Comparison of the Bone Forming Ability of Different Sized-alpha Tricalcium Phosphate Granules using a Critical Size Defect Model of the Mouse Calvaria

63 Introduction Bone defects attributed to serious periodontitis, trauma, and injury are commonly encountered in the fields of dentistry, craniofacial surgery, and orthopedics. Although autogenous bone grafting is still considered the gold standard for treatment, this process has several drawbacks, such as the requirement of a second surgery and the limited availability of collectable bone [1]. Artificial bone grafts are thought to be promising alternatives to autogenous bone grafts. Several calcium phosphate (CaP)-based biomaterials, such as hydroxyapatite (HA), tricalcium phosphate (TCP), and octacalcium phosphate (OCP), have been intensively investigated for use as artificial bone because, under appropriate conditions, these materials show excellent biocompatibility and bioactivity [2, 3]. High-temperature TCP, known as alpha-tricalcium phosphate (-TCP), is often prepared by the sintering of amorphous precursors with the proper composition [4]. Its calciumto-phosphate ratio is theoretically 1.50. In general, -TCP dissolves more easily than OCP, -TCP, and HA under neutral pH conditions [4]. Furthermore, -TCP converts to apatite in aqueous solution over time [5], to lowComparison of the Bone Forming Ability of Different Sized-alpha Tricalcium Phosphate Granules using a Critical Size Defect Model of the Mouse Calvaria