The SCCS has issued an opinion concluding that hydroxyapatite in nanoform is safe for use in toothpaste up to a maximum concentration of 29.5% and in mouthwash up to a maximum concentration of 10%, under reasonably foreseeable exposure conditions. This safety assessment applies only to rod-shaped particles where at least 87% have aspect ratios equal to or less than 3, and the remaining 13% have aspect ratios not exceeding 9. The opinion explicitly does not apply to coated, surface-modified, or needle-like particles.
The conclusion is based on toxicological studies showing that hydroxyapatite (nano) does not present mutagenic hazards, cytotoxicity, or inflammatory effects, even when tested at high concentrations in buccal mucosa models. The SCCS noted that uptake through the oral mucosa was considered negligible. Furthermore, epithelial cells in the mucosa are constantly replaced, and any unintentionally ingested particles undergo rapid dissolution in gastric fluid, further reducing potential risks.
The Opinion is open for comments until 30th May 2025.
