Youneng Xie

Improving the long-term stability of Ti6Al4V abutment screw by coating micro/nano-crystalline diamond films.

Abutment screw loosening is the most common complication of implanting teeth. Aimed at improving the long-term stability of them, well-adherent and homogeneous micro-crystalline diamond (MCD) and nano-crystalline diamond (NCD) were deposited on DIO(®) (Dong Seo, Korea) abutment screws using a hot filament chemical vapor deposition (HFCVD) system. Compared with bare DIO(®) screws, diamond coated ones showed higher post reverse toque values than the bare ones (p<0.05) after cyclic loading one million times under 100N, and no obvious flaking happened after loading test. Diamond coated disks showed lower friction coefficients of 0.15 and 0.18 in artificial saliva when countered with ZrO2 than that of bare Ti6Al4V disks of 0.40. Though higher cell apoptosis rate was observed on film coated disks, but no significant difference between MCD group and NCD group. And the cytotoxicity of diamond films was acceptable for the fact that the cell viability of them was still higher than 70% after cultured for 72h. It can be inferred that coating diamond films might be a promising modification method for Ti6Al4V abutment screws.

Micro/nano hierarchical structured titanium treated by NH4OH/H2O2 for enhancing cell response

In this paper, two kinds of titanium surfaces with novel micro/nano hierarchical structures, namely Etched (E) surface and Sandblast and etched (SE) surface, were successfully fabricated by NH4OH and H2O2 mixture. And their cellular responses of MG63 were investigated compared with Sandblast and acid-etching (SLA) surface. Scanning electron microscope (SEM), Surface profiler, X-ray photoelectron spectroscopy (XPS), and Contact angle instrument were employed to assess the surface morphologies, roughness, chemistry and wettability respectively. Hierarchical structures with micro holes of 10–30 μm in diameter and nano pits of tens of nanometers in diameter formed on both E and SE surfaces. The size of micro holes is very close to osteoblast cell, which makes them wonderful beds for osteoblast. Moreover, these two kinds of surfaces possess similar roughness and superior hydrophilicity to SLA. Reactive oxygen species were detected on E and SE surface, and thus considerable antimicrobial performance and well fixation can be speculated on them. The cell experiments also demonstrated a boost in cell attachment, and that proliferation and osteogenic differentiation were achieved on them, especially on SE surface. The results indicate that the treatment of pure titanium with H2O2/NH4OH is an effective technique to improve the initial stability of implants and enhance the osseointegration, which may be a promising surface treatment to titanium implant.

The Effects of Combined Micron-Scale Surface and Different Nanoscale Features on Cell Response

Sandblasting and acid-etching (SLA) and anodization are the two most commonly used methods for surface modification of biomedical titanium. However, there are unavoidable problems such as residual sand particles and lack of hydrophilicity on the surface of titanium sheets treated with SLA technology. In addition, titanium implants showed only the micro/submicroscopic structure. In order to avoid the residue of sand particles in the surface of titanium, the two surface treatments etching treatment (E) and etched-anodizing (EA) on titanium were used, and their surface topography, surface chemistry, and surface roughness were compared with those of the SLA control group. Their wettability and the biocompatibility were also compared and evaluated. The results show that both E and EA samples have the micro/nano hierarchical structure and better wettability compared with the SLA samples. Their performances, especially the E surfaces, were enhanced in terms of cell adhesion, spreading, proliferation, and differentiation abilities.