Hydroxyapatite (HA or HAp) is the main component of enamel, which gives an appearance of bright white and eliminates the diffuse reflectivity of light by closing the small pores of the enamel surface. Hydroxyapatite has long been among the most studied biomaterials in the medical field for both its proven biocompatibility and for being the main constituent of the mineral part of bone and teeth. HA represents 90% of the weight of the tooth enamel.
Since its approval as an anti-caries agent in 1993 in Japan, it has become available commercially in Europe in 2006 and in Canada in 2015. It is widely considered an effective, non-toxic alternative to fluoride which is known to cause developmental neurotoxicity as well as toxicity among adults at high levels of consumption.
Resources:
1.Healthline: What is Hydroxyapatite Toothpaste
2.Hydroxyapatite and its applications in preventive, restorative and regenerative dentistry: a review of literature
3.Ask the Dentist: Hydroxyapatite. What It is, Benefits...