Patrik Prachár

Sensing of human plasma fibrinogen on polished, chemically etched and carbon treated titanium surfaces by diffractive optical element based sensor

Adsorption of human plasma fibrinogen (HPF) on 6 differently treated titanium samples (polished, polished and etched, and 4 titanium carbide coatings samples produced by using plasma-enhanced chemical vapour deposition (PECVD) method) is investigated by using diffractive optical element (DOE) sensor. Permittivity (susceptibility) change and fluctuation in optical roughness (R(opt)) of treated titanium surface in the presence of background electrolyte without and with HPF molecules are sensed by using DOE sensor and optical ellipsometry. Correlation between transmitted light and thickness of molecule layer was found. The findings allow to sense temporal organization and severity of adsorption of nano-scale HPF molecules on polished, on polished and etched, and on titanium carbide surface.

Fixed Bicortical Screw and Blade Implants as a Non-Standard Solution to an Edentulous (Toothless) Mandible

AimThis paper deals with the treatment of an atrophied toothless mandible with a fixing bridge carried by two non‐standard implant systems.MethodologyFour bicortical screws were implanted into the frontal part of the mandible and one implant on each side was placed into the distal area of the mandible as a support for a fixing bridge.ResultsDuring the years 2002 – 2007 the authors placed a total of 256 bicortical screw and 84 blade implants. During this period only four bicortical screws and one blade implant failed. The primary and secondary surgical success rate was therefore above 98%, while the prosthetic success rate was 100%. (Bridges which had to be re‐fabricated due to implant failure were not taken into account.)ConclusionThis approach is recommended as a highly successful and affordable option for a wide range of patients.

Cytocompatibility of implants coated with titanium nitride and zirconium nitride.

INTRODUCTION The positive cell response to the implant material is reflected by the capacity of cells to divide, which leads to the tissue regeneration and osseointegration. Technically pure titanium and its alloys are mostly used for implant manufacturing. These alloys have the adequate mechanical, physical and biological properties; nevertheless, the superior biocompatibility of bioceramics has been proven. With the arrival of new coating techniques, surface modification of materials used for implants has become a widely investigated issue. METHODS The paper studied properties of titanium nitride (TiN) and zirconium nitride (ZrN) coatings deposited by PVD (Physical Vapour Deposition). Coatings were applied to substrates of pure titanium, Ti6Al4V, Ti35Nb6Ta titanium alloys and CoCrMo dental alloy. Different treatments of substrate surfaces were used: polishing, etching and grit blasting. Cytocompatibility tests assessed the cell colonization and their adherence to substrates. RESULTS AND CONCLUSION Results showed that TiN layers deposited by PVD are suitable for coating all substrates studied. The polished samples and those with TiN coating exhibited a higher cell colonization. This coating technique meets the requirements for the biocompatibility of the implanted materials; furthermore, their colour range solves the issue of red aesthetics in oral implantology as the colour of these coatings prevents titanium from showing through the gingiva. This is one the most important criteria for the aesthetic success of implant therapy (Tab. 5, Ref. 18).

Optical Detection of Protein Adsorption on Doped Titanium Surface

The frequently used biomaterial in hard tissue replacement, such as dental and orthopaedic implants, is titanium. (Ball et al., 1996; Hook et al., 2002a; Huang et al., 2003; Imamura et al., 2008; Jones et al., 2000; Walivaara et al., 1994; Yang et al., 2003) These kind of biomaterial applications made of titanium are satisfactory products, because of their ability to adsorb certain proteins. After implantation, within a few seconds, the biomaterial surface becomes coated with a film of adsorbed proteins mediating the interaction between the implant and the body environment. Since an implant is exposed to blood during implantation, the initial protein layer is mainly composed of plasma proteins. Human plasma fibrinogen (HPF) is the relevant protein, which adsorbs on biomaterial surfaces. HPF partakes in blood coagulation, facilitates adhesion and aggregation of platelets (Cacciafesta et al., 2001; 2000). The structure and composition of the adsorbed protein layer determine the type and extent of the subsequent biological reactions, such as activation of coagulation and immune response and osseointegration (Nygren et al., 1997). Thus, the initially adsorbed protein layer is a factor determining the biocompatibility , and also in recent years interest has been focused to preparation of hydrocarbons doped with Ti and used different methods to analyzing of biocompatibility for important proteins . The production and application of doped titanium surfaces are under intensive research, and the results have shown the positive views on the adaptation of these materials as a biomaterial, as equal or even better than the bulk titanium. The doping of titanium is performed typically by inserting impurities like N, Nb, Zr, Ta, Al, Cr and V.

Mechanical properties and microstructure of Ti-35.5Nb-5.7Ta beta alloy

OBJECTIVE Titanium and titanium alloys represent generally accepted metallic biomaterials for clinical dentistry and dental implantology. In this paper, we present a Ti-35.5Nb-5.7Ta alloy with a special respect to its microstructure and mechanical characteristics, such as Young modulus of elasticity. METHODS Three thermal treatments differing in temperature and time of annealing were used during the Ti-35.5Nb-5.7Ta processing in order to evaluate the effects of ageing, melting annealing, and annealing on mechanical characteristics and microstructure. RESULTS Using microscopy, the alloy was analyzed and the differences in shares of beta phase grains, alpha particles and precipitates evaluated. The three thermal treatments were evaluated also from technological point of view. CONCLUSION The following thermal treatment was found optimal for the Ti-35.5Nb-5.7Ta alloy: melting annealing at 800 °C for 0.5 hour followed by a cold swaging with a 52-79 % deformation, and final hardening at 500 °C for 2 hours in water(Tab. 2, Fig. 3, Ref. 24).

The titanium PV I endosteal implant from beta-titanium alloy Ti 38Nb 6Ta.

AIM The aim of this study was to use the beta-titanium alloy Ti38Nb6Ta for production of a new construction line of implants, perform testing on animals and preclinical tests. MATERIALS AND METHODS Within this study, a new PV I implant with five construction variants was developed. The implant includes three types of threads - microthreads and flat threads of two types with a different depth. Further, the PV I implant was tested on minipigs. Subsequently, preclinical tests of 150 implants were performed and assessed. The age interval of patients was from 18 to 74 years. RESULTS Beta titanium alloy exhibited higher strength than titanium alloys. Anti-corrosion resistance was also higher. The implant from beta-alloy was inserted in the tibias of minipigs. Sections showed good osseointegration of the PV I implant. During the preclinical tests, 150 implants were inserted with the success rate of 99.33% after the two year assessment. The assessment also included handicapped patients who are not usually assessed in classical studies. Finally, the implantation protocol and documentation of a new implantation system PV I was designed. At the same time the industrial sample of this implant was formed and accepted. CONCLUSION A new anti-rotation PV I implant with microthreads and conical anchorage of the abutment into the fixture was formed. The beta-titanium alloy Ti38Nb6Ta used for the implant was biocompatible and had higher mechanical and physical properties than the existing titanium alloys. The PV I implant was recommended for clinical application.