What is Fluoride

What is Fluoride?

Fluoride is a mineral that occurs naturally in rocks, soils and in water. Small amounts are present in almost all foods. In humans, it is a natural constituent of tooth enamel.

Sources and Benefits of Fluoride

There are numerous studies concerning the relationship of fluoride intake and decreased caries. The beneficial effects of fluoride can be systemic or topical.

Systemic Fluoride

Water fluoridation: Water fluoridated at a concentration ranging from 0.5-1.2mg/l, gives a caries reduction of 50%. The concentration depends on geographic variations to adjust to the consumption of water.

Fluoridated salt: Fluoridated salt at 200-250 ppm is as effective as water fluoridation and is an alternative where water fluoridation is not feasible, due to technical and financial problems. 

Fluoridated milk: This has been successful in some countries like Bulgaria, but is limited to school children and has problems with distribution and storage. 

Fluoride supplements (drops and tablets):  The dosage depends on the fluoride concentration in the drinking water. It has limited application as a public health measure.

 

Topical Fluoride

Professionally applied fluorides: A wide variety of solutions and gels are available at a concentration of 12,300ppm. These are used as a prophylactic measure to prevent caries and have been found to reduce decay by about 30%.

Mouth rinses: Many mouth rinses are available for home use, at a concentration of 100ppm for daily use or 1000ppm for weekly use by high-risk patients, with caries reductions of about 30%. Mouth rinses are contraindicated in children below 7 years of age. 

Toothpastes: The international standard for fluoridated toothpastes is 1000-1100 ppm of fluoride as either 0.76% sodium monofluorophosphate or 0.25% sodium fluoride. It has been reported to reduce caries by 50%.

Mechanism of Fluoride

At least four modes of action are thought to occur:

·       Remineralisation of early carious lesions: Presence of fluoride has been shown to promote the process of remineralisation and the healed site is more resistant to caries attack.

·       Reduction in acid solubility of enamel: It inhibits demineralisation by lowering the critical pH for the dissolution of enamel.

·   Increase in the rate of post-eruptive enamel maturation: It involves the incorporation of fluoride into the enamel during enamel formation.  The hydroxyl ion is substituted by the fluoride ion in the hydroxyapatite leading to the formation of larger fluorapatite crystals, which are less susceptible to acid dissolution.

·       Inhibition of acid formation by plaque bacteria: Fluoride interrupts the metabolic cycle of the oral pathogenic bacteria, thus reducing their ability to metabolise the sugars and produce the acids, which cause dental caries.

Fluoride Safety

Like any other chemicals, fluoride can have undesirable effects and even be toxic, if consumed in excess.

Dental Fluorosis

Fluorosis or mottling occurs due to long-term excess of fluoride and occurs in areas where there is high level of fluoride occurring naturally in water. Clinically, it can vary from faint white opacities to severe pitting and discolouration. With the use of standard concentration  (1000-1100 ppm F) fluoride toothpaste by young children below six years of age, there is a potential risk of dental fluorosis, when eaten or swallowed.  However, the prevalence of dental fluorosis is reported to be low in countries where there is water fluoridation and several other fluoride sources like fluoridated infant formulas. More importantly, the reported levels of fluorosis are mainly in the mild to moderate classification and therefore do not present as a public health problem Considering the situation in Nepal, where fluoride level is low guidelines for use of fluoridated toothpaste by children below six years of age should, therefore, need not be the same.

Sstemic Effects

There have been conflicting information about the risks and benefits of fluorides in the press and scientific literature, with claims that fluorides cause or contribute to cancer, skeletal fluorosis, Down’s Syndrome, renal diseases etc. However, thorough studies and reviews clearly indicate that there is no evidence of such adverse health effects due to appropriate concentration of fluoride.

Lack of Fluoride in Nepal

Due to its geographic proximity to India, Nepal was thought to have too much fluoride naturally occurring in the ground water.  In some parts of India, such as Rajasthan, Haryana, Uttar Pradesh, and Andhra Pradesh, the natural level of fluoride ion in the drinking water is excessive. However, a three-year nation-wide study by the UMN Oral Health Programme has determined that the fluoride levels in the water supplies throughout Nepal have low levels of fluoride, which is insufficient to prevent caries.

 Feasibility of Fluoride Vehicles in Nepal

Provided that a community has a piped water supply, water fluoridation is the most effective and socially equitable method of reaching the whole population. In Nepal, however, this is not possible due to its poor infrastructure. Where water fluoridation is not feasible, salt fluoridation is an alternative, which has proved to be as effective as water fluoridation in inhibiting caries in both deciduous and permanent teeth. This has often been suggested, but not taken up further due to distribution problems. With the establishment of salt iodination plants in Nepal and The Salt Trading Corporation as the only agent responsible for the distribution and sale of salt, fluoride could be added to the iodised salt at the same plant, making salt fluoridation a very cost-effective national heath strategy.

Milk fluoridation is yet another suggestion but not a promising technology for Nepal since packaged milk is only accessible to a very small minority of the population. Many villagers obtain milk from their own cows and buffaloes. Thus, the present situation makes use of affordable fluoridated toothpaste by the whole population the most important strategy for keeping the caries levels low and thereby improving the oral health in Nepal. The main advantage is that toothbrushing is a routine part of personal hygiene and the only change required is to use fluoridated toothpaste instead of a non-fluoridated one. By working together with the manufacturing sector, dental organisations, professionals and community members like teachers, the use of fluoridates toothpastes can be widely promoted.