Sites of implantation with compromised biology may be unable to achieve the required level of angiogenic and osteogenic regeneration. The specific function and contribution of different cell types to the formation of prevascularized, osteogenic networks in co-culture remains unclear. To determine how bone marrow-derived mesenchymal stromal cells (BMSCs) and endothelial cells (ECs) contribute to cellular proangiogenic differentiation, we analysed the differentiation of BMSCs and ECs in standardized monolayer, Transwell and co-cultures. BMSCs were derived from the iliac bone marrow of five patients, characterized and differentiated in standardized monolayers, permeable Transwells and co-cultures with human umbilical vein ECs (HUVECs). The expression levels of CD31, von Willebrand factor, osteonectin (ON) and Runx2 were assessed by quantitative reverse transcriptase polymerase chain reaction. The protein expression of alkaline phosphatase, ON and CD31 was demonstrated via histochemical and immunofluorescence analysis. The results showed that BMSCs and HUVECs were able to retain their lineage-specific osteogenic and angiogenic differentiation in direct and indirect co-cultures. In addition, BMSCs demonstrated a supportive expression of angiogenic function in co-culture, while HUVEC was able to improve the expression of osteogenic marker molecules in BMSCs.

Background: Nowadays, 3D planning and static for dynamic aids play an increasing role in oral rehabilitation of the masticatory apparatus with dental implants. The aim of this study is to compare the accuracy of implant placement using a 3D-printed drilling guide and an intraoral real-time dynamic navigation system. Methods: A total of 60 implants were placed on 12 partially edentulous lower jaw models. 30 were placed with pilot drilling guides, the other half with dynamic navigation (DENACAM^®). In addition, implant placement in interdental gaps and free-end situations were investigated. Accuracy was assessed by cone-beam computed tomography (CBCT). Results: Both systems achieved clinically acceptable results, yet more accurate results regarding the offset of implant base and tip in several spatial dimensions were achieved using drilling guides (each p < 0.05). With regard to angulation, real-time navigation was more precise (p = 0.0016). Its inaccuracy was 3°; the template-guided systems was 4.6°. Median horizontal deviation was 0.52 mm at base and 0.75 mm at tip using DENACAM^®. When using the pilot drill guide, horizontal deviation was 0.34 mm in the median and at the tip by 0.59 mm. Regarding angulation, it was found that the closer the drill hole was to the system's marker, the better navigation performed. The template did not show this trend (p = 0.0043; and p = 0.0022). Conclusion: Considering the limitations of an in vitro study, dynamic navigation can be used be a tool for reliable and accurate implantation. However, further clinical studies need to follow in order to provide an evidence-based recommendation for use in vivo.

Introduction. Bone tissue regeneration requires a three-dimensional biological setting. An ideal scaffold should enable cell proliferation and differentiation by mimicking structure and mechanical properties of the compromised defect as well as carrying growth factors. Two-photon polymerization (2PP) allows the preparation of 3D structures with a micrometric resolution. Methods. In this study, 2PP was applied to design scaffolds made from biocompatible methacrylated D,L-lactide-co- ε -caprolactone copolymers (LC) with a controlled porous architecture. Proliferation and differentiation of bone marrow mesenchymal stromal cells on LC was analyzed and compared to a standard inorganic urethane-dimethacrylate (UDMA) matrix. To functionalize LC and UDMA surfaces we analyzed a biomimetic, layer-by-layer coating, which could be modified in stiffness and integration of bone morphogenetic protein 2 (BMP2) and evaluated its effect on osteogenic differentiation. Results. On LC surfaces, BMSC demonstrated an optimal proliferation within pore sizes of 60–100 μ m and showed a continuous expression of Vimentin. On the polyelectrolyte multilayer coating a significant increase in BMSC proliferation and differentiation as marked by Osteonectin expression was achieved using stiffness modification and BMP2 functionalization. Conclusion. Combining 3D-Design with biofunctionalization, LC offers a promising approach for future regenerative applications in osteogenic differentiation of BMSCs.