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An Overview of Human Bone, Biomaterials and Implant Manufacturing
Published in Pankaj Agarwal, Lokesh Bajpai, Chandra Pal Singh, Kapil Gupta, J. Paulo Davim, Manufacturing and Industrial Engineering, 2021
Pradeep Singh, Pankaj Agarwal, I.B. Singh, D.P. Mondal
There are three main types of cells that are found in the bone, as shown in Figure 9.2. The first is the osteoblast which is responsible for the formation of bone. Bone resorption or destruction is caused due to the osteoclast and osteocytes cells, which are basically osteoblast restrained in the matrix of the bone for maintenance. Bone cells react according to the mechanical forces in the form of strain (Frost 1998). It is assumed that osteocytes work as the mechano-sensor that detects mechanical signals. At resting position (zero strain), the generation of osteoclast takes place, and this reduces bone density and resorbs the bone. At proper strain experienced by the osteocytes, osteoblast cells generate and strengthen the bone (Sims and Gooi 2008). The functioning of different cells of the bone and the restoration of new bone tissues are shown in Figure 9.2.
Hard Tissue Replacements
Published in Joyce Y. Wong, Joseph D. Bronzino, Biomaterials, 2007
Sang-Hyun Park, Adolfo Llinás, Vijay K. Goel, J.C. Keller
Load bearing and motion of the prosthesis produces wear debris from the articulating surface, and from the interfaces were there is micromotion, for example, stem–cement interface. Bone chip, cement chip, or broken porous coating are often entrapped in the articulating space and cause severe polyethylene wear (third-body wear). The principal source of wear under normal conditions is the UHMWPE bearing surface in the cup. Approximately 150,000 particles are generated with each step and a large proportion of these particles are smaller than 1 μm. Cells from the immune system of the host, for example, macrophages, are able to identify the polyethylene particles as foreign and initiate a complex inflammatory response. This response may lead to rapid focal bone loss (osteolysis), bone resorption, loosening, and/or fracture of the bone. Recently, low-wear UHMWPE has been developed using a cross-linking of polyethylene molecular chains. There are several effective methods of cross-linking polyethylene, including irradiation of cross-linking, peroxide cross-linking, and silane cross-linking [Shen et al., 1996]. However, none of the cross-linked polyethylene has been clinically tested yet. Numerous efforts are underway to modify the material properties of articulating materials to harden and improve the surface finish of the femoral head [Friedman, 1994]. There is growing interest in metal–metal and ceramic–ceramic hip prostheses as a potential solution to the problem of osteolysis induced by polyethylene wear debris.
Three-dimensional structural optimization of a cementless hip stem using a bi-directional evolutionary method
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Reza Rahchamani, Reza Soheilifard
The purpose of this study is to three dimensionally optimize the geometry of a cementless femoral implant using BESO method. The major advantages of the optimization in this work are the ability to create complex geometries with minimal constraints. The optimization is performed by minimizing the stress concentrations at the interface between the implant and the surrounding bone. A few studies in the literature had a similar objective (San Yoon et al. 1989; Kayabasi and Ekici 2007). Another important aspect to be investigated in a design of stem is bone remodelling in the periprosthetic bone. Bone remodelling is a physiological continuous process of bone resorption and formation for the purpose of maintaining normal bone mass. Proximal femoral bone loss reduces stem sustainability and may cause stem failure. In this study, long-term periprosthetic bone changes around the initial and the optimal stem are investigated using a bone remodelling theory.
Loading Psoralen into liposomes to enhance its stimulatory effect on the proliferation and differentiation of mouse calvarias osteoblasts
Published in Journal of Dispersion Science and Technology, 2019
Xiaoran Li, Vasil M. Garamus, Na Li, Zhe Zhe, Regine Willumeit-Römer, Aihua Zou
Osteoporosis is one of the most common human skeletal diseases, which could increase bone fragility and susceptibility to fracture since low bone-mass density and microarchitectural deterioration of bone tissue.[1,2] The National Osteoporosis Foundation (NOF) has been reported that approximately 10 million US adults aged 50 years and older had osteoporosis and an additional 33 million had low bone mass.[3,4] In China, the prevalence of osteoporosis has increased from 14.94% before 2008 to 27.96% during the period spanning 2012-2015, which affecting more than one-third of people aged 50 years and older.[5] Most osteoporosis is caused by increased bone resorption, many patients with osteoporosis have been treated with anti-resorptive drugs (estrogens, bisphosphonates, calcitonin), which could maintain bone mass by inhibiting osteoclast resorption.[6] However, the effect of these drugs on osteoblast formation and function is minor, no more than 2% per year for bone mass increase.[7] In addition, the potential complications also limited their usage for osteoporosis treatment.[8] Traditional Chinese herbal medicine have been widely used to treat osteoporosis for thousands of years, including Herba Epimedii,[9,10] Fructus Cnidii,[11] Tanshinone.[12]
Bone stress and damage distributions during dental implant insertion: a novel dynamic FEM analysis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Ahmet Emin Demirbas, Recep Ekici, Mustafa Karakaya, Alper Alkan
The rehabilitation of the edentulous jaws with the use of dental implants is a widespread and accepted treatment method that has well-documented and successful outcomes (Bozkaya et al. 2004; Schrotenboer et al. 2008). The biomechanics of dental implants play an important and major role in the long-term success of implant-supported prosthetic restorations (Hasan et al. 2014). The stress and strain occurring in the jawbone around the dental implant can be affected by some biomechanical factors such as quality and quantity of the jawbone, the loading type, macro and micro geometry of the implant, and surface properties of the implant (Staden et al. 2006). One of the main factors for the success of a dental implant is how the stresses are transferred to the surrounding jawbone (Geng et al. 2001). According to Wolff's theory, the bone's response to absorption or healing is directly related to stress in the bone (Wolff 1892). Also, according to Wolff's theory, bone remodeling is directly proportional to the forces acting on the bone (Wolff 1892; Monstaporn et al., 2020). These forces and stress especially cause crestal bone loss and are decisive in the success of the implant. The amount of bone loss in the neck area plays a role in determining the success of the implant (Wolff 1892; Ravishankar 2021; Monstaporn et al., 2020). Stresses around the dental implant can cause resorption of the jawbone. Especially, crestal bone loss around the dental implant can be observed in the short-term period after the implant insertion. Crestal bone loss occurs to a degree with all dental implant designs used clinically and it is mostly caused by excessive crestal bone stresses. This process results in the formation of a pocket around the neck region of the dental implant which can cause bacterial colonization and following tissue loss due to inflammation (Vaillancourt et al. 1995). The end of this process may result in a complete failure of the dental implant treatment. This bone resorption process which affects mainly the neck region of the dental implant can be activated also by surgical trauma, bacterial infections, functional forces and overloading at the bone-implant interface (Baggi et al. 2008).