A novel experimental approach to evaluate guided bone regeneration (GBR) in the rat femur using a 3D-printed CAD/CAM zirconia space-maintaining barrier.

INTRODUCTION: Obtaining a certain bone volume is an important goal in implantology or orthopedics. Thus, after tooth extraction, quite a lot of horizontal and vertical alveolar bone is lost in time and can be detrimental to the implant treatment outcome, while the treatment of critical bone defects is a considerable challenge for surgery. OBJECTIVES: In this study we designed a new in vivo model as an useful experimental tool to assess guided bone regeneration (GBR) using a computer-aided design/manufacturing (CAD-CAM) space-maintaining barrier. METHODS: The barrier was 3D printed with three progressive heights, surgically placed on rat femur, and GBR results were analyzed at 2, 4, and 8 weeks by X-ray and bone mineral density analysis, histology/morphometry and by immunofluorescence and immunohistochemistry for osteogenesis and angiogenesis evaluation. RESULTS: The obtained results show that the proposed experimental model provides a real-time useful information on progressive bone tissue formation, which depends on the volume of isolated space created for GBR and on molecular events that lead to satisfactory vertical and horizontal bone augmentation and osteointegration. CONCLUSION: In conclusion, the proposed customized three-dome space-maintaining barrier is suitable as an experimental tool to assess the potential of using the designed barriers in dentistry and orthopedics to promote the formation of new bone and determine their space- and time-dependent limitations. Meanwhile, guided bone augmentation for dentistry requires subsequent evaluation on an alveolar bone preclinical model followed by clinical implementation.

Nanostructured Thin Coatings Containing Anthriscus sylvestris Extract with Dual Bioactivity.

Plant extracts are highly valuable pharmaceutical complexes recognized for their biological properties, including antibacterial, antifungal, antiviral, antioxidant, anticancer, and anti-inflammatory properties. However, their use is limited by their low water solubility and physicochemical stability. In order to overcome these limitations, we aimed to develop nanostructured carriers as delivery systems for plant extracts; in particular, we selected the extract of Anthriscus sylvestris (AN) on the basis of its antimicrobial effect and antitumor activity. In this study, AN-extract-functionalized magnetite (Fe3O4@AN) nanoparticles (NPs) were prepared by the co-precipitation method. The purpose of this study was to synthesize and investigate the physicochemical and biological features of composite coatings based on Fe3O4@AN NPs obtained by matrix-assisted pulsed laser evaporation technique. In this respect, laser fluence and drop-casting studies on coatings were performed. The physical and chemical properties of laser-synthesized coatings were investigated by scanning electron microscopy, while Fourier transform infrared spectroscopy comparative analysis was used for determining the chemical structure and functional integrity. Relevant data regarding the presence of magnetic nanoparticles as the only crystalline phase and the size of nanoparticles were obtained by transmission electron microscopy. The in vitro toxicity assessment of the Fe3O4@AN showed significant cytotoxic activity against human adenocarcinoma HT-29 cells after prolonged exposure. Antimicrobial results demonstrated that Fe3O4@AN coatings inhibit microbial colonization and biofilm formation in clinically relevant bacteria species and yeasts. Such coatings are useful, natural, and multifunctional solutions for the development of tailored medical devices and surfaces.

Functionalized Antimicrobial Composite Thin Films Printing for Stainless Steel Implant Coatings.

In this work we try to address the large interest existing nowadays in the better understanding of the interaction between microbial biofilms and metallic implants. Our aimed was to identify a new preventive strategy to control drug release, biofilm formation and contamination of medical devices with microbes. The transfer and printing of novel bioactive glass-polymer-antibiotic composites by Matrix-Assisted Pulsed Laser Evaporation into uniform thin films onto 316 L stainless steel substrates of the type used in implants are reported. The targets were prepared by freezing in liquid nitrogen mixtures containing polymer and antibiotic reinforced with bioglass powder. The cryogenic targets were submitted to multipulse evaporation by irradiation with an UV KrF* (λ = 248 nm, τFWHM ≤ 25 ns) excimer laser source. The prepared structures were analyzed by infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and profilometry, before and after immersion in physiological fluids. The bioactivity and the release of the antibiotic have been evaluated. We showed that the incorporated antibiotic underwent a gradually dissolution in physiological fluids thus supporting a high local treatment efficiency. Electrochemical measurements including linear sweep voltammetry and impedance spectroscopy studies were carried out to investigate the corrosion resistance of the coatings in physiological environments. The in vitro biocompatibility assay using the MG63 mammalian cell line revealed that the obtained nanostructured composite films are non-cytotoxic. The antimicrobial effect of the coatings was tested against Staphylococcus aureus and Escherichia coli strains, usually present in implant-associated infections. An anti-biofilm activity was evidenced, stronger against E. coli than the S. aureus strain. The results proved that the applied method allows for the fabrication of implantable biomaterials which shield metal ion release and possess increased biocompatibility and resistance to microbial colonization and biofilm growth.