The bone response of oxidized bioactive and non-bioactive titanium implants

Area of Science:

• Biomaterials Science
• Orthopedic Research
• Surface Chemistry

Background:

• Oxidized implants show promise, but the role of surface properties in osseointegration is not fully understood.
• Two proposed mechanisms for osseointegration are mechanical interlocking and biochemical bonding.
• The specific contribution of surface chemistry to osseointegration requires further investigation.

Purpose of the Study:

• To investigate the role of implant surface chemistry in bone responses.
• To validate the biochemical bonding theory for oxidized, bioactive bone implants with specific surface chemistry.

Main Methods:

• Two groups of oxidized implants were prepared using micro-arc oxidation: magnesium-incorporated (MgTiO) and TiO2 stoichiometry (TiO).
• Implants were inserted into rabbit bone for 6 weeks.
• Surface properties were analyzed, and bone responses were evaluated using removal torque and failure analysis.

Main Results:

• MgTiO implants demonstrated significantly higher removal torque values than TiO implants (p < 0.0001).
• Bonding failure for MgTiO implants occurred in the bone, while TiO implants showed failure at the bone-implant interface.
• Evidence of ionic movement and concentration gradients was detected between bone and MgTiO implant surfaces.

Conclusions:

• In vivo data support the surface chemistry-mediated biochemical bonding theory for oxidized bioactive implants.
• Magnesium incorporation into the oxide layer enhances osseointegration.
• Synergistic effects of oxide thickness, microstructure, crystal structure, and roughness may also influence bone responses.