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Effect of mullite–zircon addition on sintering and mechanical properties of hydroxyapatite
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Abstracts / Journal of Biomechanics 44 (2011) ee1–e21
An investigation on static behavior of dental implants with different loading locations and numbers of implants ¨ zyilmaz a, Halil Aykul a, Mehmet Dalkiz b, Emre O c Hatice Zehra Akbas- , H. Ali C - etinkara b,a a
Hitit University, Engineering Faculty, Turkey Mustafa Kemal University, Faculty of Dentistry, Turkey c Mustafa Kemal University, Science–Arts Faculty, Turkey b
The use of implants have revolutionized dental treatment modalities and provided excellent durable results. In evaluation of the long-term achievement of a dental implant, the reliability and the stability of the implant–abutment and implant–bone interfaces plays an essential role. Due to these reasons, we decided to make researches on implant stabilities on a human mandible model with the use of 6 and 10 implants. This numerical study was carried out using three-dimensional finite element method (FEM). Solid models of implants were built up in Solid Works and then transferred to a mesh model in FEM (ANSYS) to perform a stress analysis. According to analysis which was performed on the mandible and implant models we find out total deformations and equivalent stress results on human mandible with the loading which was applied on different locations and numbers of implant fixtures. With the help of these analyses, we tried to observe how to obtain the most suitable implant mandible fixtures with 6 or 10 implants. In addition, we’ll be able to make comments on choice of the type of implants and their location place.
Keywords: Finite element analysis; Dental implants; Prosthesis design; Fully edentulous; Mastication force doi: 10.1016/j.jbiomech.2011.02.042
Effect of mullite–zircon addition on sintering and mechanical properties of hydroxyapatite ¨ - uk ¨ c Recep Artır a, S- enol Avcı b, Israfil Kuc a
Marmara University, Faculty of Engineering, Metallurgical and Materials Engineering, Turkey b Bilecik University, Osmaneli Vocational School, Machine Programme, Turkey c Cumhuriyet University, Institute for Gradute Studies in Pure and Applied Sciences, Materials Division, Turkey
Hydroxyapatite (HAp) is used as a biomaterial especially as a coating material on the metallic substrates to take the advantages of both excellent biocompatibility of hydroxyapatite and good mechanical properties of the metals as well. However, the mechanical properties of HAp is not adequate and it can be improved by adding various reinforcement materials. In this study, HAp was reinforced with 25 mm mullite–zircon (3Al2O3 2SiO2–ZrSiO4) in different ranges from 0 up to 10 wt% and cylindrical samples were produced by uniaxial dry pressing at 10 MPa. After drying of samples at 110 1C for overnight sintering was performed at 1300 1C for 5 h in air to see the effects of various reinforcement percentages on the development of microstructure, mechanical and physical properties. Mechanical property of all samples were investigated by microhardness measurements.
Physical properties was also measured involving bulk density, apparent porosity, weight and volumetric changes. XRD analysis was also conducted after sintering to identify reaction products formed and finally optical microstructural examination was also performed. Improvement of mechanical properties of HAp was observed after sintering. As the amount of reinforcement rises particularly after 4 wt% addition up to 10 wt%, density and hardness values increase leading to microstructural development and improvement.
Keywords: Hydroxyapatite; Microhardness
Reinforcement;
Mullite;
Zircon;
doi: 10.1016/j.jbiomech.2011.02.043
Biomechanical analysis of percutaneous all lateral pinning (Dorgan’s technique) technique for supracondylar humerus fractures in children Kaya Memisoglu a, Resul Musaoglu a, Abdulkadir Cengiz b, Cumhur C. Kesemenli a a
Kocaeli University, School of Medicine, Department of Orthopaedics and Traumatology, Kocaeli, Turkey b Kocaeli University, School of Technical Education, Department of Mechanical Education, Kocaeli, Turkey We tried to compare biomechanical properties of all lateral pinning (Dorgan’s technique) with other pinning configurations used for humerus supracondylar fractures in children. In all lateral pinning technique iatrogenic nerve injury risk is minimized with secure fixation compared with other pin fixation configurations. Biomechanical testing was performed on 50 synthetic humeral bones (Keklikoglu). Transverse supracondylar humeral fractures were made with a hand-held saw above the olecranon fossa. Five different pin configurations were selected for fracture stabilization: 2 lateral pins and 1 medial pin (3 crossed), 2 laterally divergent pins, 2 crossed pins, 2 all laterally crossed pins (Dorgan’s technique), 2 laterally parallel pins. All the pin configurations were fluoroscopically confirmed. The fractures were stabilized with 0.06200 Kirschner wires. Biomechanical tests were performed by torsional load producing machine with internal rotation of the distal fragment. All the models were subjected to torsional loads for 10 times between 5 and 50 N and rotation in degrees and corresponding torques were recorded for statistical analysis. The differences of the stiffness of the pin configurations [2 lateral pins and 1 medial pin (3 crossed), 2 laterally divergent pins, 2 crossed pins, 2 all lateral crossed pins (Dorgan’s technique), 2 laterally parallel pins] were found, respectively, 0.06, 0.043, 0.039, 0.012 and 0.013 N m/degree. All lateral crossed pins (Dorgan’s technique) showed biomechanically equal properties to the medio-lateral, lower to the 2 lateral and 1 medial pin, and superior to the other pin configurations. All lateral crossed pins do not jeopardize the ulnar nerve during insertion of the pins percutaneously and fix the fracture with low learning curve.
Keywords: Supracondylar humerus fracture; Pinning; Biomechanical stability; Dorgan’s doi: 10.1016/j.jbiomech.2011.02.044
Abstracts / Journal of Biomechanics 44 (2011) ee1–e21
An investigation on static behavior of dental implants with different loading locations and numbers of implants ¨ zyilmaz a, Halil Aykul a, Mehmet Dalkiz b, Emre O c Hatice Zehra Akbas- , H. Ali C - etinkara b,a a
Hitit University, Engineering Faculty, Turkey Mustafa Kemal University, Faculty of Dentistry, Turkey c Mustafa Kemal University, Science–Arts Faculty, Turkey b
The use of implants have revolutionized dental treatment modalities and provided excellent durable results. In evaluation of the long-term achievement of a dental implant, the reliability and the stability of the implant–abutment and implant–bone interfaces plays an essential role. Due to these reasons, we decided to make researches on implant stabilities on a human mandible model with the use of 6 and 10 implants. This numerical study was carried out using three-dimensional finite element method (FEM). Solid models of implants were built up in Solid Works and then transferred to a mesh model in FEM (ANSYS) to perform a stress analysis. According to analysis which was performed on the mandible and implant models we find out total deformations and equivalent stress results on human mandible with the loading which was applied on different locations and numbers of implant fixtures. With the help of these analyses, we tried to observe how to obtain the most suitable implant mandible fixtures with 6 or 10 implants. In addition, we’ll be able to make comments on choice of the type of implants and their location place.
Keywords: Finite element analysis; Dental implants; Prosthesis design; Fully edentulous; Mastication force doi: 10.1016/j.jbiomech.2011.02.042
Effect of mullite–zircon addition on sintering and mechanical properties of hydroxyapatite ¨ - uk ¨ c Recep Artır a, S- enol Avcı b, Israfil Kuc a
Marmara University, Faculty of Engineering, Metallurgical and Materials Engineering, Turkey b Bilecik University, Osmaneli Vocational School, Machine Programme, Turkey c Cumhuriyet University, Institute for Gradute Studies in Pure and Applied Sciences, Materials Division, Turkey
Hydroxyapatite (HAp) is used as a biomaterial especially as a coating material on the metallic substrates to take the advantages of both excellent biocompatibility of hydroxyapatite and good mechanical properties of the metals as well. However, the mechanical properties of HAp is not adequate and it can be improved by adding various reinforcement materials. In this study, HAp was reinforced with 25 mm mullite–zircon (3Al2O3 2SiO2–ZrSiO4) in different ranges from 0 up to 10 wt% and cylindrical samples were produced by uniaxial dry pressing at 10 MPa. After drying of samples at 110 1C for overnight sintering was performed at 1300 1C for 5 h in air to see the effects of various reinforcement percentages on the development of microstructure, mechanical and physical properties. Mechanical property of all samples were investigated by microhardness measurements.
Physical properties was also measured involving bulk density, apparent porosity, weight and volumetric changes. XRD analysis was also conducted after sintering to identify reaction products formed and finally optical microstructural examination was also performed. Improvement of mechanical properties of HAp was observed after sintering. As the amount of reinforcement rises particularly after 4 wt% addition up to 10 wt%, density and hardness values increase leading to microstructural development and improvement.
Keywords: Hydroxyapatite; Microhardness
Reinforcement;
Mullite;
Zircon;
doi: 10.1016/j.jbiomech.2011.02.043
Biomechanical analysis of percutaneous all lateral pinning (Dorgan’s technique) technique for supracondylar humerus fractures in children Kaya Memisoglu a, Resul Musaoglu a, Abdulkadir Cengiz b, Cumhur C. Kesemenli a a
Kocaeli University, School of Medicine, Department of Orthopaedics and Traumatology, Kocaeli, Turkey b Kocaeli University, School of Technical Education, Department of Mechanical Education, Kocaeli, Turkey We tried to compare biomechanical properties of all lateral pinning (Dorgan’s technique) with other pinning configurations used for humerus supracondylar fractures in children. In all lateral pinning technique iatrogenic nerve injury risk is minimized with secure fixation compared with other pin fixation configurations. Biomechanical testing was performed on 50 synthetic humeral bones (Keklikoglu). Transverse supracondylar humeral fractures were made with a hand-held saw above the olecranon fossa. Five different pin configurations were selected for fracture stabilization: 2 lateral pins and 1 medial pin (3 crossed), 2 laterally divergent pins, 2 crossed pins, 2 all laterally crossed pins (Dorgan’s technique), 2 laterally parallel pins. All the pin configurations were fluoroscopically confirmed. The fractures were stabilized with 0.06200 Kirschner wires. Biomechanical tests were performed by torsional load producing machine with internal rotation of the distal fragment. All the models were subjected to torsional loads for 10 times between 5 and 50 N and rotation in degrees and corresponding torques were recorded for statistical analysis. The differences of the stiffness of the pin configurations [2 lateral pins and 1 medial pin (3 crossed), 2 laterally divergent pins, 2 crossed pins, 2 all lateral crossed pins (Dorgan’s technique), 2 laterally parallel pins] were found, respectively, 0.06, 0.043, 0.039, 0.012 and 0.013 N m/degree. All lateral crossed pins (Dorgan’s technique) showed biomechanically equal properties to the medio-lateral, lower to the 2 lateral and 1 medial pin, and superior to the other pin configurations. All lateral crossed pins do not jeopardize the ulnar nerve during insertion of the pins percutaneously and fix the fracture with low learning curve.
Keywords: Supracondylar humerus fracture; Pinning; Biomechanical stability; Dorgan’s doi: 10.1016/j.jbiomech.2011.02.044