Safety and efficacy of PLGA(Ag-Fe(3)O(4))-coated dental implants in inhibiting bacteria adherence and osteogenic inducement under a magnetic field

INTRODUCTION: The placement of dental implants is performed in a contaminated surgical field in the oral cavity, which may lead to implant failure. Bacterial adhesion and proliferation (Streptococcus mutans, Porphyromonas gingivalis) often lead to implant infections. Although Ag nanoparticles hold great promise for a broad spectrum of antibacterial activities, their runoff from dental implants compromises their antibacterial efficacy and potentially impairs osteoblast proliferation. Thus, this aspect remains a primary challenge and should be controlled. MATERIALS AND METHODS: In this study, PLGA(Ag-Fe(3)O(4)) was modified on the implanted tooth surface and was characterized by transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The magnetic and antibacterial properties were also determined. RESULTS: Results showed that Ag successfully bonded with Fe(3)O(4), and Ag-Fe(3)O(4) not only exerted superparamagnetism but also exhibited antibacterial activity almost identical to silver nanoparticles (nano-Ag). The PLGA(Ag-Fe(3)O(4)) coating could significantly maintain the antibacterial activity and avoid bacterial adhesion to the implant. Compared with the blank control group, PLGA(Ag-Fe(3)O(4)) under magnetic field-coated samples had a significantly lower amount of colonized S. mutans (P<0.01). Osteoblast proliferation results showed that the coated samples did not exhibit cytotoxicity and could promote osteoblast proliferation as shown by MTT, alkaline phosphatase, and the nucleolar organizer region count. CONCLUSION: We developed a novel Ag biologically compatible nanoparticle in this study without compromising the nano-Ag antibacterial activity, which provided continuous antibacterial action.