Preparation, Characterization and Evaluation of Biodegradable and Antibacterial Ploy (lactide-co-glycolide)-Hydroxyapatite-Bioactive glass Nanocomposite Coating for Dental and Orthopedic Implants The aim of this research was the preparation, characterization, and evaluation of biodegradable and antibacterial poly (lactide-co-glycolide)/hydroxyapatite/bioactive glass (PLGA/HA/BG) nanocomposite coating for dental and orthopedic implants. Three types of bioactive glass nanoparticles with different compositions (58S, 63S, and 72S) were synthesized via sol-gel technique. Antibacterial activity against four aerobic bacteria and cytotoxicity of the bioactive glass nanoparticles were evaluated. Subcutaneous connective tissue reactions of rats to the bioactive glass nanoparticles and their bioactivity were evaluated. Three types of nanocomposite coatings (PLGA/HA/BG, PLGA/HA, and PLGA/BG) were prepared. In PLGA/HA/BG nanocomposite coating, equal amounts of HA and BG nanoparticles was used. Scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDS), XRD, and Atomic force microscopy (AFM) were used to characterize the coatings. Adipose-derived stem cells adhesion, viability, and proliferation on the coatings were evaluated via MTT assay. Degradation and bioactivity of the nanocomposite coatings were evaluated. Nanocomposite coatings adhesion to Kirschner wires (K-wires) was evaluated in vivo. Based on the results, 58S and 63S bioactive glass nanoparticles showed more bioactivity than 72S bioactive glass nanoparticles. 58S composition showed the most antibacterial activity. Bioactive glass nanoparticles showed no cytotoxicity and 58S and 72S compositions induced more cell proliferation. In vivo test indicated that the tissue suffers the nanoparticles. PLGA could not entrap the nanoparticles in concentrations more than 10 wt% (15 and 20 wt %). Coatings showed no cytotoxicity and PLGA/HA/BG and PLGA/BG nanocomposite coatings induced adhesion and proliferation of the cells. In vitro degradation study showed the entire degradation of the coatings at about two months. Apatite formation on the nanocomposite coatings with good cell response was well observed. Evaluation of nanocomposite coatings adhesion on k-wires showed that they remained stable on the implants at about 96% of the original coatings mass. Bioegradable and antibacterial PLGA/HA/BG nanocomposite coating capable to induce stem cells adhesion and proliferation with suitable adhesion to the implant could be used as a good candidate on dental and orthopeadic implants to increase the rate of bone tissue repair in an antibacterial environment. Keywords: Nanocomposite coating, Antibacterial, Biodegradable, Poly (lactide-co-glycolide), Bioactive glass, Hydroxyapatite, Stem cell.