Permalink : http://hdl.handle.net/2115/67331

KEYWORDS : nanotubes;NAC;dental implant;drug delivery;osseointegration

New strategies involving drugs loading onto implant surfaces are required to enhance osseointegration and shorten healing time after implantation. In this study, we examined the feasibility of N -acetyl cysteine (NAC)-loaded nanotube titanium (NLN-Ti) implants as a potential drug delivery system. To determine the effect of NLN-Ti in in vitro and in vivo, viability and ROS formation was assessed and enzyme-linked immunosorbant assay (ELISA), Western blot, micro-computed tomography (μ-CT), hematoxylin and eoxin (H&E) staining and immunohistochemical (IHC) analysis were performed. In vitro, cell viability was increased and inflammatory responses and reduced oxidative stress-related defense were decreased with MC 3T3-E1 cells exposed to a sustained release of NAC from NLN-Ti implants. Following NLN-Ti implant installation, μ-CT and histomorphometric analysis revealed an increase of newly formed bone volume and bone mineral density in the mandibles of Sprague Dawley rats and beagle dogs. Relatively well-formed new bone was demonstrated in close contact to the NLN-Ti implant surface by H&E staining. IHC revealed a significantly higher expression of bone morphogenetic protein-2, -7 and heme oxygenase-1, and reduced the expression of the receptor activator of nuclear factor-kappa B ligand. The data indicate that NLN-Ti implants enhance osseointegration and highlight the value of the animal model in assessing diverse biological responses to dental implants.