Caries Prophylaxis with Fluorides

In addition to a tooth-healthy diet and adequate oral hygiene, fluorides are the mainstay of caries prophylaxis (prevention of tooth decay). Fluoride is a natural trace element. It occurs worldwide in the soil and in all water, including drinking water. A particularly high fluoride content is found in seawater and volcanic soils. In the human organism ossification (formation of bone tissue) takes place only in the presence of fluoride. Fluoride is also indispensable for the formation of the resistant, poorly soluble mixed crystals of hydroxyapatite and fluorapatite in the dentin (tooth bone) and enamel of the hard tooth substance. The great success of fluorides in dentistry is based on the fact that – unlike tooth-healthy nutrition and oral hygiene training – no change in behavior is required. This is because, simply by being present in the aqueous oral environment, fluorides are caries-protective (protective against tooth decay) in multiple ways:

  • They promote remineralization (re-storage of minerals from the saliva into the tooth structure).
  • They inhibit demineralization (dissolution of minerals from the tooth surface in acidic oral environment).
  • They form a calcium fluoride top layer, which acts as a fluoride depot and when exposed to acid (food acids or acids from bacterial metabolism) fluoride is released to the tooth surface for remineralization
  • They are incorporated into the crystal structure of the tooth structure: hydroxide ions (OHˉ) in the apatite crystal are partially replaced by fluoride ions (Fˉ), which makes the crystal structure more difficult to dissolve acid and experiences an increase in hardness
  • They make it more difficult for bacteria to adhere (adhere) to the tooth surface and thus contribute to plaque reduction (reduced formation of microbial plaque)
  • They inhibit bacterial enzymes (especially enolase), which are necessary for the breakdown of sugar. This inhibition of bacterial metabolism leads to the production of fewer acids, which ultimately attack the tooth structure.

Since all the above mechanisms of action are effective when the fluoride is in direct contact with the tooth surface, local fluoride application has become established in dentistry. Systemic fluoride administration, which is provided to the entire organism via drinking water, mineral water, food, table salt or tablets, ultimately also act by the fluoride after absorption via the digestive tract, distribution in the organism via the blood plasma and release via the saliva back into the oral environment to act directly caries-protective (protective against tooth decay) on the tooth structure.

Safety of fluoride application

Age-dependent fluoride supplementation of 0.25 mg to 1.0 mg daily is now considered absolutely safe from a general medical point of view. One prerequisite is that fluoride, especially in the first years of life, be administered only under supervision and after a fluoride history has been carefully obtained. Otherwise, side effects are to be expected:

Enamel fluorosis (synonyms: dental fluorosis, mottled enamel, mottled teeth, mottled enamel): is the first and most common side effect. If too much fluoride is ingested during the enamel formation phase, which extends over the first eight years of life, the ameloblasts (enamel-forming cells) of all things react sensitively to the excess supply. The result is a qualitatively poorer enamel structure that, in contrast to the properly formed enamel, appears opaque (less translucent) and exhibits white to brownish spots or streaks. In elderly people who have been supplied with drinking water containing 8 ppm fluoride or more throughout their lives, densification of the bone structure is observed. In areas of the world that have drinking water with a fluoride content of 20 ppm or more (India, South Africa) or where, due to the climate, a lot of water of even lower fluoride content must be drunk, the disease of skeletal fluorosis (synonym: bone fluorosis) occurs: the compacted and hardened bones with a thickened cortical (outer layer of bone) lack elasticity and resistance. The joints and spine also suffer from bone proliferation, so that stiffening is the result.

Indications (areas of application)

Fluoridation of tooth surfaces to protect against caries is in principle indicated for anyone who cannot consistently eat a healthy diet and maintain optimal oral hygiene.In order to avoid overdoses, the recommendations must be preceded by a so-called fluoride anamnesis, which takes several factors into account. In addition, the fluoride doses for children must be graduated according to age. Fluoride history:

  • Dietary habits: Foods generally contain very little fluoride (exceptions: Tea varieties (green and black tea) depending on the area of cultivation, skin and bones of sea fish, separator meat).
  • Drinking water: our drinking water basically has small traces of fluoride. The fluoride content is to be asked at the respective waterworks.
  • Mineral water: is a source of fluoride not to be underestimated. Corresponding information can be found on the bottles and must be considered in the fluoride recommendation.
  • Fluoride gifts in the form of tablets
  • Table salt: fluoride-added table salt has now become widely available.

Fluoride basic prophylaxis:

If the caries risk is not increased and there are no special features in the fluoride anamnesis, a fluoride basic prophylaxis is recommended. This consists of the age-dependent use of a fluoride toothpaste and fluoridated table salt. Further fluoride doses are not usually necessary. The preventive effect is increased by applying the toothpaste (at least) twice a day. Increased caries risk:

In case of increased caries risk, basic prophylaxis should be supplemented by:

  • Daily mouth rinses with fluoride-containing solutions (250 to 500 ppm) or once-weekly brushing of gels (fluoride content 12,500 ppm): both applications should be made only from school age, when it is certain that the child can safely master spitting and rinsing and that the fluoride preparation is not swallowed down
  • Professional application of varnishes (fluoride varnish), gels (fluoride gel) or touch-ups two to four times a year at the dentist’s office
  • Fluoride tablets

Children:

  • From the eruption of the first milk teeth, so from the age of about six months, parents are recommended to clean the milk teeth once a day with a maximum pea-sized amount of fluoride-containing children’s toothpaste (max. 500 ppm, 500 parts per million).
    • Children under 6 years of age are recommended to use a toothpaste with reduced fluoride concentration (500 ppm) (mean caries reduction of 24%).
  • For children two years and older, cleaning is also done twice a day with a pea-sized amount of children’s toothpaste. The children can brush independently only after learning to write. Until then, parents must consistently clean daily.
  • Toothpastes with flavors (fruit, candy or similar) provide incentive to swallow and should therefore not be used.
  • From school age, children as well as adults should brush at least twice a day with junior or adult toothpaste, which both have a fluoride content of 1,000 to 1,500 ppm (parts per million).
  • In addition to fluoridated toothpaste, food may also be prepared for children with fluoridated table salt, as this can not be overdosed practically. Here, the focus is on the local effect of fluoride on the tooth surface during chewing.

Contraindications

Contraindications to fluoride supplementation (fluoride supplementation) are derived from the fluoride history in conjunction with age-based dosing recommendations.

Procedures

I. Systemic fluoridationI.1. Drinking water:Systematic enrichment of drinking water with fluoride does not take place in Germany, unlike in some other countries. Worldwide, about 320 million people are connected to a drinking water supply with 1 mg fluoride per liter. However, even our drinking water basically has small traces of fluoride, which vary depending on the area. 90% of German drinking water has a fluoride content of less than 0.25 mg per liter. Only about 1 % contains more than 0.5 mg. This makes drinking water a negligible source of fluoride for the vast majority of the German population. The exact value can be obtained from the respective waterworks. I.2 Mineral water: Attention! Some mineral waters contain more than 1 ppm (mg/l) fluoride. According to the Mineral and Table Water Ordinance, a fluoride content of more than 1.5 ppm (mg / l) must be labeled as “containing fluoride”. Above 5 ppm, a warning label is mandatory. I.3. salt fluoridation: The use of fluoride salt in the household serves as basic prophylaxis.The addition of fluoride in table salt makes caries prophylaxis (prevention of tooth decay) available to people who are not reached by other preventive measures. Salt fluoridation is a very cost-effective and broad-based preventive measure, which, in addition to the systemic effect (distribution throughout the organism), also has a great local effect (acting directly on the tooth substance), as the food has contact with the tooth surfaces for a longer period of time during the chewing process. In addition, the fluoride dosage is so minimal (250 mg/kg, 250 ppm) that it is toxicologically safe and overdose is not possible. I.3. fluoride tablets: are recommended in case of high caries risk. In order to achieve the highest possible local effect on the teeth even with this systemic administration, the tablets should be sucked slowly or, in children, for example, dissolved in a drop of water to a pulpy consistency, offered on a spoon.The recommended fluoride dosage depends on age and the fluoride content of drinking water:

Age Fluoride concentration in drinking/mineral water
< 0.3 mg / l 0.3-0.7 mg / l > 0.7 mg / l
< 6 months
6-12 months 0.25 mg
1-3 years 0.25 mg
3-6 years 0.50 mg 0.25 mg
> 6 years 1.00 mg 0.50 mg

In general, the risk of overdose is greater with systemic fluoride administrations (acting through the organism) than with locally applied fluorides. This leads to the principle: to prevent the risk of overdose, do not combine multiple systemic fluoride administrations – i.e., supplement fluoride salt or fluoride-rich mineral water or fluoride tablets. II. Local fluoridation

Principle: a local fluoridation measure (acting directly on the tooth surface) can be combined with other local measures. II.1 Fluoridated toothpaste: its use serves as basic prophylaxis against caries. For children up to school age, children’s toothpastes with a reduced fluoride content (max. 500 ppm, 500 parts per million) are recommended so that even regular swallowing does not pose a risk of overdosage. Around the age of six, children should switch to a junior or adult toothpaste with a fluoride content of 1,000 to 1,500 ppm. II.2 Mouth rinses: In general, daily rinses with a fluoride-containing solution (250 ppm to 500 ppm) are an effective, because regular, caries prophylactic measure in cases of increased caries risk, but require daily readiness for this. They may only be used by children when they have mastered rinsing and spitting out safely (at around six years of age). II.3 Gels: Higher-dose fluoride gels (12,500 ppm), which are brushed in once a week at home, accordingly require less effort than daily rinsing solutions – but they are also more easily forgotten. Gels are also not indicated for preschool-aged children.For school-aged children and older, gels can be used independently of existing basic fluoridation measures (e.g., fluoride toothpaste). Note: Fluoride concentrations of 12,500 ppm must not be used in younger children! II.4. varnishes and touch-ups: the high-dose preparations are reserved for professional use in the dental office and are applied (applied) two to four times a year depending on the caries risk.

Benefits

You significantly reduce your individual caries risk through the regular use of fluorides, thus offering your teeth protection that ideally prevents caries growth altogether in conjunction with adequate oral hygiene and tooth-healthy dietary habits. In this way, you can keep your teeth healthy and vital well into old age. Guideline

  1. S2k guideline: fluoridation measures for caries prophylaxis. (AWMF register number: 083-001, January 2013 long version.
  2. S2k guideline: caries prophylaxis in permanent teeth – basic recommendations.(AWMF Register Number: 083-021, June 2016 Abstract Long version.