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There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
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Co-Advisors: Dr. Barbara D. Boyan (Department of Biomedical Engineering), Dr. Rina
Tannenbaum (School of Materials Science & Engineering)
Committee Members:
Dr. Zvi Schwartz (Department of Biomedical Engineering)
Dr. Kenneth H. Sandhage (School of Materials Science & Engineering)
Dr. Robert J. Butera (School of Electrical Engineering)
Dental and orthopaedic implants are currently the solution of choice for teeth and joint replacements with success rates continually improving, but they still have undesirable failure rates in patients who are compromised by disease or age, and who in many cases are the ones most in need. The success of titanium (Ti) implants depends on its ability to osseointegrate with the surrounding bone and this, in turn, is greatly dependent on the surface properties of the device. Surface modifications of Ti implants at the microscale have driven improved biological performance by mimicking the hierarchical structure of bone associated with regular bone remodeling. Recently, the clinical application of surface nanomodification of implants has been evaluated. Still, most clinically available devices remain smooth at the nanoscale and fundamental questions remain to be elucidated about the effect of nanoroughness on the initial response of osteoblast lineage cells. Additionally, the presence of endogenous electrical signals in bone has been implicated in the processes of bone remodeling and repair. The existence of these native signals has prompted the use of external electrical stimulation to enhance bone growth in cases of fractures with delayed union or nonunion, with several in vitro and in vivo reports confirming its beneficial effects on bone formation. However, the use of electrical stimulation on Ti implants to enhance osseointegration is less understood, in part because of the lack of in vitro models that truly represent the in vivo environment.
Consequently, Ti implants with tailored surface properties such as nanotopography and electrical polarization could promote bone healing and osseointegration to ensure successful outcomes for patients by mimicking the biological environment of bone without the use of systemic drugs. The objective of this thesis is to understand how surface nanostructural and electrical properties of Ti and Ti alloy surfaces may affect osteoblast lineage cell response in vitro for normal tissue regeneration and repair. Our central hypothesis is that combined micro/nanostructured surfaces, as well as direct stimulation of Ti surfaces with fixed DC potentials can enhance osteoblast differentiation.
