Effects of Surface Topography of 3D Printed Titanium on Cell Behaviors

Objectives: Surface topography is one of the important factors, which influence dental implant osseointegration. However, the effects of surface topography of 3D printed dental implant on cells behaviors are not fully understood. To investigate the effects of surface topography of 3D printed titanium on cell behaviors, 3D printed titanium surfaces with different topography were created and analyzed in vitro.
Methods: Ti6Al4V powders with two sizes of 20 and 100 μm in average were used to print titanium discs using two methods: direct metal laser sintering (DMLS) and electron beam melting (EBM). Surface roughness and texture were measured by confocal microscope and SEM. Human stem cells with GFP label were cultured on the different surfaces of the discs for 1, 3, 7, 14 and 21 days. Cell morphology was examined by fluorescence microscope and SEM, and analyzed by imageJ.
Results: DMLS/20um had smallest surface roughness R_a, and EBM/100um had biggest R_a. EDX analysis revealed no difference among each groups. Cell morphology showed that there were multiple bubble structures in cells cultured on DMLS/20μm discs, but not on the discs of DMLS/100μm and EBM/100um. ImageJ analysis demonstrated that cell area at EBM/100um was larger than that at DMLS/20μm and DMLS/100μm groups. Cell circularity index at DMLS/20um group was smaller than that at DMLD/100um and EBM/100um.
Conclusions: 1, Powder size affects cell structure- small particles on the surfaces create bubble structure
2, Powder size affects cell morphology: cells cultured on the surfaces with small particles are more spindle, cells cultured on the surfaces with big particles are polygon and spreading
3, Surface texture has more effects on cell behaviors, while roughness has little impact on cell behaviors,
4, It is necessary to investigate the effects of titanium particle size of 3D printed titanium dental implants on osseointegration in vivo.