Bioactivity Evaluation of Biphasic Hydroxyapatite Bone Substitutes Immersed and Grown with Supersaturated Calcium Phosphate Solution

Abstract

Recently, the frequency of use of bone substitute materials for the purpose of bone augmentation has increased in implant treatment, but bone formation with bone substitute materials alone is limited. Calcification of bone in the body progresses as Ca2+, H2PO4-, and HPO42- in the body form hydroxyapatite (HA) crystals. In this study, therefore, we prepared a biphasic bone substitute with biological activity to promote bone formation by inducing precipitation and growth of HA crystals on the surface of a bone substitute and evaluated it. Biphasic bone substitute granules were prepared by immersing HA granules in a supersaturated calcium phosphate solution prepared by mixing five medical infusion solutions, the precipitate was analyzed, and the biological activities of biphasic HA granules were evaluated in vitro and in vivo. As a result, the precipitated calcium phosphate crystals were identified as low crystalline HA. On the surface of the HA granules, low-crystalline HA grew markedly as needle-shaped crystals and significantly promoted cell proliferation and bone differentiation. In animal experiments, biphasic HA granules had a significantly higher bone mineral density, new bone volume ratio, and new bone area ratio. Therefore, it suggests that biphasic hydroxyapatite is a useful bone substitute for bone augmentation in dental implant treatment.

Effects of Scaffold Shape on Bone Regeneration: Tiny Shape Differences Affect the Entire System

“…Nevertheless, the chemical composition of scaffolds is only one factor affecting bone regeneration. The porosity of scaffolds is also a dominant influencing factor. − Introducing channels (>100 μm in apertural size) into scaffolds is an effective approach to facilitate the penetration of tissues and cells into the scaffold, thereby promoting bone regeneration. − Granular scaffolds with macropores (>100 μm in diameter) rather than channels can be fabricated using various methods. − However, the macropores introduced into granular scaffolds by conventional approaches, such as sacrificial template and gas forming methods, − show poor interconnectivity and irregular size and shape. In addition, not all granular scaffolds develop macropores.…”

Granular honeycomb scaffolds composed of carbonate apatite for simultaneous intra- and inter-granular osteogenesis and angiogenesis

“…Granular, rather than blockish, scaffolds (<2 ​mm) are used in clinical dentistry because their defect sizes in bone are usually small [ [27] , [28] , [29] , [30] , [31] , [32] , [33] , [34] ]. Macroporous granules are more favorable than dense granules (DGs) for the rapid ingrowth of bone [ [35] , [36] , [37] , [38] , [39] , [40] , [41] , [42] , [43] , [44] , [45] ].…”

Special Issue: Advances in Dental Bio-Nanomaterials

“…Thereafter, Yamaguchi [ 8 ] prepared and evaluated a biologically active biphasic bone substitute to promote bone formation by inducing precipitation and growth of HA crystals on the surface of a bone substitute. Biphasic bone substitute granules were prepared by immersing HA granules in a supersaturated calcium phosphate solution prepared by mixing five medical infusion solutions, and subsequently the precipitate was analyzed and the biological activities of the biphasic HA granules were evaluated in vitro and in vivo.…”