Recently, hydroxyapatite has gained significant attention as a natural alternative to fluoride for strengthening and remineralising teeth. Hydroxyapatite is a calcium phosphate compound that makes up around 97% of tooth enamel and 70% of dentin, meaning it’s an inherently biocompatible material. However, not all hydroxyapatite is created equal. The difference lies primarily in the particle size, and that’s where important safety and efficacy considerations emerge.
Nano-Hydroxyapatite
Nano-hydroxyapatite (nHAp) consists of extremely small particles, typically less than 100 nanometres in size. Its tiny dimensions allow it to penetrate microscopic defects in enamel, theoretically offering efficient remineralisation. This has led to its inclusion in various toothpastes and oral care products, particularly in Japan and parts of Europe.
However, growing safety concerns have been raised about nanoparticles in general. Because of their small size, nanoparticles can potentially enter the body through mucosal membranes or be absorbed into cells. Once inside, nanoparticles could interact with biological tissues in unpredictable ways, potentially leading to inflammation or oxidative stress. Although the data on nano-hydroxyapatite specifically remains limited, regulatory bodies like the European Chemicals Agency (ECHA) have expressed caution, noting that the long-term biological impact of nanomaterials is not yet fully understood.
Furthermore, some studies have questioned whether nano-sized particles are truly necessary for effective remineralisation. Enamel lesions and surface damage are generally on the micrometre scale, meaning that microparticles (larger than nanoparticles) still effectively bind to and restore the enamel surface without the same safety concerns.
Micro-Hydroxyapatite
Micro-hydroxyapatite (μHAp) features slightly larger particles, typically between 1 and 10 micrometres, that are still small enough to adhere to tooth enamel but large enough to prevent cellular absorption. Research has shown that micro-hydroxyapatite forms a protective mineral layer over the tooth surface, filling in small irregularities and reducing sensitivity. It supports enamel remineralisation through ion exchange, releasing calcium and phosphate to rebuild the mineral matrix naturally.
Crucially, micro-hydroxyapatite’s biocompatibility has been well established. Its particle size keeps it from penetrating gum tissue or being ingested at the cellular level, making it a safer and more stable alternative for everyday use. Studies have demonstrated that it can reduce plaque formation, whiten teeth naturally, and alleviate sensitivity – all without the potential risks associated with nanomaterials.
Dimples’ Commitment to Safe, Effective Oral Care
At Dimples, we believe that healthy smiles shouldn’t come at the expense of safety. That’s why our toothpaste harnesses the proven remineralising power of micro-hydroxyapatite, not nano. Our formula strengthens and smooths enamel, gently reduces sensitivity, and helps restore your teeth’s natural brightness, all while being kind to your body and the environment. With Dimples, you can enjoy a clean, confident smile knowing your toothpaste is both effective and safe.