Osteogenic properties of bioactive titanium in inflammatory environment.

Objectives: It is very important that the effects of surface modified titanium on osteogenic differentiation of bone marrow mesenchymal stem cells in the process of bone regeneration. The bio-function of modified titanium could be affected by the inflammatory micro-environment. The aim of this study was to investigate the effects of modified titanium on osteogenic differentiation in the inflammatory conditions and the osteogenic properties of the modified titanium dental implant in vivo.

Methods: The medical pure titanium metals (PT-Ti) subjected to Anodic Oxidation (AO-Ti), Sand Blasting/acid etching (SLA-Ti) and Plasma-sprayed HA coating (HA coating-Ti) were used for regulating the osteogenic properties of MSCs in the normal and inflammatory conditions.

Results: The amount of the MSCs in the inflammatory environment were more similar to that in the non-inflammatory environment after cultured on AO-Ti samples for 7D. However, the proliferation of the MSCs was obviously inhibited on the other groups in the inflammatory condition. The morphology of MSC cells on the modified titanium surface was affected in the inflammatory conditions and the AO-Ti was more conducive to maintain the skeletal morphology of MSCs. The results of osteogenic related proteins expression showed that the amount of BMP-2 on AO-Ti group was the highest in the inflammatory conditions, and followed the order of AO-Ti > HA coating-Ti > SLA-Ti > PT-Ti. What's more, the AO-Ti samples were more beneficial to promote the expression of osteogenic genes ALP, OCN, COL-I and Runx2 in the inflammatory conditions. The results of osteogenic properties in vivo showed that the gingival depth of the AO-Ti group was smaller than that on the other groups. Some new bone could be observed around the AO-Ti implant at two weeks. The bone binding rates on AO-Ti group was the highest of 81.3% after implanted for one year.

Significance: The AO-Ti was beneficial to osteogenic differentiation than other modified titanium metals in inflammatory condition. The anodic oxidation is an effective surface modification method on titanium to promote bone regeneration.