Beam srl is involved in several research projects dealing with surface engineering of
titanium devices.
It is well known that titanium is a successfully biocompatible material. Over the past three decades, the development of new processing methods has expanded the use of titanium in biomedical devices. In fact, continual improvements in both device design, surface treatments and clinical implantation techniques, have led to well-accepted titanium made prosthetic joints, surgical splints, stents and fasteners, dental implants, dental crowns and partial denture frameworks. Titanium biocompatibility of dental implant permits close apposition of physiological fluids, proteins and hard and soft tissues to the metal surface.
This process, whereby living tissue and an implant become structurally and functionally
connected, is called osseointegration.
Cold plasma treatments
Plasma is defined as a quasi-neutral ionized gas. It is constituted by particles in permanent interaction; the particles include photons, electrons, positive and negative ions, atoms, free radicals and excited or non-excited molecules. Cold plasmas are used to modify several kinds of materials from metallic to polymeric ones.
Some kinds of plasmas may have a general oxidative effect on the cell surface layers of microorganisms, inhibiting growth. Microbial colonization on metallic and ceramic implant materials has been reported in vitro and in vivo tests. Since commercial pure titanium, used in biomedical industry, does not have antibacterial activity, there is a probable risk of plaque formation on its surface, even if has been reported that anatase titanium oxide, formed on implant surface, has some germicidal activity. Antibacterial activity of titanium mplants could be a useful property to maintain plaque free surfaces exposed to oral cavity,
preventing peri-implantitis. Some electrochemical techniques have been studied to coat the titanium surface with an antibacterial layer, but they are harmful to the environment and require long treatment.
Beam srl has developed a process in which cold plasma treatment imposes antibacterial activity to titanium, using a “short” and environmental friendly treatment.
Nanostructured materials
Nanostructural titania (TiO 2 ), such as nanowires, nanofibers, nanorods, nanoribbons, nanoplates and nanotubes, are widely studied materials due to their unique and excellent properties in optics, electronics, photochemistry and biology, as well as their applications in photovoltaic cells, photocatalysis, and sensors due to the attractive architecture that offers a large surface area and a high structural order and several authors have demonstrated that is possible to produce nanotubes array by anodizing titanium flat specimens. A variety of electrolytes have been used to prepare TiO2 nanotubes, showing that their geometrical features are controlled by some parameters including anodization potential, electrolyte composition and properties thereof (primarily conductivity and viscosity), as well as anodization duration and cell temperature. Additionally, materials with aligned nanostructure are of great interest for application in molecular filtration, drug delivery and tissue engineering. Titanium is broadly used in orthopedic and dental application for its biocompatibility and optimal mechanical properties in load-bearing application, however, insufficient new bone formation is frequently observed on titanium
which, sometimes, leads to implant loosening and failure. Titania nanotubes array, formed by anodic oxidation, could be a simple method to modify the surface of titanium implants to enhance bone-forming function thereby increasing orthopedic and dental implant efficacy.
The aim of our research is devoted to the use of a simple experimental set-up, to create a uniform distribution of TiO 2 nanotubes array on samples of complex geometry. We would to emphasize the importance of this finding that not only expresses a technological innovation but opens new perspectives in testing medical devices.
Surface engineering
It is widely known that the peculiarity of titanium and its alloys is that it is covered with an
oxide layer that forms spontaneously when the material is in contact with the air.
Hydrofluoric acid may be used to remove the oxide layer, to obtain a surface free of oxide, even if often, in the industrial field, the treatment is made using hydrochloric acid that is less hazardous. Usually the acid process is followed by immersion of the devices in nitric acid or mixtures thereof.
In order to optimize the surface characteristics of dental implants, in function of their application, several types of surface treatments, have been proposed to improve its bioactivity, ranging from methods to change the roughness to those that provide the formation of bioactive surfaces, etc .. Several studies show that physical and/or chemical
treatments affect, both, the rate of osseointegration and the biomechanical properties. Roughness seems to be the most effective. In order to characterize the roughness of the dental implants, especially in the commercial field, it is used the parameter called “average roughness” Ra, but it does not describe the shape of the surface.
There are various other roughness parameters, like Sa, Sq, Sku e Ssk, that define the topography of the device in a unique manner.