 The study investigates the possibility of increasing calcium ion release from hydroxyapatite HAP, nanoparticles by reducing their size, with the highest release observed in HAP with a specific surface area of 240 square meters per G and an average nanoparticle size of 9 nanometers. This article was authored by Ursula Solage, Agnias Kachodara, Stanislaw Terlaka, and others. The study investigates the possibility of increasing calcium ion release from hydroxyapatite HAP with a specific surface area of 240 square meters per G and a average nanoparticle size of 9 nanometers per G.