Hydroxyapatite and artificial enamel

Hydroxyapatite in dental care

Our teeth mainly consist of the mineral hydroxyapatite, which is one of the hardest substances in the human body. This substance makes the dental enamel hard and resistant, protecting the teeth from acids and bacteria. Hydroxyapatite is therefore essential for strong, healthy teeth. However, this mineral wears away over time and cannot be restored by the human body. To maintain healthy teeth, biomimetic hydroxyapatite – better known as artificial enamel – adheres the teeth with the daily use of Bioniq® Repair products.

In this article you can discover why hydroxyapatite is important for oral health and how bionics and biomimetics can also be harnessed to "rebuild" even badly damaged teeth.

What is hydroxyapatite?

Hydroxyapatite is a mineral from the calcium phosphate family and is characterised 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.

All in all, this is quite a powerful substance. However, the hydroxyapatite in enamel in particular wears away naturally over time and cannot be reproduced by the human body.

What damages hydroxyapatite?

Hydroxyapatite is not impervious

Although the mineral apatite 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.

Mechanical irritants can lead to signs of wear: the enamel on the masticatory surfaces (of opposing teeth) in particular is worn away little by little as a result of tooth grinding. Aggressive brushing or the use of toothbrushes with hard bristles can also damage the enamel and virtually brush it away.

Why is hydroxyapatite important?

The outermost layer of the teeth, the enamel, has an extremely high concentration of 97% hydroxyapatite. Enamel protects the underlying layers from the penetration of bacteria, which can cause oral diseases such as cavities and can lead to the death of the tooth.

It also seals off the small nerve channels (dentinal tubules), protecting them from external influences. 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.

Furthermore, this substance also has a cosmetic effect. Hydroxyapatite is white. Thanks to the high concentration in dental enamel, our teeth appear whiter. Of course the underlying dentine also comprises around 70% hydroxyapatite, but it appears much more yellow in comparison. Hence, intact enamel and hydroxyapatite are the key to naturally white teeth.

Is it possible to halt the natural wearing away of the enamel? Sadly, the body is unable to make this substance itself. However, science has found a way to recreate hydroxyapatite in the laboratory and to incorporate it in oral care products. Say goodbye to enamel wear with just one layer!

Hydroxyapatite from bionics

Hydroxyapatite from bionics

Fortunately, nowadays it is possible to reproduce enamel thanks to innovation and progress in dental technology. So-called artificial enamel is bionic or biomimetic hydroxyapatite and is based on the principle of bionics. The term "bionics" combines "biology" and "techniques". It refers to the application of a natural phenomenon to a technical system. This concept has already been used successfully in everyday objects:

  • The camera lens was modelled on the human eye 
  • Mop heads are inspired by octopus tentacles 
  • Hook-and-pile fasteners are based on the way the hooks on burrs attach themselves to things 
  • The water- and dirt-repellent lotus effect 
  • Helicopters are inspired by dragonflies 
  • Thanks to fine lateral grooves, the skin of the common sandfish is incredibly smooth – making it the ideal model for the surface of solar energy plants 
  • The tiny holes in the seed pods of the poppy plant were the inspiration for salt shakers 
  • The woodpecker's special ability influenced the invention of the pneumatic hammer 
  • The shape of the trout provided the template for airships 
  • Shark skin was copied when making diving suits, to minimise the friction between the water and the body's surface 

These are just a few examples from the field of bionics. Nature is a popular model as we know that it works. These systems have often been tried and tested for thousands of years and have come out on top in the process of evolution. Now we're learning from them!

Biomimetic hydroxyapatite in Bioniq® Repair products

All Bioniq Repair products contain artificial enamel

Most accomplishments in the field of bionics bring forth technical innovations. With the production of biomimetic hydroxyapatite, it has not only been possible to remodel a mineral substance, but also to combine it with a toothpaste. This is why Bioniq® Repair products also echo the blend “biology” and “technique” in their name.

All Bioniq® Repair-Toothpastes and the Tooth-Milk contain the innovative active substance biomimetic hydroxyapatite, also known as artificial enamel. With this ingredient, we can give teeth what they need to remain healthy for longer.

During brushing, the microcrystalline structure of hydroxyapatite builds up directly on the enamel surface, enabling it to repair small cracks and porous areas in the enamel. With the daily use of Bioniq® Repair-Toothpaste, teeth not only feel smoother, but also stay cleaner for longer, as the bacteria which are present in all healthy oral microbiomes are unable to adhere as effectively to the surface of the teeth. Sensitivity to pain is also reduced.

Numerous studies also demonstrate that biomimetic hydroxyapatite has a positive effect on oral health. See for yourself!

Bioniq® Repair products with artificial enamel