1. Hydroxyapatite , calcium carbonate and calcium phosphate is deposited around the cell.2. Common temporary fillers include hyaluronic acid and calcium hydroxyapatite preparations. 3. The calcium hydroxyapatite , the normal material of mammalian bone. 4. There is also microretention from porosities occurring in the hydroxyapatite . 5. These structures are made of crystalline calcium phosphate in the form of hydroxyapatite . 6. Calcium hydroxyapatite and calcite precipitates can be found around bacteria in alluvial topsoil. 7. Tooth enamel is composed of almost ninety percent hydroxyapatite . 8. Enamel, itself, is composed of hydroxyapatite , a calcium phosphate crystal. 9. Etidronate is a bisphosphonate and can reduce the formation of calcium hydroxyapatite crystals. 10. The same is true of hydroxyapatite , the material that bones are made of.