Fluorine: Function & Diseases

Fluorine represents a chemical element with atomic number 9 and belongs to the halogens. It is a strongly corrosive gas, which causes the most severe destruction of mucous membranes. Fluorine is used medicinally in the form of its salts, fluorides, to strengthen teeth.

What is fluorine?

Fluorine represents a highly corrosive and reactive gas. It is not a compound, but a chemical element belonging to the halogens. With atomic number 9, it is the lightest halogen. In nature, fluorine occurs mainly in the form of its salts, the fluorides. The gas fluorine is not very stable and reacts immediately after its production with almost all compounds and elements. Only with the noble gases helium and neon no reaction takes place. This extraordinarily strong reactivity can be explained by its very strong affinity for electrons. It always withdraws electrons from its reaction partners and is thus the strongest oxidizing agent. The name fluorine is derived from the Latin “fluores” (flow). As calcium fluoride (fluorspar), it serves as a flux for ores. When fluorspar is added to ores, it lowers their melting point so that they become liquid more quickly. In medicine, the term fluor genitalis is used for the bloodless discharge of secretions from the female genitalia. However, fluor genitalis should in no way be confused with the element fluorine.

Function, effects, and tasks

Fluorine is called an essential trace element. However, this importance of fluorine is controversial. It is known that fluorides have protective properties towards teeth. Fluorides can strengthen the teeth and at the same time inhibit certain enzymes of caries bacteria, which cause the decomposition of carbohydrates. In this process, fluorides act directly on the tooth. Oral intake of fluoride does not show any effect on the teeth. Teeth are mainly composed of the mineral hydroxyapatite. Hydroxyapatite is attackable by acids, which are formed by the decomposition of food residues. Therefore, poor dental hygiene often results in holes in the teeth, which continue to be occupied by caries bacteria. If, for example, the toothpaste contains fluoride, hydroxyl ions are exchanged for fluoride ions. This produces fluorapatite, which is harder and less vulnerable to acids. Thus, even hydroxyapatite dissolved by acids can be precipitated again as fluorapatite in the presence of fluorides. Incipient destruction can thus be reversed. But fluorides also have positive properties for the structure of bones. Here, the absorption takes place orally. For example, children and infants are given fluorides and vitamin D to prevent rickets. Fluorides must not be overdosed, however, so that fluorosis with stiffening and thickening of the joints cannot develop. Fluorine compounds are also approved as medications for osteoporosis. Here, the corresponding tablets contain sodium fluoride or disodium fluorophosphate.

Formation, occurrence, properties, and optimal values

Fluorine is present in the form of fluorides in black and green tea, asparagus or even fish. Many salts contain fluoride. Pure fluorine salts do not exist because of the low solubility of fluoride-containing compounds in water. Fluorspar (calcium fluoride) and fluorapatite occur most frequently in the earth’s crust. Fluorine is mainly produced from calcium fluoride. There are even organisms that can produce organofluorine compounds. For example, the South African gifblaar or plants of the genus Dichapetalum can synthesize fluoroacetic acid against predators. The human organism has a requirement of 0.25-0.35 mg daily.

Diseases and disorders

However, poisoning and health problems are more frequently known in connection with fluorine. As mentioned earlier, pure fluorine is a very toxic corrosive gas. This is also what makes fluorine so difficult to manufacture. Because it reacts with almost all materials, it is also very difficult to store and transport. When poisoned with fluorine, burns and burns occur in the lungs, on the skin and in the eye. Depending on the dose, dissolution of the corresponding organs occurs within a short time, resulting in death. The lethal dose is very low and amounts to 185 ppm. Fluorine poisoning with pure fluorine will rarely occur because the gas is not stable. However, poisoning with hydrogen fluoride is similarly dangerous.Hydrogen fluoride forms hydrogen bonds with the proteins in the body, destroying the tertiary structure of the proteins. Denaturation of body proteins takes place. Fluorides can form complex compounds with aluminum ions that act similarly to phosphates. In the body, these compounds interfere with phosphorylation reactions. Among other things, this results in the deregulation of G-proteins, with many enzymes being inhibited. For this reason alone, an increased dose of fluorides is not tolerated by the body. If too much fluoride-containing tablets are taken, nausea, vomiting and diarrhea may also occur. In the process, the fluorides react with the stomach acid, forming hydrofluoric acid to a small extent. This attacks the mucous membranes. Chronic mild overdose of fluorides may result in fluorosis. Fluorosis is chronic fluorine poisoning with changes in the structure of tooth enamel, coughing, expectoration and shortness of breath. In the teeth, too much hydroxyapatite transforms into fluoroapatite. In the process, the teeth become more brittle. The bones also change due to the excessive formation of fluorapatite. Slow stiffening and remodeling of the bones occurs. In addition, the enzyme enolase is inhibited.