Loading...
Search for:
dental-implants
0.007 seconds
The effect of microthread design on magnitude and distribution of stresses in bone: a three-dimensional finite element analysis
, Article Dental Research Journal ; Volume 15, Issue 5 , 2018 , Pages 347-353 ; 17353327 (ISSN) ; Eskandari, A ; Movahhedy, M. R ; Shirmohammadi, A ; Amid, R ; Sharif University of Technology
Abstract
Background: The researches regarding the influence of microthread design variables on the stress distribution in bone and a biomechanically optimal design for implant neck are limited. The aim of the present study is to compare the effect of different microthread designs on crestal bone stress. Materials and Methods: Six implant models were constructed for three-dimensional finite element analysis including two thread profile (coarse and fine) with three different lengths of microthreaded neck (1 mm, 2 mm, and 3 mm). A load of 200 N was applied in two angulations (0° and 30°) relative to the long axis of the implant and the resultant maximum von Mises equivalent (EQV), compressive, tensile,...
The Effect of Using a Viscoelastic Layer on a Dental Implant on the Stress/Strain Distribution at the Interface of Implant and Jaw Bone
, M.Sc. Thesis Sharif University of Technology ; Ahmadian, Mohammad Taghi (Supervisor) ; Firoozbakhsh, Keikhosrow (Supervisor)
Abstract
Natural teeth are connected to alveolar bone by periodontal ligaments ( PDL). PDL in addition to supporting tooth have the damping effect on transferring load from tooth to the surrounding bone. The most common replacement for a complete tooth loss is the use of Osseointegrated dental implants. The healthy bone remodeling and full bonding between bone and titanium surface of the implant is subjected to a successful osseointegration. The lack of PDLs in the structure of implant-bone system could lead to the failure of implant’s components due to overloading or to the impact loads. The aim of this study is to use viscoelastic material in the structure of dental implants to compensate for the...
Comparison of periodontally compromised splinted teeth and implant supported fixed partial denture: a three-dimensional finite element analysis on bone response
, Article Journal of long-term effects of medical implants ; Volume 31, Issue 2 , 2021 , Pages 1-8 ; 19404379 (ISSN) ; Kadkhodazadeh, M ; Talebi Ardakani, M. R ; Movahhedy, M. R ; Mirakhori, M ; Hakimi, A ; Broukhim, M ; Sharif University of Technology
NLM (Medline)
2021
Abstract
Introduction - This study aimed to compare the amount and pattern of stress and strain distributed around periodontally compromised splinted teeth and the two-implant abutments supported six-unit fixed partial denture (FPD) using finite element analysis (FEA). Methods and Materials - Six mandibular anterior teeth of a dental model were scanned and the scans were transferred to 3D CAD design and finite element software. Jaw bone was also designed and the teeth were splinted by fiber-reinforced composite (FRC) band. In another model, two implants were placed at the site of canine teeth and a six-unit FPD was designed over them. Models were transferred to finite element software and after...
In vitro biological outcome of laser application for modification or processing of titanium dental implants
, Article Lasers in Medical Science ; Volume 32, Issue 5 , 2017 , Pages 1197-1206 ; 02688921 (ISSN) ; Farahmand, F ; Tabatabaei, F. S ; Sharif University of Technology
Abstract
There are numerous functions for laser in modern implant dentistry including surface treatment, surface coating, and implant manufacturing. As laser application may potentially improve osseointegration of dental implants, we systematically reviewed the literature for in vitro biological responses to laser-modified or processed titanium dental implants. The literature was searched in PubMed, ISI Web, and Scopus, using keywords “titanium dental implants,” “laser,” “biocompatibility,” and their synonyms. After screening the 136 references obtained, 28 articles met the inclusion criteria. We found that Nd:YAG laser was the most commonly used lasers in the treatment or processing of titanium...
Effect of Fluorine Addition on Properties of Electrodeposited Fluorine-doped Hydroxyapatite Coating on AZ31 alloy
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
Magnesium and its alloys are potentialy biodegradable implant materials due to their attractive biological properties. But their poor corrosion resistance may result in sudden failure of the implants. Recently, many researchers have focused on applications of fluorine-doped hydroxyapatiteCa10(PO4)6(OH)2−xFx (FHA, x is the degree of fluoridation) as a bioactive coating to provide early stability and long-term performance. In comparison with pure HA coating,FHA coating could provide significant dissolution-resistant property, better apatite-like layer deposition, better protein adsorption, better cell attachment and improved alkaline phosphatase activity in cell culture. In this...
Fabrication of Dental Implant from Ti-6Al-4V With Nanostructured Hydroxyapatite Coating
, M.Sc. Thesis Sharif University of Technology ; Sadrnezhad, Khatiboleslam (Supervisor)
Abstract
The use of dental implants has grown considerably in recent years in Iran but this piece is the industrial imported parts that are not yet produced in Iran. So the main purpose of this research was to fabricate a dental implant from Ti-6Al-4V alloy by CNC machining techniques. On the other hand, the poor bonding strength of bioactive coatings and low cell growth on the surface of uncoated implants are the common problems in the use of dental implants. So another aim of this study was to investigate the effect of Nanoscale surface topography and nanostructured coatings on the surface modification of titanium implant in order to improve Osseointegration and the bonding strength of bioactive...
Loading of Drug and Nanostructured Coating on Dental Implant
, M.Sc. Thesis Sharif University of Technology ; Sadrnezhaad, Khatiboleslam (Supervisor)
Abstract
The aim of this project is to load analgesic drug; Paracetamol on dental implant. The implant is titanium alloy (Ti-6Al-4V). There are two kinds of samples of anodized and HA coated onto anodized. They are in the shape of the sheets in this study. The electrodeposition and anodization carried out in order to treat the two samples. Nanotubes were formed during anodic oxidation of the samples in the 1M Ammonium sulfate (NH₄)₂SO4 and 5wt% Ammonium fluoride NH4F electrolyte. They are expected to play role of carrier for the model drug; paracetamol. The results showed that HA anodized Ti-6-4 has the ability to hold higher amounts of drug and also can keep the drug for a longer time than the...
A Micromechanical Study of Implants via Eigenstrain Theory
, M.Sc. Thesis Sharif University of Technology ; Mohammadi Shodja, Hossein (Supervisor)
Abstract
In this thesis, concerning Eigenstrain Theory, the micromechanical formulation of dental implants has been derived for the first time in the fields of Mechanics and Medical Science. The proliferation of using dental implants as a prosthesis for the people who lost their teeth because of poor maintenance and smoking cigarette results in scientists think more about the design of these implants and their stress fields inside the mandible. It is crystal clear that these stress fields cause stress shielding, which is a phenomenon that brings about bone loss or decrement in the bone density. Hence, if we know the stress that is produced by the implants inside the mandible, we can optimize the...
Deep learning in periodontology and oral implantology: A scoping review
, Article Journal of Periodontal Research ; Volume 57, Issue 5 , 2022 , Pages 942-951 ; 00223484 (ISSN) ; Motamedian, S. R ; Pirayesh, Z ; Haiat, A ; Zahedrozegar, S ; Mahmoudinia, E ; Rohban, M. H ; Krois, J ; Lee, J. H ; Schwendicke, F ; Sharif University of Technology
John Wiley and Sons Inc
2022
Abstract
Deep learning (DL) has been employed for a wide range of tasks in dentistry. We aimed to systematically review studies employing DL for periodontal and implantological purposes. A systematic electronic search was conducted on four databases (Medline via PubMed, Google Scholar, Scopus, and Embase) and a repository (ArXiv) for publications after 2010, without any limitation on language. In the present review, we included studies that reported deep learning models' performance on periodontal or oral implantological tasks. Given the heterogeneities in the included studies, no meta-analysis was performed. The risk of bias was assessed using the QUADAS-2 tool. We included 47 studies: focusing on...
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) ; Ghanati, G ; Firoozbakhsh, K ; Ghanati, P ; Sharif University of Technology
2011
Abstract
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...
The Effect of Different SLS Parameters on the Density of Polymer-Metal Parts
, M.Sc. Thesis Sharif University of Technology ; Movahhedi, Mohammad Reza (Supervisor)
Abstract
Selective Laser Sintering (SLS) is one of the powder-based Additive Manufacturing (AM) technology in which parts built by CO2 laser. In this research work, Titanium-PMMA-Stearic Acid powders are mixed together to produce parts by Indirect Metal Laser Sintering (IMLS) method. The optimum process parameters such as energy density, Percentage composition of Titanium-PMMA and Scan Sintering are obtained by adopting the Taguchi method for getting the maximum density and minimum porosity. Experiments are planned by Taguchi’s Mix-L8 orthogonal array. According to the results obtained from this study, the percentage of combination Ti-PMMA and Energy density, respectively, are a major parameters that...
Design and Fabrication of Thermoelastic Nitinol Implant with Radius Variation for Denture Base Replacement
, M.Sc. Thesis Sharif University of Technology ; Sadrnezhad, Khatiboleslam (Supervisor)
Abstract
In this research to solve the problems related to titanium implants, a new type of dental implant was designed and fabricated by using shape memory and pseudoelasticity properties of porous nitinol alloys. The elastic modulus of this implant (equal to 0.8 GPa) is similar to the cancellous jaw bone (equal to 0.3-1 GPa) which causes a normal distribution of stress and prevents bone resorption. The current approach is use of radius variation to facilitate implant surgery. These radial changes are created by using one way shape memory effect. First, the implant enters the jaw cavity by decreasing the radius and after reaching the body temperature and restoring the initial shape, the radius of...
Nerve retraction during inferior alveolar nerve repositioning procedure: a new simple method and review of the literature
, Article The Journal of oral implantology ; Volume 41 , 2015 , Pages 391-394 ; 01606972 (ISSN) ; Saadat, S ; Moshiri, R ; Shahmirzad, S ; Hassani, A ; Sharif University of Technology
2015
Abstract
Nerve repositioning surgery is one of the treatments chosen for the patients with edentulous posterior atrophic mandible. Like any other treatments, this therapy has its advantages and disadvantages, indications and contraindications. The most important complication of this procedure is neurosensory disturbance. This problem may occur at different stages of the treatment. One common time when nerve damage happens is when the nerve is located outside the canal and drilling and insertion of the implant are performed. Accordingly, this report describes a simple and feasible method to retract and protect nerves outside the canal during the treatment of nerve transposition. This will reduce the...
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) ; 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
2010
Abstract
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...
Feasibility of Fabrication of Functionally Graded Titanium Dental Implants Using SLS Technique
, M.Sc. Thesis Sharif University of Technology ; Farahmand, Farzam (Supervisor) ; Movahhedy, Mohammad Reza (Supervisor)
Abstract
Dental implants should be biocompatible. This ability cause bone growth beside implant and increases stability of implant. Manufactoring method and materials used in implants are main parameters affectig biocompatibility of implants. Fabrication of functionally graded structures is a novel method to increase biocompatibility. Stress shielding is one of the main causes of failures in current dental implants. This phenomenon takes place due to different young modulus of dental implants and host bone. Pouros structures remedial this problem and implant’s young modulus comes closer to host bone. The aim of this project is to study feasibily of fabrication of functionally graded titanium dental...
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 ; Lafzi, A ; Raoofi, S ; Khademi, M ; Amid, R ; Movahhedy, M. R ; Torabi, H ; Sharif University of Technology
Abstract
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°...
Effect of oxidizing atmosphere on the surface of titanium dental implant material
, Article Journal of Bionic Engineering ; Volume 16, Issue 6 , 2019 , Pages 1052-1060 ; 16726529 (ISSN) ; Alizadeh, A ; Madaah Hosseini, H. R ; Sharif University of Technology
Springer
2019
Abstract
Direct oxidation is a simple and effective method for titanium surface treatment. In this research, a titanium sample was directly oxidized at the high temperature in two different atmospheres, air and pure oxygen, to obtain better atmosphere for titanium surface treatment. The results of the Raman spectroscopy indicated that in both atmospheres, the rutile bioactive phase (TiO2) has been formed on the titanium surface. The results of X-ray diffraction (XRD) also revealed that the surface of oxygen-treated sample was composed of the rutile phase and titanium monoxide (TiO), while at the surface of the air-treated sample, the rutile phase and titanium dioxide had been formed. Further, the...
Porous shape memory dental implant by reactive sintering of TiH2–Ni-Urea mixture
, Article Materials Science and Engineering C ; Volume 107 , 2020 ; Sadrnezhaad, S .K ; Hosseini, S. A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
We produced bifurcated bone-like shape memory implant (BL-SMI) with desirable tooth-root fixation capability by compact-sintering of TiH2–Ni-urea mixture. The primary constituents of the porous product were Ni and Ti. We could adjust the pores' shape, size, and interconnectivity for favorite bone ingrowth by using urea as a space holder. Without urea, we obtained an average porosity of 0.30, and a mean void size of 100 μm. With 70 vol % urea, we got 62% interconnected pores of 400 μm average size. Aging allowed us to tune the austenite-martensite transformation temperatures towards the needed body tissue arouse. Differential scanning calorimetry measured the transformation temperatures....
Niosomal formulation for antibacterial applications
, Article Journal of Drug Targeting ; Volume 30, Issue 5 , 2022 , Pages 476-493 ; 1061186X (ISSN) ; Gharehchelou, B ; Haghighi Poodeh, S ; Jamshidifar, E ; Karimifard, S ; Farasati Far, B ; Akbarzadeh, I ; Seifalian, A ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
Infection is a disease that is mainly caused by different Gram-negative and Gram-positive bacteria. Treatment of infections requires a considerable amount of antibiotics, which can cause serious damage to the patient's body. Delivering the antibiotic only to the site of infection can prevent these destructive effects, such as the destruction of the normal intestinal flora. The drug delivery system through carriers will take antibiotics into a part of the body involved in the disease. Niosome nanoparticles, which have been made from non-ionic surfactants, have been emerging as ideal drug/antibiotics delivery vehicles. Recently, niosome formulations have been targeted to reduce toxicity and...