Nano-Pore Size of Alumina Affects Osteoblastic Response.

The rapid development and application of nanotechnology to biological interfaces has impacted the bone implant field, allowing researchers to finely modulate the interface between biomaterials and recipient tissues. In the present study, oxidative anodization was exploited to generate two alumina surfaces with different pore diameters. The former displayed surface pores in the mean range of 16-30 nm, while in the latter pores varied from to 65 to 89 nm. The samples were characterized by Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray spectroscopy (EDX) analysis prior to being tested with pre-osteoblastic MC3T3-E1 cells. In vitro cell response was studied in terms of early cell adhesion, viability, and morphology, including focal adhesion quantification. Both the alumina samples promoted higher cell adhesion and viability than the control condition represented by the standard culture dish plastic. Osteogenic differentiation was assessed through alkaline phosphatase activity and extracellular calcium deposition, and it was found that of the two nano-surfaces, one was more efficient than the other. By comparing for the first time two nano-porous alumina surfaces with different pore diameters, our data supported the role of nano-topography in inducing cell response. Modulating a simple aspect of surface texture may become an attractive route for guiding bone healing and regeneration around implantable metals.

An alumina toughened zirconia composite for dental implant application: in vivo animal results.

Ceramic materials are widely used for biomedical applications because of their remarkable biological and mechanical properties. Composites made of alumina and zirconia are particularly interesting owing to their higher toughness with respect to the monolithic materials. On this basis, the present study is focused on the in vivo behavior of alumina toughened zirconia (ATZ) dental implants treated with a hydrothermal process. A minipig model was implemented to assess the bone healing through histology and mRNA expression at different time points (8, 14, 28, and 56 days). The novel ATZ implant was compared to a titanium clinical standard. The implants were analyzed in terms of microstructure and surface roughness before in vivo tests. The most interesting result deals with a statistically significant higher digital histology index for ATZ implants with respect to titanium standard at 56 days, which is an unprecedented finding, to the authors' knowledge. Even if further investigations are needed before proposing the clinical use in humans, the tested material proved to be a promising candidate among the possible ceramic dental implants.

Presence of osteoinductive factors in bovine colostrum.

New approaches in the treatment of skeletal defects may benefit from the use of soluble biological factors. We previously standardized a derivative of bovine colostrum (SBCD), deprived of casein and fat and rich in cytokines. In the present study, we tested its possible use as an adjuvant in bone healing. SBCD contained factors involved in stromal cell stimulation and differentiation and induced cytokine production from stimulated mesenchymal stem cells (MSCs). In vitro, SBCD promoted proliferation, migration and, in association with osteogenic factors, osteogenic differentiation of osteoblastic and MSCs. In in vivo experiments of subcutaneous Matrigel injection in mice, SBCD plus hydroxyapatite, but not hydroxyapatite nor SBCD alone, induced recruitment of macrophages and stromal cells. After 60 days, plugs containing SBCD and hydroxyapatite were densely calcified and diffusely positive for osteocalcin, supporting the occurrence of an early osteogenic process. These results indicate that SBCD is a rich source of factors with osteoinductive properties.