Fabrication and histological evaluation of a self-setting granular cement using calcium sulfate hemihydrate granules with different pore distribution.

Granular type of bone substitutes is currently used in the field of dentistry to restore alveolar bone defects. However, the migration of the granules from the implantation site is still an unresolved issue. In this study, the feasibility to fabricate self-setting calcium sulfate hemihydrate (CSH) granules using different ranges of loading pressure: CSH(0), CSH(50), CSH(100), and CSH(150) was investigated with the hypothesis that CSH granules with reduced microporosity can inhibit the rapid dissolution rate of the calcium sulfate dihydrate (CSD) set blocks and induce bone regeneration. After 4 weeks of implantation, the granules were mostly replaced with new bone although no significant differences were observed. Nevertheless, the granules demonstrated the ability to set within the bone defect. It is therefore concluded that the setting ability of calcium sulfate can contribute to address the issue of migration of the granules and provide a useful guide for designing setting bone substitutes.

Antibacterial and osteogenic thin films on Ti-6Al-4V surface formed by passivation process in copper hydroxide solution.

Implant-associated infections are threatening and devastating complications that lead to bone destruction and loss. As a smooth surface is suitable for inhibiting bacterial adhesion, endowing antibacterial activity to the Ti surface without any structural changes in the surface topography is an effective strategy for preventing infection. The thin film on the Ti-6Al-4 V surface was functionalized to endow antibacterial activity by immersion in a Cu(OH)2 solution. The resulting surface maintains the surface topography with a surface roughness of 0.03 µm even after the immersion in the Cu(OH)2 solution. Moreover, Cu was detected at approximately 10 atom% from the surface and was present up to a depth of 30 nm of thin film. In vitro experiments revealed that the resulting surface exhibited antibacterial activity against methicillin-resistant Staphylococcus aureus and allowed the cellular proliferation, differentiation, and calcification of MC3T3-E1 cells. Furthermore, in vivo experiments determined that the presence of Cu in the thin film on the Ti-6Al-4 V surface led to no inflammatory reactions, including bone resorption. Thus, immersion in a Cu(OH)2 solution incorporates and immobilizes Cu into the thin film on the Ti-6Al-4 V surface without any structural alternations in the surface topography, and the resulting smooth surface exhibits antibacterial activity and osteogenic cell compatibility without cytotoxicity or inflammatory reactions. Our findings provide fundamental insights into the surface design of Ti-based medical devices, to achieve bone reconstruction and infection prevention.

Passivation of Ti-6Al-4V in Cu(OH)2 solution endowed smooth thin film with antibacterial activity and osteogenic cell compatibility for potentially achieving both bone reconstruction and infection prevention.