SCCS deems hydroxyapatite (nano) safe for use in oral health care products
24 Mar 2023 --- The European Commission’s (EC) scientific advisory board, Scientific Committee on Consumer Safety (SCCS), has released its final opinion on the use of hydroxyapatite (nano) in oral cosmetic products.
The ingredient has been suggested to be safe when used at concentrations of up to 10% in toothpaste and up to 0.465% in mouthwash. The SCCS notes that hydroxyapatite (nano) can be used in skincare products at concentrations of up to 5%.
According to Oral Science, hydroxyapatite (nano) is a naturally occurring calcium phosphate compound indicated by Health Canada to reduce cavities. It is considered the “gold standard” oral health ingredient in Japan.
“Hydroxyapatite is a naturally occurring, water-insoluble mineral of a molecular weight of 502.31 g/mol. It is of hexagonal crystal structure comprising different crystal phases. Hydroxyapatite (nano) materials added to oral cosmetic products are listed either as powder or suspension,” the SCCS shares about the ingredient.
Hydroxyapatite as an ingredient is listed in the CosIng database – the EC database for information on cosmetic substances – without any reference to the nano form being used as an abrasive, for bulking and for stabilizing emulsions.
The SCCS safety evaluation only applies to hydroxyapatite (nano) with the following characteristics: composed of rod-shaped particles of which at least 95.8% (in particle number) have an aspect ratio less than three. The remaining 4.2% cannot have an aspect ratio exceeding 4.9 and the particles are not coated or surface modified.
The SCCS clarifies that the opinion does not apply to hydroxyapatite (nano) composed of needle-shaped particles. Moreover, it is not applicable to sprayable products such as breath spray that might expose the consumer’s lungs to nanoparticles by inhalation.
Safety first
Hydroxyapatite (nano) is increasingly replacing fluoride in toothpaste and mouthwash for protection against bacteria and decay which can lead to cavities, infections and other gum diseases.
“The nano-hydroxyapatite has a strong ability to bond with proteins, as well as with fragments of plaque and bacteria when contained in toothpaste,” research published in Annali di Stomatologia states.
The authors detail that in the 1970s, NASA pioneered synthetic hydroxyapatite as a repairing material as astronauts lost minerals from their teeth and bones due to the absence of gravity in space.
Japanese company Sangi Co. was the first to purchase the rights from NASA. In 1978, it launched a toothpaste that could repair the tooth enamel containing (nano) hydroxyapatite for the first time. Furthermore, in 2006, the first toothpaste containing synthetic hydroxyapatite biomimetic as an alternative to fluoride for remineralization and repairing tooth enamel appeared in Europe.
As hydroxyapatite is naturally occurring in human bodies, it is non-toxic and biocompatible. This also makes it safe for kids who may accidentally swallow toothpaste.
Nanoparticle mandate
The SCCS provides background information on the safety evaluation of hydroxyapatite (nano) to detail that given potential concerns to human safety, the Commission mandated the SCCS on the safety of hydroxyapatite (nano).
“Article 2(1)(k) of Regulation (EC) No. 1223/2009 (Cosmetics Regulation) states that ‘nanomaterial’ means an insoluble or biopersistent and intentionally manufactured material with one or more external dimensions, or an internal structure, on the scale from 1 to 100 nm,” shares SCCS.
It further elaborates that the nanomaterials definition covers materials in the nano-scale that are intentionally made, insoluble, partially soluble or biopersistent. It does not cover soluble, degradable, or materials non-persistent in biological systems.
“Article 16 of the EU Cosmetics Regulation requires cosmetic products containing nanomaterials other than colorants, preservatives and UV-filters and not otherwise restricted by the Cosmetics Regulation to be notified to the Commission six months before being placed on the market,” the SCCS elaborates.
Additionally, Article 19 of the regulation requires nano-scale ingredients to be labeled with the name of the ingredient, followed by “nano” in brackets.
By Radhika Sikaria
