Search for: dental-prostheses
0.008 seconds

    The dynamic analysis of a novel dental implant with a viscoelastic internal damping layer

    , Article 2010 17th Iranian Conference of Biomedical Engineering, ICBME 2010 - Proceedings, 3 November 2010 through 4 November 2010 ; November , 2010 ; 9781424474844 (ISBN) Ahmadian, M. T ; Firoozbakhsh, K ; Ghanati, G ; Isfahan University of Medical Sciences; Iranian Society of Biomedical Engineering; Medical Image and Signal Processing Research Center (MISP) ; Sharif University of Technology
    Conventional tooth implants lacks the damping prosperities of the periodontal ligaments (PDL) compound. It may therefore, disrupts the natural function of implant and leads to excessive stress and strain in jaw bone. Our new proposed implant has the viscoelastic properties needed to overcome such difficulties. A three dimensional finite element model of modified implant was developed and was subjected to dynamic loading condition. Our results so far indicate that the use of a class of material exhibiting viscoelastic behaviour as a damping layer can reduce the peak stress and displacement deduced from cyclic and impact loads. The stress distribution becomes more uniform in the alveolar crest... 

    Comparison of the effects of different implant apical designs on the magnitude and distribution of stress and strain in bone: A finite element analysis study

    , Article Journal of Long-Term Effects of Medical Implants ; Vol. 24, issue. 2-3 , 2014 , p. 109-120 Kadkhodazadeh, M ; Lafzi, A ; Raoofi, S ; Khademi, M ; Amid, R ; Movahhedy, M. R ; Torabi, H ; Sharif University of Technology
    Objectives: The aim of this study was to investigate the effects of implant design on the apex area and on stress and stress patterns within surrounding bone. Methods: Three commercially available implants with the same diameter (3.5 mm), same length (10-11 mm), and same complement abutment were selected for modeling as follows: (1) flat apical design with light tapering degree, (2) dome-shaped apical design with light tapering, and (3) flat apical design with intense tapering in one-third of the apical area. According to human cone-beam computed tomography (CBCT), the bone was modeled using a cortical thickness of 2 mm and cancellous bone. Forces of 100 N and 300 N in the vertical and 15°... 

    Synthesis and characterization of bioactive glass/forsterite nanocomposites for bone and dental implants

    , Article Ceramics - Silikaty ; Volume 56, Issue 4 , 2012 , Pages 331-340 ; 08625468 (ISSN) Kamalian, R ; Yazdanpanah, A ; Moztarzadeh, F ; Ravarian, R ; Moztarzadeh, Z ; Tahmasbi, M ; Mozafari, M ; Sharif University of Technology
    In this research, bioactive glass (BG) of the type CaO-P2O 5-SiO2 and nanocrystalline forsterite (NF) bioceramic were successfully synthesized via sol-gel processing method. Heat-treatment process was done to obtain phase-pure nanopowders. After characterization of each sample, the nanocomposite samples were prepared by cold pressing method and sintered at 1000°C. The samples were fully characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR) analyses. The average nanocrystallite size was determined using the Debye-Scherrer's formula 19.6 nm. The bioactivity was examined in vitro... 

    Influence of mechanical and chemical surface treatments on the formation of bone-like structure in cpTi for endosseous dental implants

    , Article Applied Surface Science ; Volume 259 , 2012 , Pages 283-287 ; 01694332 (ISSN) Parsikia, F ; Amini, P ; Asgari, S ; Sharif University of Technology
    Commercially pure titanium samples were exposed to grit blasting and acid-alkali treatments to obtain a variety of surface compositions and morphologies. Contact roughness test and microstructural studies were employed to study the surface topography of the samples. The nature and chemical composition of surface phases were evaluated using X-ray diffraction and microanalysis techniques. Selected samples first exposed to in vitro environment were then tested to determine the surface morphology and surface microstructure. Based on the data presented in this work, it is suggested that grit blasting process utilized prior to chemical treatment stage, yields a high quality surface morphology.... 

    The nonlinear finite element analysis of a novel dental implant with an interposed internal layer imitating periodontal ligament's function

    , Article ASME 2011 International Mechanical Engineering Congress and Exposition, IMECE 2011, 11 November 2011 through 17 November 2011 ; Volume 2 , November , 2011 , Pages 543-548 ; 9780791854884 (ISBN) Ahmadian, M. T ; Ghanati, G ; Firoozbakhsh, K ; Ghanati, P ; Sharif University of Technology
    Osseointegrated dental implants are deficient in natural periodontal ligaments. It may therefore, disrupts the natural function of implant and leads to excessive stress and strain in jaw bone. Our new proposed implant has the nonlinear internal component which imitates periodontal ligaments function. A nonlinear finite element analysis developed to investigate the efficiency of utilizing this nonlinear internal layer for three conditions of bone implant interface conditions under vertical and horizontal loading conditions. Our results so far indicate that the use of a class of material exhibiting incompressible hyperelastic behaviour as a internal layer can reduce the peak stress deduced... 

    Highly-ordered TiO2 nanotubes decorated with Ag2O nanoparticles for improved biofunctionality of Ti6Al4V

    , Article Surface and Coatings Technology ; Volume 349 , 2018 , Pages 1008-1017 ; 02578972 (ISSN) Sarraf, M ; Dabbagh, A ; Abdul Razak, B ; Mahmoodian, R ; Nasiri Tabrizi, B ; Madaah Hosseini, H. R ; Saber Samandari, S ; Abu Kasim, N. H ; Abdullah, H ; Sukiman, N. L ; Sharif University of Technology
    Elsevier B.V  2018
    The nanotubular arrays of titanium dioxide (TiO2 NTs) have recently received considerable interest for fabrication of dental and orthopedic implants. However, their antibacterial activity requires substantial improvement for the potential infections minimization, without compromise of their biocompatibility. In this work, TiO2 NTs were developed on Ti6Al4V substrates via anodization at a constant potential of 60 V for 60 min, followed by heat treatment at 500 °C for 90 min. Physical vapor deposition (PVD) was further employed to decorate silver oxide nanoparticles (Ag2O NPs) on the nanotubular edges. The results indicated that the highly-ordered TiO2 NTs with decorated Ag2O NPs could promote... 

    Biomechanical response of intact, degenerated and repaired intervertebral discs under impact loading – Ex-vivo and In-Silico investigation

    , Article Journal of Biomechanics ; Volume 70 , March , 2018 , Pages 26-32 ; 00219290 (ISSN) Nikkhoo, M ; Wang, J. L ; Parnianpour, M ; El-Rich, M ; Khalaf, K ; Sharif University of Technology
    Elsevier Ltd  2018
    Understanding the effect of impact loading on the mechanical response of the intervertebral disc (IVD) is valuable for investigating injury mechanisms and devising effective therapeutic modalities. This study used 24 porcine thoracic motion segments to characterize the mechanical response of intact (N = 8), degenerated (Trypsin-denatured, N = 8), and repaired (Genepin-treated, N = 8) IVDs subject to impact loading. A meta-model analysis of poroelastic finite element simulations was used in combination with ex-vivo creep and impact tests to extract the material properties. Forward analyses using updated specimen-specific FE models were performed to evaluate the effect of impact duration. The... 

    Effect of microthread design of dental implants on stress and strain patterns: A three-dimensional finite element analysis

    , Article Biomedizinische Technik ; Volume 58, Issue 5 , September , 2013 , Pages 457-467 ; 00135585 (ISSN) Amid, R ; Raoofi, S ; Kadkhodazadeh, M ; Movahhedi, M. R ; Khademi, M ; Sharif University of Technology
    Walter de Gruyter and Co  2013
    The aim of this study was to use finite element analysis (FEA) to assess the influence of microthread design at the implant neck on stress distribution in the surrounding bone. A commercially available implant with 3.5 mm diameter and 10.5 mm length was selected and used as a model. For the purpose of designing the microthread implant model, microthreads were added to the implant neck in a computerized model. A force measuring 100 N was then applied to the entire surface of the abutment in the vertical direction. The results showed that in both models, stress was mainly concentrated at the cortical bone adjacent to the neck of the implant. Maximum stress values in the cortical bone... 

    A foreign body response-on-a-chip platform

    , Article Advanced Healthcare Materials ; Volume 8, Issue 4 , 2019 ; 21922640 (ISSN) Sharifi, F ; Htwe, S. S ; Righi, M ; Liu, H ; Pietralunga, A ; Yesil Celiktas, O ; Maharjan, S ; Cha, B. H ; Shin, S. R ; Dokmeci, M. R ; Vrana, N. E ; Ghaemmaghami, A. M ; Khademhosseini, A ; Zhang, Y. S ; Sharif University of Technology
    Wiley-VCH Verlag  2019
    Understanding the foreign body response (FBR) and desiging strategies to modulate such a response represent a grand challenge for implant devices and biomaterials. Here, the development of a microfluidic platform is reported, i.e., the FBR-on-a-chip (FBROC) for modeling the cascade of events during immune cell response to implants. The platform models the native implant microenvironment where the implants are interfaced directly with surrounding tissues, as well as vasculature with circulating immune cells. The study demonstrates that the release of cytokines such as monocyte chemoattractant protein 1 (MCP-1) from the extracellular matrix (ECM)-like hydrogels in the bottom tissue chamber...