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SAND blasting, TITANIUM fatigue, NANOPARTICLES, DEPOSITIONS, PROSTHETICS, and HYDROPHOBIC interactions

The physical properties of biocompatible titanium surfaces were modified using different techniques of surface treatment. Particularly the measurements of roughness and wetting ability were controlled using six different techniques: polishing, sandblasting, acid attack, laser ablation, ion implantation and nanoparticle deposition. The titanium surface wetting can be modified drastically depending on the used treatment to enhance the hydrophilic or the hydrophobic behaviour of the metallic biocompatible surface. The study demonstrates that a linear relation between roughness and contact angle occurs. Possible applications to permanent or removable prosthesis titanium based are presented and discussed. [ABSTRACT FROM AUTHOR]

ZIRCONIUM oxide, SURFACE preparation, BOND strengths, POLYCRYSTALS, and FRACTURE toughness

The effect of zirconia surface treatment by mesoporous zirconia coating on the microtensile bond strength (MTBS) between zirconia and resin cement was investigated in this work. 160 zirconia specimens were prepared and divided into four groups according to surface treatments: (1) airborne-particle-abrasion treatment (APA); (2) glass infiltration and hydrofluoric acid treatment (GI+HF); (3) mesoporous zirconia coating (MZ); and (4) no treatment (C). The as-prepared zirconia specimens were bonded using Panavia F2.0 and RelyX Unicem. The MTBS values were tested using a universal testing machine, and data were analyzed using ANOVA and SNK methods (α=0.05). The MTBS values obtained after GI+HF and MZ treatments were significantly higher than those obtained after APA and C treatments (P<0.05), especially for samples cemented with Panavia F2.0. The results reveal that zirconia surface treatments using GI+HF and MZ yield higher bond strength than those using APA or C, regardless of the resin cements. [ABSTRACT FROM AUTHOR]

TREATMENT of fractures, ORTHOPEDIC implants, STAINLESS steel, COBALT alloys, TITANIUM alloys, and BONE mechanics

Non-degradable metals such as stainless steel, cobalt-chromium-based alloys, titanium and its alloys may lead to stress shielding effect after fractured bone has healed. This complication may attribute to the non-degradability and the mismatch of the mechanical properties between these metallic implants and human bone. Biodegradable metallic materials have been therefore studied as alternative implantable metals in orthopaedics for some years. Magnesium is a potential candidate, as its mechanical properties are similar to human. Additionally, it is degradable and its ions are essential for cell functions. However, rapid degradation and release of hydrogen gas may inhibit its applications clinically. Hence, this paper reviews the development of the biodegradable metallic implants and various methods to improve the degradation of magnesium alloys. [ABSTRACT FROM AUTHOR]

ACOUSTIC emission, THERMAL barrier coatings, MATERIAL fatigue, PROCESS control systems, and RELIABILITY in engineering

Acoustic emission (AE) is a powerful tool to monitor the damage and impact in materials and structures. Process control is also one of the applications of AE measurement. However, it was very difficult to detect and analyze AE signals during material processing because of severe environment. Recently new technique to record AE signals such as laser AE and continuous waveform recording have been developed to apply to material processing. Ceramic thermal barrier coatings (TBCs) by atmospheric plasma spraying (APS) process have been widely used to add good heat resistance to metal base materials. Shot peening is also one of the surface treatment methods to improve the materials properties such as fatigue strength by shooting of balls on the surface of products in order to generate a compressive stress. However, there are a few researches on quantitative evaluation between shot conditions and mechanical properties of products, and the optimal process conditions are determined through a try and error process. AE signals were successfully detected and analyzed in surface treatment such atmospheric plasma spraying, high velocity oxy-fuel coating process and shot peening. Condition monitoring of material processing using AE will be promising to improve the reliability of materials and structures. [ABSTRACT FROM AUTHOR]

NANOTUBES, CARBON, TITANIUM, EXTRACELLULAR matrix proteins, and ADSORPTION

Carbon nanotubes (CNTs) have excellent chemical durability, mechanical strength and electrical properties. Therefore, there is interest in CNTs for not only electrical and mechanical applications, but also biological and medical applications. We coated titanium, a common material for dental implants, with multiwalled carbon nanotubes (MWCNTs). First, titanium was aminated and covered with collagen. Then, the carboxylated MWCNTs were coated onto the collagen attached to the titanium plate. The collagen-coated titanium plate had a homogeneous MWCNT coating, which showed strong attachment to the titanium surface as a thin layer. The surface roughness was significantly increased with the MWCNT coating. MC3T3-E1 cells were cultured on the MWCNT-coated Ti plate, and showed good cell proliferation and strong cell adhesion. Therefore, the MWCNT coating for titanium could be useful for improvement of cell adhesion on titanium implants. [ABSTRACT FROM AUTHOR]

TITANIUM, DENTAL implants, SURFACE analysis, TORQUE, CELL migration, BONE, and CELLS

The biological properties of commercial pure titanium (cp-Ti) dental implants can be improved by surface treatment. In this study, the cp-Ti surfaces were prepared to enable machined surfaces (TM) to be compared to the machined, sandblasted, laser irradiated and dual-acid etched surfaces (TA). The surface elements and roughness were characterized. The biocompatibility was evaluated by cell and organ culture in vitro. The removal torque was measured in rabbit implantation. Surface characterization revealed that TA surface was more oxidized than TM surface. The TA surface had micrometric, beehive-like coarse concaves. The average roughness (2.28 μm) was larger than that typical of acid-etched surfaces. Extracts of both materials were not cytotoxic to bone cells. The morphology of cells attached on the TA surface was superior to that on the TM surface. TA promoted cell migration and repaired damaged bones more effectively in organ culture. The formation of bone-like nodules on TA disk exceeded that on TM disk. Rabbit tibia implantation also proved that TA implant had greater removal torque value. These results suggested that TA had good osteoconductivity and was a potential material for dental implantation. [ABSTRACT FROM AUTHOR]

RESIDUAL stresses, STRAINS & stresses (Mechanics), DEFORMATIONS (Mechanics), LASERS, SHOT peening, METAL finishing, STRENGTH of materials, and SOLDER & soldering

This paper provides a summary of residual stress measurements performed in the development of a specific application of laser peening. Laser peening is an emerging surface treatment for metals that imparts compressive residual stress near the surface by introducing cold work. Since residual stress is a key outcome of the process, its measurement is an important process diagnostic. The first part of this work demonstrates the effects of specific laser peening process variations on the residual stress profile imparted to a corrosion-resistant nickel alloy (Alloy 22, UNS N06022). The second part of this work demonstrates measurements of a two-dimensional spatial distribution of the weld-direction residual sress component for a thick welded joint in the as-welded and laser peened conditions. [ABSTRACT FROM AUTHOR]

Hydrophobic and Hydrophilic Interactions, Surface Properties, Wettability, Biocompatible Materials chemistry, Prostheses and Implants, and Titanium chemistry

The physical properties of biocompatible titanium surfaces were modified using different techniques of surface treatment. Particularly the measurements of roughness and wetting ability were controlled using six different techniques: polishing, sandblasting, acid attack, laser ablation, ion implantation and nanoparticle deposition. The titanium surface wetting can be modified drastically depending on the used treatment to enhance the hydrophilic or the hydrophobic behaviour of the metallic biocompatible surface. The study demonstrates that a linear relation between roughness and contact angle occurs. Possible applications to permanent or removable prosthesis titanium based are presented and discussed.