnataka with increasing Borewells is rising as a highly Fluoride affected state. Maharashtra with Basalt rocks presents a unique Fluoride situation.
Gujarat has some of the oldest Fluoride affected places of Mehsana and Amreli. Madhya Pradesh presents a challenging mix of Fluoride and malnutrition in Jhabua,Dhar and Chhindwara among other places.
Bihar has rising number of Fluoride affected places — Jamui, Gaya, Munger. Fluoride affected West Bengal areas are mostly in the eastern regions bordering Jharkhand.
Haryana has a moderate to high fluoride problem very close to Delhi. Tamil Nadu has high fluoride in the northern districts. of Krishnagiri and Dharmapuri but also in other places because of the geology:
Assam has a long fluoride history with Karbi Anglong, Nagaon highly affected and the capital Guwahati recently showing high concentrations. Punjab like Haryana has a moderate range of high fluoride problem, but areas bordering Rajasthan show greater concentrations.
Chhattisgarh has high fluoride affected districts such as Korba and Durg. Kerala with Alapuzha and Pallakad has two areas with high fluoride:
From Agra to Unnao to Sonbhadra, Uttar Pradesh has hundreds of habitations with high Fluoride.
In worst affected states, maps have been prepared of geographic pathology on the basis of fluoride distribution in the drinking water.
70-100% districts are affected in Andhra Pradesh, Gujarat and Rajasthan.
40-70% districts are affected in Bihar, National Capital Territory of Delhi, Haryana, Jharkhand, Karnataka, Maharashtra, Madhya Pradesh, Orissa, Tamil Nadu and Uttar Pradesh
10-40% districts are affected in Assam, Jammu & Kashmir, Kerela, Chattisgarh and West Bengal. While the endemicity for the rest of the states is not known.
Gujarat:1.5 - 18.0 mg/L; Andhra Pradesh: 0.4 - 29.0 mg/L; Assam : 1.6 - 23.4 mg/L; Bihar: 0.2 - 8.32 mg/L; Chattisgarh: information awaited; Delhi:0.2 - 32.0 mg/L; Haryana: 0.2 - 8.32 mg/L; Jammu & Kashmir 0.5 -4.21 mg/L; Jharkhand 0.5 - 14.32 mg/L; Karnataka: 0.2 - 7.79 mg/L;
| Andhra Pradesh(16): |
The total number of districts endemic for Fluoride / Fluorosis are: • Cuddapah • Hyderabad • Krishna • Medak • Warangal • Ananthapur •Karimnagar •Kurnool • Nalgonda • Prakasam • Chittoor • Guntur • Khammam • Mahbubnagar • Nellore • Rangareddy |
| Assam (2): |
The total number of districts endemic for Fluoride / Fluorosis are: • Karbi Anglong • Nagaon |
| Bihar (6): |
The total number of districts endemic for Fluoride / Fluorosis are: •
Rohtas • Gaya • Nawada
|
| Chhattisgarh (2): |
The total number of district endemic for Fluoride / Fluorosis are: • Durg • Dhandewala |
| Delhi (7): |
The total number of Zones endemic for Fluoride / Fluorosis are: •
West Zone • North West Zone
|
| Gujarat (24): |
The total number of districts endemic for Fluoride / Fluorosis are: •
Ahmedabad • Amreli • Anand
|
| Haryana (12): |
The total number of districts endemic for Fluoride / Fluorosis are: •
Rewari • Faridabad • Karnal
|
| Jammu & Kashmir (1): |
The district endemic for Fluoride / Fluorosis is: • Doda |
| Jharkhand (5): |
The total number of districts endemic for Fluoride / Fluorosis are: •
Deoghar• Pakur • Palamu
|
| Karnataka (16): |
The total number of districts endemic for Fluoride / Fluorosis are: •
Dharwad • Gadag • Bellary
|
| Kerala (3): |
The total number of districts endemic for Fluoride / Fluorosis are: •
Palghat • Alleppy
|
| Madhya Pradesh(14): |
The total number of districts endemic for Fluoride / Fluorosis are: •
Shivpuri • Jubua • Mandla
|
| Maharashtra (10): |
The total number of districts endemic for Fluoride / Fluorosis are: •
Bhandara • Chanderpur |
| Orissa (18): |
The total number of districts endemic for Fluoride / Fluorosis are: •
Angul • Dhankanal • Boudh |
| Punjab (17): |
The total number of districts endemic for Fluoride / Fluorosis are: •
Mansa • Faridkot • Bhatinda |
| Rajasthan (32): |
The total number of districts endemic for Fluoride / Fluorosis are: •
Bhilwara • Ajmer • Sirohi |
| Tamil Nadu (9): |
The total number of districts endemic for Fluoride / Fluorosis are:
•
Krishnagir • Dharmapuri
|
| Uttar Pradesh(7): |
The total number of districts endemic for Fluoride / Fluorosis are: •
Varanasi • Kaunauj |
| West Bengal (7): |
The total number of districts endemic for Fluoride / Fluorosis are: •
Birbaum • Bankura • Malda |
