Advanced Materials Research Vol. 1114

Abstract: The purpose of our study was to compare the mechanical properties of the different abutment under the static loading, aspect treated by many researchers [1-4], especially following the improvements given by the new proposed three-piece abutment, described below. We evaluated the effect of compression loading on the screw joint stability of the two-piece abutment and a new proposed three-piece abutment connected to an internal hexagon implant in vitro.The dental implant used was type AlphaBio SPI with an internal hexagon shape with following dimensions: length 13mm and diameter 3.75mm. The two types of abutment were used: the common type consisting of two piece straight titanium abutment and the second type consisting of three piece abutment (two titanium pieces and the third piece made of UHMWPE). For two-piece titanium implant/abutment systems with a screw-retained connection, the respective prefabricated straight abutments were tightened with a torque gauge using titanium abutment screws (type M-TLA) according to the manufacturer’s instructions. In the second case, the first titanium piece was a connector base between the implant and the UHMWPE abutment body which is assembled all together with the implant abutment fixation screw. The experimental systems were positioned in bovine cortical bone with a central hole (3.75 mm in diameter), and mechanical characteristics were evaluated using mechanical tensile tests. The mechanical tensile tests were carried out using INSTRON 3382 tensile test equipment. All tensile tests were performed at a constant strain rate of 1mm/min until a maximum elongation of 4mm. Stress-strain tensile curves were obtained for each experimental system.There were significant differences in the case of using the system with three piece abutment and we could conclude that this type of abutment assure a lower pressing on the entire system due to the shock absorbent properties of the piece made by UHMWPE.

Abstract: Optimization of fractured or destroyed removable partial dentures realized from CoCrMo alloys are possible due to modern welding equipments. The aim of study was to offer the processing and welding optimal parameters for some long lasting prosthetic pieces. There are investigated two cobalt based alloys, used for dental applications, types CoCrMo. Laser welding equipments was a Mini Laser XXS (Orotig Italia) and the tested samples were welded in butt joint, without filler material. There are presented in comparison results concerning macro and micro structural analysis made on stereomicroscope OLYMPUS and Reichert microscope. Finally a correlation between different welding parameter values and structural features was made.

Abstract: Broad introduction and development of polymeric materials in abdominal hernia surgery led to the emergence and identification of secondary complications due to interaction between prosthetic material and human tissue. Whether identification of these reactions has led to the placement instructions of the prostheses into the wall structures of adbomen, there is no clear rule on fixation materials of these prosthesis; they generally follow the recommendations of the prosthesis materials.There are some situations in which the faulty choice of fixing materials can compromise such surgery, followed by chronic septic complications and negative effect on quality of life of these patients and increased risk of recurrence.The choice of fixing materials considering the structural characteristics of polymeric threads can prevent chronic suppuration secondary to this type of surgery.

Abstract: Total hip prosthese are widely used in total hip arthroplasty, offering many benefit to patients with different articular diseases like osteoarthritis or after different accidents. Many total hip prosthesis are now available to the orthopaedic surgeons to replace the hip articulation, with different design and with components made by different type of biomaterials: metallic (cobalt-chrome and titanium alloys, zirconium-niobium alloy named oxinium), ceramic (alumina, zirconia), polymers (ultra high weight molecular polyethylene-UHMWPE). Even total hip arthroplasty has a high success rate, implant loosening may occur, with different symptoms that could be attributed to metal allergy. Because the stem components of the total hip prosthesis are made by metallic biomaterials, many papers describe the adverse effects related to the release of metal ions (like cytotoxicity, carcinogenicity and metal allergy). There are different types of metal corrosion: intergranular, pitting, crevice, fatigue, stress, fretting, and galvanic. On the other hand, in many cases (like metal-on-metal prosthesis) appear corrosion and wear between two metallic components. This processes are favourable for the aparition of hypersensitivity-related tissue reactions. Especially some metallic ions (nickel, cobalt, and chromium) presents in stainless steels and cobalt-chromium alloys are most known to be released from prostheses components and give metal allergy. Of course, during the time was developped some solutions in order to improve the performance of the hip prostheses components made by metallic components like coating with thin layers using different biomaterials like porous titanium or hydroxiapatite. The aims of this review article were to explore mainly the relationship between corrosion products and implant-related hypersensitivity, the importance of surface treatment for metallic components, try define the effect of metal ion concentrations, and differentiate between allergy and infection in total hip replacement. The long-term performance of the coated components will be also analyzed and synthetic described based on clinical results. Also, some relevant aspects from our clinical experience and retrieved prosthesis analysis using stereomicroscopy and scanning electron microscopy will be shown in order to support the conclusions.