Effect of magnetic field on the fibronectin adsorption, cell attachment and proliferation on titanium surface.

OBJECTIVES: We studied the effect of various static magnetic fields (SMFs) on the adsorption of specific recombinant fibronectin (FN) peptide (hFNIII9-10) on the titanium surface. Furthermore, the responses of human osteosarcoma TE-85 cells in the SMF were observed. MATERIAL AND METHODS: Various magnetic fields--1, 2, 3, 5, 7, 10 mT--were established by controlling the distance from Nd-Fe-B magnet to the disks. For FN adsorption experiment, machined titanium disks were incubated in 1 microM hFNIII9-10 at 37 degrees C overnight under magnetic field. The adsorbed hFNIII9-10 was measured as optical density (OD). For attachment study, TE-85 cells were incubated for 2 h on the hFNIII9-10 coated machined titanium disks and OD values were measured. As for proliferation study, titanium disks were incubated for 48 h after washing unattached cells in 2 h. The amount of proliferated TE-85 cell was also measured as OD value. Attachments of TE-85 cells under various intensities of magnetic field were observed using a scanning electron microscope. RESULTS: The amount of adsorbed hFNIII9-10 showed no significant difference between control (0 mT) and six experimental groups (1, 2, 3, 5, 7, 10 mT). However, TE-85 cells attached significantly higher in groups of 1, 2, 5, 10 mT than in control group (P=0). Cell attachment in groups of 3, 7 mT showed no significant difference with that of control group. TE-85 cells were observed to attach through filopodia. Especially in 1 mT, flattened cells were predominant. In proliferation assay, 1 mT stimulated TE-85 cells showed significantly higher proliferation than those in 2, 3 and 7 mT (P=0). CONCLUSION: Magnetic fields under 10 mT did not influence FN adsorption on the titanium surface. However, a significant effect was found on cell attachment and proliferation.

Microarray-based expression analysis of human osteoblast-like cell response to anodized titanium surface.

An anodized surface significantly enhanced the adhesion of human osteoblast-like MG-63 cells to titanium. Using cDNA microarray analysis, five genes were differentially expressed while the rest remained unaltered. The results demonstrated that the anodized surface enhances cellular adhesion without significantly affecting the pattern of gene expression.

A histomorphometric analysis of the effects of various surface treatment methods on osseointegration.

PURPOSE: One major factor in the success and biocompatibility of an implant is its surface properties. The purposes of this study were to analyze the surface characteristics of implants after blasting and thermal oxidation and to evaluate the bone response around these implants with histomorphometric analysis. MATERIALS AND METHODS: Threaded implants (3.75 mm in diameter, 8.0 mm in length) were manufactured by machining a commercially pure titanium (grade 2). A total of 48 implants were evaluated with histomorphometric methods and included in the statistical analyses. Two different groups of samples were prepared according to the following procedures: Group 1 samples were blasted with 50-microm aluminum oxide (Al2O3) particles, and group 2 samples were blasted with 50-microm Al2O3, then thermally oxidized at 800 degrees C for 2 hours in a pure oxygen atmosphere. A noncontacting optical profilometer was used to measure the surface topography. The surface composition of the implants used and the oxide thickness were investigated with Rutherford backscattering spectrometry. RESULTS: The different preparations produced implant surfaces with essentially similar chemical composition, but with different oxide thickness and roughness. The morphologic evaluation of the bone formation revealed that: (1) the percentage of bone-to-implant contact of the oxidized implants (33.3%) after 4 weeks was greater than that of the blasted group (23.1%); (2) the percentages of bone-to-implant contact after 12 weeks were not statistically significantly different between the groups; (3) the percentages of bone area inside the thread after 4 weeks and 12 weeks were not statistically significantly different between groups. DISCUSSION AND CONCLUSION: This investigation demonstrated the possibility that different surface treatments, such as blasting and oxidation, have an effect on the ingrowth of bone into the thread. However, the clinical implications of surface treatments on implants, and the exact mechanisms by which the surface properties of the implant affect the process of osseointegration, remain subjects for further study.