The importance of fluoride in caries prevention is supported by an extensive scientific literature and is recognized by the world health organization and the Italian health ministry.
Caries is an infectious disease due to bacteria that metabolize the sugars present in the oral cavity, producing corrosive acids against the enamel and the underlying dentin. Because of the acids the enamel is deprived of its mineral component, formed essentially by calcium and phosphorus but also by fluorine. The latter is found naturally in saliva and derives from food supplies, which must cover a daily requirement of 1.5-4 mg in the adult population.
Fluorine helps prevent tooth decay by slowing the destruction of the enamel and accelerating the remineralization process. More precisely, its preventive function is expressed through the following mechanisms:
- Fluorapatite formation: it is a variant of hydroxyapatite that normally constitutes tooth enamel, in which fluoride replaces hydrogen ions forming a material more resistant to demineralization and attack by acids and bacterial plaque. The synthesis of fluorapatite occurs during the formation of the dental structure (amelogenesis), which underlines the importance of fluoride in children's diet and oral hygiene;
- Enamel remineralization: on the already erupted teeth the fluorine has the ability to fix itself in the most external layer of the enamel, together with the dissociated calcium and phosphate, always in the form of fluorapatite, compensating the height eroded by the plaque acids;
- Antibacterial action: fluorine is able to counteract the adhesion of Streptococcus mutans (main responsible for caries) to oral tissues.
One of the main sources of fluoride is represented by drinking water, but in this regard there is a wide variability between the different sources. With the exception of some volcanic waters, such as those found in some areas of Campania and Lazio, in Italy most of the drinking water contains a quantity of fluorine ions not sufficient to guarantee a protective effect against caries. On the site //www.acqueitaliane.org/ the content of the fluorine ion, expressed in mg / l, can be found in the most common mineral waters available in Italy.
From these premises derives the importance of integrating fluorine heritage topically and / or systemically:
- topically through the use of all those dispensing means that supply fluorine in high concentrations directly to the exposed surfaces; the most characteristic example is given by fluorinated toothpastes or mouth rinses, but it is also possible to periodically apply fluorinated gels to the teeth;
- systemically through oral administration of fluoride in drops or tablets.
The method of preventing dental caries by fluoride, topically or systemically, is called fluoroprophylaxis .
To date, the general orientation is to consider the preventive effect obtained by way of topical administration after the eruption of the teeth to be more effective (and undoubtedly safer).
We have mentioned about the importance of fluoride in children. However, up to 3-6 years of age there is a rather important danger called dental fluorosis, deriving from the involuntary intake of excessive amounts of fluoride. Children affected by fluorosis have alterations in the color of their teeth, in particular permanent incisors, up to real dental hypoplasias in the most serious cases.
The most frequent cause of fluorosis is the ingestion by the child of the toothpaste used for tooth brushing. For this reason the orientation of many dentists is to:
- avoid using toothpaste in tooth brushing in the first year of life;
- between the first and the sixth year of age use minimum quantities (the size of a pea) of standard fluoride toothpaste (1000 ppm) twice a day, or use a low fluoride content (500ppm) twice a day ;
- after 6 years you can start using toothpastes with a higher fluorine content (at least 1000 ppm);
- in high-risk caries children, professional topical fluoride application can be considered every 3-6 months.
In adults at risk of medium-low caries, it is sufficient to use standard fluoride toothpastes (at least 1000 ppm) twice a day, while in carioreceptive subjects toothpastes with a high fluoride content can be used (with about 1, 500 ppm ), fluoride mouthwashes or fluorine paints periodically applied by the dentist. To maximize the beneficial effect of the fluoride contained in the toothpaste, it is advisable not to rinse or minimize rinsing after brushing.
The possible use of fluorinated supplements must be evaluated together with the dentist after a careful analysis of the amount of fluoride taken daily from other sources.
The administration of fluorinated supplements (tablets, drops) during pregnancy, in order to reduce the risk of caries of the unborn child, is not recommended given the lack of clear scientific evidence.
