Hydroxyapatite is a mineral from the calcium phosphate family and is characterized by an extremely high degree of hardness. It is a substance found in our bones and teeth. Whilst bones are formed from around 40% hydroxyapatite, the concentration in our teeth is far higher. In the tooth structure, around 70% of the inner dentine consists of this mineral. The outer enamel actually consists of as much as 97% hydroxyapatite, which makes it the hardest substance in the human body.

Although the mineral hydroxyapatite is highly resistant, it is not impervious to wear: Over a lifetime, enamel wears away as a result of daily chewing. In an acid environment with a pH below 5.5, hydroxyapatite is also slowly dissolved from the enamel. The bacteria which are naturally present in our oral microbiome break down sugar, producing acids.

In addition, acidic foods can intensify this effect. The fruit acids in fruit juices or additives in sparkling drinks, or phosphoric acid, also damage the crystalline compounds in enamel.

The enamel protects the underlying layers of the tooth from the penetration of bacteria, which can cause oral diseases such as cavities and may even lead to the death of the tooth. It also seals off the small nerve channels (dentinal tubules), protecting them from external influences. Hydroxyapatite is therefore essential for strong and healthy teeth.

Sensitive teeth that react with pain to cold, heat or the consumption of sweet or sour foods can be an indication of exposed dentine and the loss of hydroxyapatite. Since the body cannot reproduce hydroxyapatite itself external support is required.

The outstanding results on the mode of action of hydroxyapatite have already been demonstrated in more than 200 international studies including clinical trials. During brushing, the microcrystalline structure of hydroxyapatite is proven to adhere to the enamel surface. It remineralises microscopic defects whereby it form a protective layer that prevents the natural enamel from daily wear and tear.

With the daily use of Bioniq® or KinderKarex Toothpastes, teeth not only feel smoother, but also stay cleaner for longer, as the bacteria find it harder to build up on the surface of the teeth. The formation of dental plague is reduced preventing cavities and protecting healthy gums. Sensitivity to pain is also reduced. At the same time hydroxyapatite also has a visual effect, due to the white nature of the biomimetic crystallites tooth-discoloration caused by so-called extrinsic stain, for example from nicotine, tea or red wine can be reduced.