Artykuły w czasopismach na temat „Artificial implants”
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Marchewka, M., i J. Zubrzycki. "Construction aspects of intraocular artificial lenses". Journal of Physics: Conference Series 2412, nr 1 (1.12.2022): 012011. http://dx.doi.org/10.1088/1742-6596/2412/1/012011.
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Abstract A cataract is a disease of the 21st century. In highly developed countries, the opacification of the intraocular lens is removed and replaced with an implant. This article discusses the essential aspects related to the construction of implants that imitate the natural lens of the eyeball. The research was carried out owing to X-ray microtomography. Observer design differences in the two lenses' structures contribute to the implant's quality in question. The study aimed to check and compare two types of implants in terms of the design and manufacturing quality of the given lenses. The common element of the implants in question was their material and manufacturer. Lenses of the same material were used to maintain the same optics. The results gave a comparison in terms of the quality of the product in terms of the creation and modelling of the lenses than the properties of the material itself from which they were made.
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Bowers, Christian A., Jaron H. McMullin, Cameron Brimley, Linsey Etherington, Faizi A. Siddiqi i Jay Riva-Cambrin. "Minimizing bone gaps when using custom pediatric cranial implants is associated with implant success". Journal of Neurosurgery: Pediatrics 16, nr 4 (październik 2015): 439–44. http://dx.doi.org/10.3171/2015.2.peds14536.
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OBJECT Occasionally after a craniotomy, the bone flap is discarded (as in the case of osteomyelitis) or is resorbed (especially after trauma), and an artificial implant must be inserted in a delayed fashion. Polyetheretherketone (PEEK) implants and hard-tissue replacement patient-matched implants (HTR-PMI) are both commonly used in such cases. This study sought to compare the failure rate of these 2 implants and identify risk factors of artificial implant failure in pediatric patients. METHODS This was a retrospective cohort study examining all pediatric patients who received PEEK or HTR-PMI cranioplasty implants from 2000 to 2013 at a single institution. The authors examined the following variables: age, sex, race, mechanism, surgeon, posttraumatic hydrocephalus, time to cranioplasty, bone gap width, and implant type. The primary outcome of interest was implant failure, defined as subsequent removal and replacement of the implant. These variables were analyzed in a bivariate statistical fashion and in a multivariate logistic regression model for the significant variables. RESULTS The authors found that 78.3% (54/69) of implants were successful. The mean patient age was 8.2 years, and a majority of patients were male (73%, 50/69); the mean follow-up for the cohort was 33.3 months. The success rate of the 41 HTR-PMI implants was 78.1%, and the success rate of the 28 PEEK implants was 78.6% (p = 0.96). Implants with a bone gap of > 6 mm were successful in 33.3% of cases, whereas implants with a gap of < 6 mm had a success rate of 82.5% (p = 0.02). In a multivariate model with custom-type implants, previous failed custom cranial implants, time elapsed from previous cranioplasty attempt, and bone gap size, the only independent risk factor for implant failure was a bone gap > 6 mm (odds ratio 8.3, 95% confidence interval 1.2–55.9). CONCLUSIONS PEEK and HTR-PMI implants appear to be equally successful when custom implantation is required. A bone gap of > 6 mm with a custom implant in children results in significantly higher artificial implant failure.
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Lambert, Lorraine. "Artificial Hair Implants". International Society of Hair Restoration Surgery 6, nr 5 (wrzesień 1996): 9.2–9. http://dx.doi.org/10.33589/6.5.9b.
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Inoue, Takashi. "The development of an artificial protein for periodontal application". Impact 2018, nr 3 (15.06.2018): 79–81. http://dx.doi.org/10.21820/23987073.2018.3.79.
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Most artificial implants in medicine are purely mechanical. They do not harness the natural biology, merely co-exist alongside it. This is no different in dentistry where false teeth tend not to interact with the biology of the mouth. Inoue and his team are developing bio-hybrid dental implants that are capable integrating themselves into the jawbone. The new implant will be more stable and long-lasting as well as being able to replicate the function and feel of natural teeth. They also have the crucial ability of being able to adapt to the restructuring in the jawbone that occurs as children age. Children's adult teeth must be able to move as the jawbone grows and adapt to new positions. Inoue summarises the issues surrounding dental implants: 'At present, dental implants are connected directly to the alveolar bone, with no mediation by periodontal tissues. It must be remembered, however, that these tissues play an important role not only in tooth support, but also in maintaining various physiological functions, including sensation and the tooth movement that usually accompanies bone remodelling.' The implant designed by Inoue and his team is based on a standard titanium core, but is enhanced in several different ways. The implant is coated in hydroxyapatite (HA), a mineral found in high concentrations in dentin and that is known to help stimulate bone growth. This basic implant is transplanted with a mixture of periodontal tissue extracted from another tooth. Together, HA and the periodontal tissue work together to promote true ossointegraton and the creation of a bio-hybrid implant. In experiments with young mice, the implant has been shown to integrate fully in the jaw and move as and when necessary during development, just like a normal tooth. In addition to these benefits, the novel hybrid actually maintains the ability of the tooth to sense noxious stimuli – something no current implant can do.
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Mohammadi, Bijan, Zahra Abdoli i Ehsan Anbarzadeh. "Investigation of the Effect of Abutment Angle Tolerance on the Stress Created in the Fixture and Screw in Dental Implants Using Finite Element Analysis". Journal of Biomimetics, Biomaterials and Biomedical Engineering 51 (14.06.2021): 63–76. http://dx.doi.org/10.4028/www.scientific.net/jbbbe.51.63.
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Today, an artificial tooth root called a dental implant is used to replace lost tooth function. Treatment with dental implants is considered an effective and safe method. However, in some cases, the use of dental implants had some failures. The success of dental implants is influenced by several biomechanical factors such as loading type, used material properties, shape and geometry of implants, quality and quantity of bone around implants, surgical method, lack of rapid and proper implant surface's integration with the jaw bone, etc. The main purpose of functional design is to investigate and control the stress distribution on dental implants to optimize their performance. Finite element analysis allows researchers to predict the stress distribution in the bone implant without the risk and cost of implant placement. In this study, the stresses created in the 3A.P.H.5 dental implant's titanium fixture and screw due to the change in abutment angles tolerance have been investigated. The results show that although the fixture and the screw's load and conditions are the same in different cases, the change of the abutment angle and the change in the stress amount also made a difference in the location of maximum stress. The 21-degree abutment puts the fixture in a more critical condition and increases the chance of early plasticization compared to other states. The results also showed that increasing the abutment angle to 24 degrees reduces the stress in the screw, but decreasing the angle to 21 degrees leads to increased screw stress and brings it closer to the fracture.
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Walter, Peter. "Implants for artificial vision". Expert Review of Ophthalmology 4, nr 5 (październik 2009): 515–23. http://dx.doi.org/10.1586/eop.09.42.
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Earar, Kamel, Ioan Sirbu, Ctristian Onisor i Elena Luca. "Oral Rehabilitation on Implants and Introduction of Pathogenic Mechanisms in Relation to Oral Implants - Sugar Diabetes". Revista de Chimie 70, nr 10 (15.11.2019): 3750–52. http://dx.doi.org/10.37358/rc.19.10.7639.
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Dental implants are made of medical titanium and perfectly fit into human bone tissue; the dental implant can last a lifetime. Not beeing living organic structures, there are no nerve endings, neither at the implant level nor at the artificial crown level. The use of quality implants by an experienced implantologist, assisted by advanced technology, transforms the treatment with dental implants into the medical-surgical act with the highest success rate among dental and even medical treatments.Through the complete replacement of the tooth, including the root, can artificially reproduce the function of the natural tooth, with a strong and stable base. The implant crown, made of aesthetic materials (porcelain, zirconium) and anchored to it by means of the prosthetic abutment, will be surrounded by a healthy and aesthetic gum. Especially if the prosthetic abutment (the connecting element between the implant itself and the artificial crown) will be made of zirconium - natural light will cross ceramic layers, similar to enamel and dentine, offering a white of envy and glitter to the smile. Around the porcelain crowns (whole ceramics or zirconia ceramics) the gingiva will conform healthily, without the slightest sign of inflammation. These elements, the white of the teeth and the pink of the gums define the concept of dental aesthetics. The main problems that diabetic patients may encounter, are gingival inflammation and periodontal disease, dental mobility and tooth loss. When a dental implant is influenced by the type of diabetes, its failure rate is higher in patients with type 1 diabetes than in patients with type 2 diabetes. The study included a number of 56 patients, who presented themselves for performing an implant. Of these, 7 patients did not perform an implant. Diabetes mellitus defines a chronic metabolic disorder, which may have multiple etiopathogenesis, characterized by changes in carbohydrate, lipid and protein metabolism. Stability of the implant in the bone, immediately after implantation is crucial for the success of the treatment; this immediate stability is called primary stability and is purely mechanical in nature.
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Casesnoves, Francisco. "Nonlinear Comparative Optimization for Biomaterials Wear in Artificial Implant Technology". Key Engineering Materials 800 (kwiecień 2019): 52–59. http://dx.doi.org/10.4028/www.scientific.net/kem.800.52.
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Today, artificial implants (AI) industry depends strongly on tribological constitution of the material (s) of the implant. Erosion, corrosion, tribocorrosion and biocorrosion are essential factors to determine both functionality and lifetime of the AIs. Histo-Biocompatibility is also an additional constraint, indispensable for implant manufacturing process. The prediction of durability, based on the computational and experimental study of constituents of AI material (s) are key factors to obtain objective data of any AI characteristics. This contribution deals with a computational comparative analysis of materials for hip implants using Archard’s model mainly. Selected hip implant material hardness are Co-Cr alloy and Titanium types. Method is carried out with specific material data, e.g., hardness or wear constants, nonlinear optimization and graphical subroutines. Results presented are both numerical and graphical. Particular interest is focused on application of the 3D Graphical Optimization method.
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Romanos, Georgios E., Gerard A. Fischer, Zaid T. Rahman i Rafael Delgado-Ruiz. "Spectrometric Analysis of the Wear from Metallic and Ceramic Dental Implants following Insertion: An In Vitro Study". Materials 15, nr 3 (4.02.2022): 1200. http://dx.doi.org/10.3390/ma15031200.
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Titanium wear is a growing area of interest within dental implantology. This study aimed to investigate titanium and zirconium wear from dental implants at the time of insertion using X-ray-fluorescence spectrometry (XRF) and an in vitro protocol utilizing artificial bovine bone plates. Five groups were analyzed using XRF-spectrometry: groups 1–4 (titanium implants) and group 5 (zirconia implants). The implants were inserted into two bone blocks held together by a vice. The blocks were separated, and the insertion sites were analyzed for titanium (Ti) and zirconium (Zr). Statistical descriptive analyses of Ti and Zr concentrations in the coronal, middle and apical bone interface were performed. A comparative analysis confirmed differences between the implant’s surface stability and Ti accumulation within the insertion sites of the bone block. There was a direct relationship between implant length and the quantity of titanium found on the bone block. The data generally indicates greater quantities of titanium in the coronal thirds of the implants, and less in the apical thirds. The titanium and zirconium found in the bone samples where the group 5 implants were inserted was not of statistical significance when compared to control osteotomies. The results of this study confirm wear from metallic, but not ceramic, dental implants at the time of insertion.
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Roman, Călin Rareş, i Lidia Adriana Sorcoi. "Preliminary Studies Regarding the Behaviour of New Titanium Implants". Materials Science Forum 672 (styczeń 2011): 233–36. http://dx.doi.org/10.4028/www.scientific.net/msf.672.233.
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This paper presents a study concerning a new titanium-based product reached by the specific techniques of powder metallurgy. The product was tested in vitro to corrosion in artificial saliva and in vivo by biological inocuity on sheep and rats for biocompatibility. The chemical composition of artificial saliva solutions used for general corrosion tests were: Fusayama solution; Carter solution; Ericsson solution; Hank solution; Ringer solution. The exposure length was 48, 720, 1440 and 2784 hours. On the sheep, six titanium implants of purity 99.89%, sintered with microporosities and nanoporosities at the surface were administered. Function of implant location, three cm incisions in the skin was made in the following regions: retroscapular for subcutaneous implants, in the tibial diaphysis for the subperiostal implant and in the Latimus Dorsi region for the intramuscular implant. Three different lots of Wistar breed rats were used; the sintered 3.5/1.5 cm titanium implants were placed subcutaneously and intermuscles. Parameters of descriptive statistics were used to assess inflammatory reaction.
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Ibrahim, Ahmad, Marius Heitzer, Anna Bock, Florian Peters, Stephan Christian Möhlhenrich, Frank Hölzle, Ali Modabber i Kristian Kniha. "Relationship between Implant Geometry and Primary Stability in Different Bony Defects and Variant Bone Densities: An In Vitro Study". Materials 13, nr 19 (30.09.2020): 4349. http://dx.doi.org/10.3390/ma13194349.
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Aim: This in vitro study aimed to evaluate the effects of implant designs on primary stability in different bone densities and bony defects. Methods: Five implant types (tapered-tissue-level, tissue-level, zirconia-tissue-level, bone-level, and BLX implants) were used in this assessment. The implants were inserted into four different artificial bone blocks representing varying bone-density groups: D1, D2, D3, and D4. Aside from the control group, three different types of defects were prepared. Using resonance frequency analysis and torque-in and -out values, the primary stability of each implant was evaluated. Results: With an increased defect size, all implant types presented reduced implant stability values measured by the implant stability quotient (ISQ) values. Loss of stability was the most pronounced around circular defects. Zirconia and bone-level implants showed the highest ISQ values, whereas tissue level titanium implants presented the lowest stability parameters. The implant insertion without any thread cut led to a small improvement in primary implant stability in all bone densities. Conclusions: Compared with implants with no peri-implant defects, the three-wall and one-wall defect usually did not provide significant loss of primary stability. A significant loss of stability should be expected when inserting implants into circular defects. Implants with a more aggressive thread distance could increase primary stability.
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Fortunato, P., M. Schettini i M. Gallucci. "Risk factors for urological prosthetic infection". Urologia Journal 64, nr 1 (luty 1997): 65–69. http://dx.doi.org/10.1177/039156039706400115.
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We reviewed our experience of 91 procedures for implant and revision of urological prostheses from 1989 to 1996. The aim of the study was to determine the risk factors for urological prostheses. The procedures consisted of 48 implants of artificial urinary sphincters AMS 800 (35 primary implants and 13 revisions) and 43 penile prostheses (40 primary implants and 3 revisions). Simultaneous penile reconstruction was performed in 5 cases. The mean follow-up was 2 years (range 1-6 years) for artificial urinary sphincter and 1.8 years (range 1-4) for penile prostheses. Infection occurred in 7 cases (4 urinary sphincter and 3 penile prostheses). The infection rate after primary uncomplicated implant of AMS 800 was 8.5% compared to 7.6% for revision procedures (p=n.s.). The infection rate after primary implant of penile prostheses was 5% compared to 33% for revision procedures. There was a similar significant difference between the penile prostheses implant group with reconstruction of the corpora (2 out 5 patients) and the primary uncomplicated implant group (p=0.001). The risk of infection is significantly greater when penile reconstruction is required and is associated with revision operations.
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Jeu, Samuel, Etienne Guillaud, Laurent Hauret, Jean-Christophe Coutant i Bruno Ella. "Assessment of the Correlation between the Implant Distance and Primary Stability by Resonance Frequency Analysis". Journal of Dental Surgery 2015 (10.06.2015): 1–7. http://dx.doi.org/10.1155/2015/568715.
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Objective. The aim of this study was to assess the influence of the interimplant distance on the implant primary stability (ISQ) by Resonance Frequency Analysis (RFA). Method. Forty-five implants were placed in the mandible of human cadavers and 108 in artificial bone substrates in the form of polyurethane foam blocks. Primary implant stability was successively measured first by RFA immediately after the placement of the first implant (A) and then after two other implants (B and C) proximal and distal to the first implant. The interimplant distances were defined from 1 to 6 mm and the three primary stability values measured were compared. Results. On the mandibles, no correlation was observed between the interimplant distances and primary stability. On the polyurethane foam block, the primary stability of implant A increased significantly (p<0.001) after the placement of implant B but remained constant after placement of implant C. Conclusion. Reducing the interimplant distance does not affect the primary stability on dry bone or artificial substrate.
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Cardoso, Mario J., i Michael K. Rosner. "Multilevel cervical arthroplasty with artificial disc replacement". Neurosurgical Focus 28, nr 5 (maj 2010): E19. http://dx.doi.org/10.3171/2010.1.focus1031.
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Object In this study, the authors review the technique for inserting the Prestige ST in a contiguous multilevel cervical disc arthroplasty in patients with radiculopathy and myelopathy. They describe the preoperative planning, surgical technique, and their experience with 10 patients receiving a contiguous Prestige ST implant. They present contiguous multilevel cervical arthroplasty as an alternative to multilevel arthrodesis. Methods After institutional board review approval was obtained, the authors performed a retrospective review of all contiguous multilevel cervical disc arthroplasties with the Prestige ST artificial disc between August 2007 and November 2009 at a single institution by a single surgeon. Clinical criteria included patients who had undergone a multilevel cervical disc arthroplasty performed for radiculopathy and myelopathy without the presence of a previous cervical fusion. Between August 2007 and November 2009, 119 patients underwent cervical arthroplasty. Of the 119 patients, 31 received a Hybrid construct (total disc resection [TDR]–anterior cervical decompression and fusion [ACDF] or TDR-ACDF-TDR) and 24 received a multilevel cervical arthroplasty. The multilevel cervical arthroplasty group consisted of 14 noncontiguous and 10 contiguous implants. This paper examines patients who received contiguous Prestige ST implants. Results Ten men with an average age of 45 years (range 25–61 years) were treated. Five patients presented with myelopathy, 3 presented with radiculopathy, and 2 presented with myeloradiculopathy. Twenty-two 6 × 16–mm Prestige ST TDRs were implanted. Six patients received 2-level Prestige ST implants. Five patients received TDRs at C5–6 and C6–7, and 1 patient received TDRs at C3–4 and C4–5. One patient received a TDR at C3–4, C5–6, and C6–7 where C4–5 was a congenital block vertebra. Three patients (2 with 3-level disease and 1 with 4-level disease) received contiguous Prestige ST implants as well as a Prevail ACDF as part of their constructs. The mean clinical and radiographic follow-up was 12 months. There has been no case of screw backout, implant dislodgment, progressive kyphosis, formation of heterotopic bone, evidence of pseudarthrosis at the Prevail levels, or development of symptomatic adjacent level disease. Conclusions Multilevel cervical arthroplasty with the Prestige ST is a safe and effective alternative to fusion for the management of cervical radiculopathy and myelopathy.
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Wang, X. G., Jie Mo Tian, Chuan Zeng Zhang, Zhi Ping Guo, Li Min Dong i Chang An Wang. "Study of Animal Bio-Ceramic Implants with 3D High Resolution CT". Key Engineering Materials 280-283 (luty 2007): 1629–30. http://dx.doi.org/10.4028/www.scientific.net/kem.280-283.1629.
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Animal implants experiments are obligatory when developing human artificial hard tissues, such as bio-ceramics. Optical microscope is often used to inspect implant slices but may destroy original status when slicing up. We tried 3D high resolution CT to nondestructively study biocompatibility and degradation of bio-ceramics implants. 3D CT provides 3D structure information. Typical pixel size of 3D high resolution CT is 50 microns. Generally, implants differs with tissues in density and structure, on basis of which we can identify details with CT slice. Experiments of bio-ceramic implanted into rabbit hip are also showed. Interaction could be identified at interface between implant and tissue.
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Fanali, Stefano, Margherita Tumedei, Pamela Pignatelli, Alessandra Lucchese, Francesco Inchingolo, Adriano Piattelli i Giovanna Iezzi. "Comparative In Vitro Evaluation of the Primary Stability in D3 Synthetic Bone of Two Different Shapes and Pitches of the Implant Threads". Applied Sciences 11, nr 12 (17.06.2021): 5612. http://dx.doi.org/10.3390/app11125612.
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Background: Implant primary stability can be affected by several factors related to implant macrogeometry, local anatomy, and surgical techniques. The aim of this research was to study primary stability on polyurethane foam sheets of wide-threaded implant design compared to narrow-threaded implants. Materials and methods: Two different implant designs were positioned on D3 density polyurethane blocks in a standardized environment: the wide-threaded implant and the narrow-threaded implant, for a total of 160 specimens. Moreover, for each group, two different sizes were considered: 3.8mm × 12mm and 4.8mm × 12 mm. The insertion torque (IT) values, the removal strength (RT), and the Periotest analyses were evaluated. Results: A significantly higher IT and RT was reported for wide-threaded implants and two-stage implants (p < 0.01), compared to the narrow-threaded implants. The diameters seemed to provide a significant effect on the primary stability for both implants’ geometry (p < 0.01). A higher mean of the one-stage implant was evident in the Periotest measurements (p < 0.01). Conclusions: Both of the implants showed sufficient stability in polyurethane artificial simulation, while the wide-threaded implant design showed a higher primary stability on alveolar cancellous synthetic bone in vitro. Additionally, the prosthetic joint connection seemed to have a determinant effect on Periotest analysis, and the one-stage implants seemed to provide a high stability of the fixture when positioned in the osteotomy, which could be important for the immediate loading protocol.
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Roumeliotis, George. "Bionic man: Principles and limits". Ηθική. Περιοδικό φιλοσοφίας, nr 13 (28.01.2021): 56. http://dx.doi.org/10.12681/ethiki.25985.
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The subject of this paper is the ethical considerations raised in the issue of “bionic man”, a man whose many organs have been replaced by artificial, and the principles and ethical limitations that are inherent in this process. Four basic bioethical principles are acknowledged in the international bibliography: a) the principle of beneficence; b) the principle of autonomy and informed consentof patients; c) the principle of justice; d) the principle of equality. Apart from this,some more issues should be taken into consideration in the discussion about theethics of artificial implants: the allocation of health care and economic resources, the patentability of implants, the use of implants in the human consciousness itself and the subsequent changes of implants in one’s personality, as well as the willingness of a patient to accept an implant under the prism of his/her belonging to a specific subculture, due to his/her impairment.
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Kumar, Priyadarshi Biplab, i Dayal R. Parhi. "Vibrational characterization of a human femur bone and its significance in the designing of artificial implants". World Journal of Engineering 14, nr 3 (12.06.2017): 222–26. http://dx.doi.org/10.1108/wje-07-2016-0033.
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Purpose Being an interdisciplinary research area, biomechanics has gained interest among researchers. Biomechanics deals with integration of mechanical phenomenon with the structural and functional aspects of biological systems. Biological systems being very much complex provide a very intricate platform for their analysis. In case of damages created by accidents or sport malfunctions, artificial implants are used for the replacement of bones. These implants may cause incompatibility with the human body, depending on their design and characterization. So, this research aims to analyze the vibrational characteristics of a human femur bone and to predict the safe ranges of frequencies of operation. Design/methodology/approach The current research is aimed at vibrational characterization of a human femur bone. The model of the femur bone is prepared using SOLIDWORKS software. The material properties of the femur are collected from the available literature and provided with the CAD model. The model is imported to the ANSYS software. Loading patterns as applied on the human body are also applied to the prepared model. Suitable boundary conditions are chosen for normal sitting and standing positions. The natural frequencies of the femur bone and other vibrational parameters are found out. Findings The first data obtained from the ANSYS software are the natural frequencies and mode shapes of vibration. Other data include the stress distributions, strain distributions, deformation patterns and potential zones of damage. The frequencies and mode shapes enable the safe ranges of human operation and the frequency range to be followed in the designing of implants. The stress distributions enable to know the potential zones of damage so that those areas can be given focus during strength considerations. Research limitations/implications The current investigations take into account only normal sitting and walking conditions. This work can be included under static loadings. This can also be extended toward dynamic loading conditions. In the dynamic loading, walking and running conditions can be taken into account. This work focuses on the safe designing of the artificial implants and their compatibility with the human body. This can also be extended toward role of dynamic forces in the damaged bone formation and the role of implant’s characteristics for healing of bones. Practical implications Bone damage and ligament fracture are common nowadays due to increasing number of accidents, which may be vehicular or sports. In case of any damage to the skeletal parts, some artificial implant is used to support the damaged part and to help in the process of healing. The designing of the implants must be compatible with the human body. The natural frequencies and mode shapes give an idea that the vibrational parameters of the implant material must fall in the same range as the actual bone. The stress distribution and potential zone damage emphasize on strength considerations. Originality/value The current method is a novel approach toward implant designing. Here an analysis of vibrational parameters of the human femur bone is performed. Those parameters include natural frequencies, mode shapes, principal normal stress distributions, principal shear stress distributions, maximum shear elastic strains and total deformation. These parameters reflect an idea about behavior of the femur bone under actual loading conditions. This analysis enables an implant designer to focus on material properties and strength considerations of the implants which are to be used in case of bone damage.
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Nakanishi, Yoshitaka, Tatsuki Takashima, Hidehiko Higaki, Ken Shimoto, Hiromasa Miura, Yukihide Iwamoto i Kenji Sunagawa. "WEAR RESISTANCE OF ARTIFICIAL ARTICULAR CARTILAGE FOR JOINT PROSTHESES(2D1 Artificial Organs & Implants II)". Proceedings of the Asian Pacific Conference on Biomechanics : emerging science and technology in biomechanics 2007.3 (2007): S157. http://dx.doi.org/10.1299/jsmeapbio.2007.3.s157.
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Lung, Hsuan, Jui-Ting Hsu, Aaron Yu-Jen Wu i Heng-Li Huang. "Biomechanical Effects of Diameters of Implant Body and Implant Platform in Bone Strain around an Immediately Loaded Dental Implant with Platform Switching Concept". Applied Sciences 9, nr 10 (16.05.2019): 1998. http://dx.doi.org/10.3390/app9101998.
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Dental implants designed with platform switching have been used clinically to reduce crestal bone resorption. The aim of this study was to determine the biomechanical effects of loading types, diameter of platform, and implant diameter in bone strain around immediately loaded implants with platform switching concept. Platform-switching features of dental implants with various diameters of implant body and implant platform (named as RP5.0, RP4.3, and NP3.5) were inserted into artificial bone blocks. The initial implant stability was confirmed using a Periotest device before the loading test. Rosette strain gauges were placed on the alveolar region around the implants, and peak values of the bone strain during a 190-N vertical load or 30-degree lateral load were measured by a data acquisition system. The Kruskal-Wallis test and post-hoc pairwise comparisons were performed as statistical analyses. The median Periotest values of the RP5.0, RP4.3, and NP3.5 implants ranged from −6.59 to −7.34. The RP5.0 implant always showed the lowest bone strain around the implant, regardless of whether a vertical or lateral load was applied. Relative to the RP4.3 and NP3.5 implants, the RP4.3 implant produced a higher bone strain (by approximately 8%) under a vertical load but a lower bone strain (by approximately 25%) under a lateral load. This study confirmed that using a wider implant could relieve the bone strain around an immediately loaded implant with platform switching concept especially under lateral loading.
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Goossens, Quentin, Leonard Cezar Pastrav, Michiel Mulier, Wim Desmet, Jos Vander Sloten i Kathleen Denis. "Two Different Methods to Measure the Stability of Acetabular Implants: A Comparison Using Artificial Acetabular Models". Sensors 20, nr 1 (1.01.2020): 254. http://dx.doi.org/10.3390/s20010254.
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The total number of total hip arthroplasties is increasing every year, and approximately 10% of these surgeries are revisions. New implant design and surgical techniques are evolving quickly and demand accurate preclinical evaluation. The initial stability of cementless implants is one of the main concerns of these preclinical evaluations. A broad range of initial stability test methods is currently used, which can be categorized into two main groups: Load-to-failure tests and relative micromotion measurements. Measuring relative micromotion between implant and bone is recognized as the golden standard for implant stability testing as this micromotion is directly linked to the long-term fixation of cementless implants. However, specific custom-made set-ups are required to measure this micromotion, with the result that numerous studies opt to perform more straightforward load-to-failure tests. A custom-made micromotion test set-up for artificial acetabular bone models was developed and used to compare load-to-failure (implant push-out test) with micromotion and to assess the influence of bone material properties and press-fit on the implant stability. The results showed a high degree of correlation between micromotion and load-to-failure stability metrics, which indicates that load-to-failure stability tests can be an appropriate estimator of the primary stability of acetabular implants. Nevertheless, micromotions still apply as the golden standard and are preferred when high accuracy is necessary. Higher bone density resulted in an increase in implant stability. An increase of press-fit from 0.7 mm to 1.2 mm did not significantly increase implant stability.
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Cohen, Omer, Ofer Moses, Talia Gurevich, Roni Kolerman, Alina Becker i Zeev Ormianer. "The Effect of Undersized Drilling on the Coronal Surface Roughness of Microthreaded Implants: An In Vitro Study". Applied Sciences 10, nr 15 (29.07.2020): 5231. http://dx.doi.org/10.3390/app10155231.
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This in-vitro study assessed the effect of an underdrilling implant placement protocol on the insertion torque, implant surface temperature and surface roughness (Sa) topography of the cervical microthreads of implants. Three groups of 25 implants (3.75 mm × 10 mm) were placed in osteotomies prepared in an artificial bone disc with final diameters of 3.65 mm according to the manufacturer’s instructions and in osteotomies prepared in accordance with an underdrilling protocol with final drill diameters of 3.2 and 2.8 mm (groups D3.65, D3.2, D2.8, respectively). Implants were inserted at a constant rate of 30 rpm. The surface temperature of the implants was measured with a thermal camera and temperature amplitude (Temp-Amp) was calculated by subtracting the room temperature from the measured implant surface temperature. Upon implant retrieval, coronal surface topography was assessed using a Nanofocus µsurf explorer and compared to a set of 25 new implants (control group). The differences between groups were compared using one-way ANOVA (p < 0.05). Significantly higher insertion torque, surface temperature values and significantly smaller average Sa values were measured in the implants inserted in undersized preparations. The highest temperature, insertion torque and Temp-Amp values and the largest decrease in Sa were measured in the D2.8 group. The lowest values were measured in the D3.65 group.
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Choi, Hoon, Jamie L. Baisden i Narayan Yoganandan. "A Comparative in vivo Study of Semi-constrained and Unconstrained Cervical Artificial Disc Prostheses". Military Medicine 184, Supplement_1 (1.03.2019): 637–43. http://dx.doi.org/10.1093/milmed/usy395.
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Abstract Purpose The objective of this study is to directly compare different types of cervical artificial disc implants using an in vivo model capable of simulating the axial load on a neck that is similar to the human neck. Methods Cervical arthroplasty was performed at C3-4 in 14 healthy female adult Alpine goats. The goats were divided into three groups. Group A received Bryan (unconstrained one-piece design); Group B received ProDisc-C (semi-constrained two-piece design); and Group C received Mobi-C (unconstrained three-piece design) artificial discs. The goats were monitored in a veterinary unit for 6 months with radiography at regular intervals. Results Each goat tolerated cervical arthroplasty well and had satisfactory placement of their implant per intra-operative radiography. Implants monitored in Group A demonstrated no migration. One out of five implants in Group B experienced anterior migration at 3 months. In Group C, anterior migration and disintegration occurred in all four implants, with migration occurring during the first postoperative week in three implants and after 5 weeks in the fourth. Conclusions Unconstrained multi-piece artificial cervical discs may be prone to anterior migration and extrusion out of the disc space. This outcome deserves attention in individuals with a hypermobile neck and/or an occupation involving the use of a head-supported mass, such as helmets.
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Geertman, M. E., A. P. Slagter, M. A. J. van Waas i W. Kalk. "Comminution of Food with Mandibular Implant-retained Overdentures". Journal of Dental Research 73, nr 12 (grudzień 1994): 1858–64. http://dx.doi.org/10.1177/00220345940730121101.
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When complete-denture wearers are treated with from four to six implants and mandibular implant-borne prostheses, masticatory performance improves. No significant improvement has been observed with two implants and implant-mucosa-borne overdentures, suggesting that the masticatory performance of edentulous subjects depends on the degree of support for their mandibular prostheses by implants or alveolar mucosa. To verify this hypothesis, we studied, in a randomized clinical trial, the comminution of an artificial test food during mastication. The trial involved the provision of a new maxillary denture and either a new conventional mandibular denture, a mandibular overdenture retained by two permucosal cylindric implants through a single bar-clip attachment, or a mandibular overdenture retained by a transmandibular implant through five clips on a triple-bar construction with cantilever extensions. In comparison with the subjects wearing mandibular implant-retained overdentures, the subjects with conventional complete dentures needed between 1.5 and 3.6 times more chewing strokes to achieve an equivalent reduction in particle size. No differences in masticatory performance and efficiency were found between the subjects who had received two permucosal cylindric implants and those who had received a transmandibular implant. The results suggest that the increased retention and stability of the mandibular denture, rather than the degree of support by implants or alveolar mucosa, determine the wearer's ability to comminute food during mastication.
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Meir, Haya, Alon Sebaoun, Perry Raz, Shifra Levartovsky, Adi Arieli, Raphel Pilo, Zafar Dor i Ilan Beitlitum. "Evaluation of Implant Stability and Trephination Depth for Implant Removal—An In Vitro Study". Materials 15, nr 12 (13.06.2022): 4200. http://dx.doi.org/10.3390/ma15124200.
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Malpositioned and broken implants are usually fully osseointegrated; hence, their removal, especially from the lower arch, can be very challenging. Implant removal techniques include reverse torque and trephination. Trephination is an invasive technique that can jeopardize vital structures, cause mandibular fatigue fractures, or lead to osteomyelitis. In this study, we aimed to assess the relationship between trephination depth and implant stability by recording implant stability quotient (ISQ) readings at varying trephination depths in vitro. Materials and methods: Forty-eight implants were inserted into dense synthetic polyurethane foam blocks as artificial bone. Primary implant stability was measured with a Penguin resonance frequency analysis (RFA) device. Implants of two designs with a diameter of 3.75 mm and a length of 13 or 8 mm were inserted. Twenty-four internal hexagon (IH) (Seven®) and twenty-four conical connection (CC) implants (C1®; MIS® Implants, Ltd., Misgav, Israel) were used. The primary implant stability was measured with the RFA device. Trephination was performed, and implant stability was recorded at depths of 0, 3, and 6 mm for the 8 mm implants and 0, 3, 6, 8, 10, and 11.5 mm for the 13 mm implants. Results: Linear regression revealed a significant relation between the trephination depth and the ISQ (F (1, 213) = 1113.192, p < 0.001, adjusted r2 = 0.839). The trephination depth significantly predicted the ISQ (β = −5.337, p < 0.001), and the ISQ decreased by −5.33 as the trephination depth increased by 1 mm. Conclusion: Implant stability reduction as measured using an RFA device during trephination may be a valuable guide to achieving safe reverse torque for implant removal. Further studies are needed to evaluate these data in clinical settings.
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Hodgins, Diana. "Artificial Means for Improving Human Motion". Applied Bionics and Biomechanics 1, nr 2 (2004): 131–32. http://dx.doi.org/10.1155/2004/742983.
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This paper gives a brief description of some of the key ongoing product developments in Europe for medical implants. A range of medical systems that are currently being developed under European-funded programmes are briefly described. The first is an implant that helps people with ‘dropped foot’ improve their walking. Further research on body-worn inertial measuring systems (IMUs) and microsystems will extend the capabilities to other lower-limb and upper-limb applications in the future. Other medical systems being developed with the use of microsystems and nanotechnology include a system to aid deaf and blind people.
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Shi, Yun, Ting Deng, Yu Peng, Zugan Qin, Murugan Ramalingam, Yang Pan, Cheng Chen, Feng Zhao, Lijia Cheng i Juan Liu. "Effect of Surface Modification of PEEK Artificial Phalanx by 3D Printing on its Biological Activity". Coatings 13, nr 2 (9.02.2023): 400. http://dx.doi.org/10.3390/coatings13020400.
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Objective: Polyetheretherketone (PEEK) is widely used as an orthopedic implant material owing to its good biocompatibility and mechanical strength; however, PEEK implants are biologically inert, resulting in suboptimal cellular responses after implantation. The aim of this study was to enhance the biological activity of PEEK through sulfonation treatment. Methods: In this study, distal phalangeal implants of PEEK were customized by fused deposition modeling (FDM) printing technology and soaked in concentrated sulfuric acid at different times to obtain sulfonated PEEK (SPEEK). The groups were divided into five groups according to the sulfonation time as follows: 0 min (control group), 1 min (group SPEEK1), 2 min (group SPEEK2), 4 min (group SPEEK4), and 8 min (group SPEEK8). Then the physicochemical characteristics of implants were determined by SEM, XRD, EDS, etc. The implants were co-cultured with stem cells from human exfoliated deciduous teeth (SHED), and then the cell proliferation, adhesion, alkaline phosphatase (ALP) activity, and alizarin red staining were performed to detect the biological activity, biocompatibility, and osteogenic activity of the SPEEK implants. Results: The sulfonation time range of 1 to 8 min could promote the formation of micropores on the surface of PEEK implants, while slightly affecting the composition and compression performance of the implants. Compared with the control group, the hydrophilicity of PEEK materials was not improved after sulfonation treatment. Tests for adhesion and proliferation of SHED indicated that SPEEK2 showed superior biocompatibility. Furthermore, ALP activity and semi-quantitative analysis of Alizarin red staining showed that the osteogenic activity of SPEEK2 phalanges exhibited significantly stronger osteogenic activity than the other groups. Conclusion: The method presented here provides a promising approach to improve the surface bioactivity of PEEK implants prepared by FDM, providing a shred of primary evidence to support the application of SPEEK in orthopedics.
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Shepherd, Duncan E. T., i Godfrey Azangwe. "Synthetic Versus Tissue-Engineered Implants for Joint Replacement". Applied Bionics and Biomechanics 4, nr 4 (2007): 179–85. http://dx.doi.org/10.1155/2007/675629.
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Human synovial joints are remarkable as they can last for a lifetime. However, they can be affected by disease that may lead to destruction of the joint surface. The most common treatment in the advanced stages of joint disease is artificial joint replacement, where the diseased synovial joint is replaced with an artificial implant made from synthetic materials, such as metals and polymers. A new technique for repairing diseased synovial joints is tissue engineering where cells are used to grow replacement tissue. This paper explores the relative merits of synthetic and tissue-engineered implants, using joint replacement as an example. Synthetic joint replacement is a well-established procedure with the advantages of early mobilisation, pain relief and high patient satisfaction. However, synthetic implants are not natural tissues; they can cause adverse reactions to the body and there could be a mismatch in mechanical properties compared to natural tissues. Tissue-engineered implants offer great potential and have major advantages over synthetic implants as they are natural tissue, which should ensure that they are totally biocompatible, have the correct mechanical properties and integrate well with the existing tissue. However, there are still many limitations to be addressed in tissue engineering such as scaling up for production, bioreactor design, appropriate regulation and the potential for disease to attack the new tissue-engineered implant.
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Alnaimat, F. A., H. A. Owida, A. Al Sharah, M. Alhaj i Mohammad Hassan. "Silicone and Pyrocarbon Artificial Finger Joints". Applied Bionics and Biomechanics 2021 (3.06.2021): 1–12. http://dx.doi.org/10.1155/2021/5534796.
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Artificial finger joint design has been developed through different stages through the past. PIP (proximal interphalangeal) and MCP (metacarpophalangeal) artificial finger joints have come to replace the amputation and arthrodesis options; although, these artificial joints are still facing challenges related to reactive tissues, reduced range of motion, and flexion and extension deficits. Swanson silicone artificial finger joints are still common due to the physician’s preferability of silicone with the dorsal approach during operation. Nevertheless, other artificial finger joints such as the pyrocarbon implant arthroplasty have also drawn the interests of practitioners. Artificial finger joint has been classified under three major categories which are constrained, unconstrained, and linked design. There are also challenges such as concerns of infections and articular cartilage necrosis associated with attempted retention of vascularity. In addition, one of the main challenges facing the silicone artificial finger joints is the fracture occurring at the distal stem with the hinge. The aim of this paper is to review the different artificial finger joints in one paper as there are few old review papers about them. Further studies need to be done to develop the design and materials of the pyrocarbon and silicone implants to increase the range of motion associated with them and the fatigue life of the silicone implants.
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Pilliar, R. M., J. E. Davies i D. C. Smith. "The Bone-Biomaterial Interface for Load-Bearing Implants". MRS Bulletin 16, nr 9 (wrzesień 1991): 55–61. http://dx.doi.org/10.1557/s0883769400056074.
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Bone-interfacing surgical implants used in orthopedics and dentistry must bear the forces of normal patient activity with minimal risk of mechanical failure of the implant. This requires using appropriate materials and designs for implant fabrication. Additionally, reliable long-term implant attachment to host bone must be assured so that effective force transfer between implant and bone occurs for the patient's lifetime without the implant loosening. With recent advances in implant designs and techniques for their placement, effective implant fixation to bone can last for years (decades) either directly or through an acceptable intermediate fibrous tissue layer at the bone-implant interface. With approximately 500,000 artificial hips implanted annually worldwide and the demand for other joint replacements approaching the same order of magnitude, as well as the recent major growth in the use of dental implants (300,300 projected for insertion in North America alone in 1991), the assurance of effective implant-to-bone fixation is extremely important.Studies of implant biocompatibility have resulted from concerns over the cumulative effects of foreign element release through implant corrosion and wear. Accumulation of this debris in tissues both local and remote to implant sites over the long term is a concern. Of equal importance, for load-bearing implants, are studies to determine the important factors for successful long-term implant fixation. Current trends in design and use of both dental and orthopedic implants reflect the trial-and-error approach that has characterized this field for decades.
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Unger, Felix. "Review article : Current status and use of artificial hearts and circulatory assist devices". Perfusion 1, nr 3 (lipiec 1986): 155–63. http://dx.doi.org/10.1177/026765918600100302.
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In a critical review, current status of artificial hearts and cardiac assist devices is discussed, based on 300000 clinical implantations of intra-aortic balloon pumps, 278 clinical cases of ventricular assist devices and 17 total artificial heart implants. It is justified to implant mechanical hearts as a bridge towards transplantation. Mechanical cardiac assistance has become almost a routine for teams dealing with cardiac transplantation.
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Finestone, Sandra. "Personal Experience with Breast Cancer". American Journal of Cosmetic Surgery 14, nr 4 (grudzień 1997): 403–4. http://dx.doi.org/10.1177/074880689701400405.
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One woman's personal experience with breast cancer, breast reconstruction, and breast implants. The article presents the author's conviction that there is no link between breast implants and the various ailments being reported. The author's concern that a woman facing breast cancer or a person requiring an artificial joint may find in the future fewer options available to help in the healing process because of misinformation and the way the media and FDA have handled the silicone gel implant issue.
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Senior, Kathryn. "Artificial implants: making the marriage work". Lancet 354, nr 9178 (sierpień 1999): 576. http://dx.doi.org/10.1016/s0140-6736(05)77930-7.
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Morgan, R. "Artificial implants and soft tissue sarcomas". Journal of Clinical Epidemiology 48, nr 4 (kwiecień 1995): 545–49. http://dx.doi.org/10.1016/0895-4356(94)00211-8.
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Fields, R. Douglas, Jean M. Le Beau, Frank M. Longo i Mark H. Ellisman. "Nerve regeneration through artificial tubular implants". Progress in Neurobiology 33, nr 2 (styczeń 1989): 87–134. http://dx.doi.org/10.1016/0301-0082(89)90036-1.
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Hall, C. William. "When Did Artificial Heart Implants Begin?" JAMA: The Journal of the American Medical Association 259, nr 11 (18.03.1988): 1650. http://dx.doi.org/10.1001/jama.1988.03720110020023.
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Hall, C. W. "When did artificial heart implants begin?" JAMA: The Journal of the American Medical Association 259, nr 11 (18.03.1988): 1650. http://dx.doi.org/10.1001/jama.259.11.1650.
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Mehta, Sahil, Gurmohan Singh, Harvinder Singh i Abhineet Saini. "A Review of Tribological Behavior of Different Bio-Implant Materials". ECS Transactions 107, nr 1 (24.04.2022): 5147–53. http://dx.doi.org/10.1149/10701.5147ecst.
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Biomedical implants are extensively gaining popularity owing to ever increasing health complications and growth in trauma numbers globally. Metallic implants are the most widely used bio-implants for various orthopedics and dentistry related problems owing to their superior mechanical strength when compared to ceramics and polymers. Furthermore, titanium alloys are the preferred choice these days, because of their proximate nature to human bone and light weight. However, few shortcomings make these artificial bio-implants capricious like short life span, wear rate, surface finish, etc. Tribological behavior and performance affect the life of the implant, and has to be improved for longer sustainability of the implants. Wear tests can help in predicting the life of the movable sliding joints in bio-implants. This paper includes a review about the properties of the bio material, wear tests results, and their wear mechanisms. Further, the limitation and scope of biomaterial implants from tribological aspects of various bio-materials are reviewed.
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Romanos, Georgios E., Daniel J. Bastardi, Rachel Moore, Apoorv Kakar, Yaro Herin i Rafael A. Delgado-Ruiz. "In Vitro Effect of Drilling Speed on the Primary Stability of Narrow Diameter Implants with Varying Thread Designs Placed in Different Qualities of Simulated Bone". Materials 12, nr 8 (25.04.2019): 1350. http://dx.doi.org/10.3390/ma12081350.
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It is hypothesized that there is no statistically significant impact of drilling speed (DS) on the primary stability (PS) of narrow-diameter implants (NDIs) with varying thread designs placed in dense and soft simulated bone. The aim of this in vitro study was to evaluate the impact of DS on the PS of NDIs with varying thread designs placed in dense and soft simulated bone. Two hundred and forty osteotomies for placement of various implant macro-designs were divided into three groups (80 implants per group): Group A (NobelActive, 3.0/11.5 mm); Group B (Astra OsseoSpeed-EV, 3.0/11 mm); and Group C (Eztetic-Zimmer, 3.1/11.5 mm) implants. These implants were placed in artificial dense and soft simulated bone using DSs of 800 and 2000 revolutions per minute (RPM). Resonance frequency analysis (RFA) and implant stability quotient (ISQ) were assessed. Group comparisons were performed using the one-way analysis of variance with Tukey’s post hoc tests. Level of significance was set at P < 0.05. In groups A and B, there was no difference in the ISQ for NDIs inserted in dense bone at 800 and 2000 RPM. In Group C, ISQ was significantly higher for NDIs placed in dense bone at 800 PRM compared to 2000 RPM (P < 0.05). In Group A, ISQ values were significantly higher for NDIs inserted in soft bone at 2000 RPM as compared to those inserted at 800 RPM (P < 0.05). For NDIs, a lower drilling speed in dense artificial simulated bone and a higher drilling speed in soft artificial simulated bone is associated with high primary stability.
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Romanos, Georgios E., Rafael Arcesio Delgado-Ruiz i Ana I. Nicolas-Silvente. "Volumetric Changes in Morse Taper Connections After Implant Placement in Dense Bone. In-Vitro Study". Materials 13, nr 10 (16.05.2020): 2306. http://dx.doi.org/10.3390/ma13102306.
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The stability of the implant–abutment interface is crucial for the maintenance of the implant index integrity. Several factors are capable of inducing deformation in implant–abutment connection, such as the actual insertion of the implant into the bone. This study aimed to evaluate the deformations produced in the connection after the insertion of the implant. Ten implants with two different implant carriers (Type A: carrier attached to platform and Type B: carrier attached inside the index-connection) were placed in artificial Type II bone, and volumetric changes were evaluated for different connection features with a 3D digital microscope. ANOVA (analysis of variance), Wilcoxon, and Tukey HSD post-test were used for statistical comparisons. Type A implants presented deformation at the platform level (inner slot angles and slot width), but no volumetric changes were observed inside the connection. Type B implants presented deformation in three parameters inside the connection (outer channel length, coronal step width, and coronal step length). Within the limitations of this study, we can conclude that more deformation is expected at the internal connection when the implant carrier engages this area. The engagement area should be as far away as possible from the index connection.
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Batista, N. A., A. A. Rodrigues, V. P. Bavaresco, J. R. L. Mariolani i W. D. Belangero. "Polyvinyl Alcohol Hydrogel Irradiated and Acetalized for Osteochondral Defect Repair: Mechanical, Chemical, and Histological Evaluation after Implantation in Rat Knees". International Journal of Biomaterials 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/582685.
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Polyvinyl Alcohol (PVA) hydrogel plugs were implanted in artificial osteochondral defects on the trochlear groove of rat knees. After 0, 3, 6, 12, and 24 weeks of followup, samples containing the implants were mechanically evaluated by creep indentation test, chemically, and histologically by optical microscopy. The mechanical test pointed towards an increase of the implant creep modulus and the chemical analysis exhibited an increasing concentration of calcium and phosphorus within the implants over time. Optical microscopy showed no foreign body reaction and revealed formation, differentiation, and maintenance of new tissue at the defect/implant interface. The absence of implant wear indicated that the natural articular lubrication process was not disturbed by the implant. The performance of the irradiated and acetalized PVA was considered satisfactory for the proposed application.
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Ylinen, P., R. M. Tulamo, M. Kellomäki, P. Türmälä, P. Rokkanen i T. Palmgren. "Lumbar intervertebral disc replacement using bioabsorbable self-reinforced poly-L-lactide full-threaded screws, or cylindrical implants of polylactide polymers, bioactive glass and Polyactive™". Veterinary and Comparative Orthopaedics and Traumatology 16, nr 03 (lipiec 2003): 138–44. http://dx.doi.org/10.1055/s-0038-1632777.
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SummaryIntervertebral disc surgery leads to changes in the segmental anatomy and mobility, and subsequently to degenerative changes in the lumbar spine. Artificial intervertebral disc implants sufficient to replace the human lumbar intervertebral disc have been developed and the requirements for these defined. This is to our knowledge the first study on bioabsorbable intervertebral disc replacement implants. SR-PLLA screws, previously used in orthopaedic internal fixations, and cylindrical implants, specifially developed for this experimental preliminary study, were used to replace lumbar intervertebral discs of growing pigs. After a 15-week follow-up period, the radiological and histological changes in the intervertebral spaces were analyzed. The cylindrical implants were able to prevent narrowing of discectomied spaces, and tissue regeneration in the intervertebral space was induced and occured simultaneously with degradation of the implant.
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Satpathy, Megha, Hai Pham i Shreya Shah. "Performance of Dental Cements Used for Bonding Zirconia Crowns with Titanium Implants Embedded in an Innovative Bi-Layered Artificial Bone". Ceramics 6, nr 1 (2.03.2023): 651–63. http://dx.doi.org/10.3390/ceramics6010039.
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This study aimed to investigate four dental adhesive cements and develop a new method for constructing a bi-layered bone holder for implant testing. HahnTM Tapered Titanium Implants (Glidewell Laboratories) were embedded in mono- and bi-layered holders, and the implant components were assembled. First molar zirconia crowns and crowns for the tensile bond strength test were milled and sintered. Three self-adhesive resin cements (SARC) and one resin-modified glass ionomer (RMGI, Glidewell Laboratories) cement were used to cement the crowns on the abutment. Tensile bond strength, compressive load, and oblique load tests were performed on the implants. The Glidewell Experimental SARC (GES, Glidewell Laboratories) and RMGI cements had the highest tensile bond strength after thermocycling. The implant assemblies with these two cements had the highest mean compressive strength after thermocycling. Under oblique load, the implants with Denali (Glidewell Laboratories) and GES had the highest strength before thermocycling. However, after thermocycling, Dencem (Dentex) and RMGI had the highest strength under an oblique load. The GES cement and RMGI cement had a better overall performance with zirconia crowns and titanium abutments. In addition, a novel technique for constructing an artificial, bi-layered bone holder was successfully developed to mimic the natural structure of the jawbone.
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Lee, Ui-Lyong, Seokhwan Yun, Hua-Lian Cao, Geunseon Ahn, Jin-Hyung Shim, Su-Heon Woo i Pill-Hoon Choung. "Bioprinting on 3D Printed Titanium Scaffolds for Periodontal Ligament Regeneration". Cells 10, nr 6 (28.05.2021): 1337. http://dx.doi.org/10.3390/cells10061337.
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The three-dimensional (3D) cell-printing technique has been identified as a new biofabrication platform because of its ability to locate living cells in pre-defined spatial locations with scaffolds and various growth factors. Osseointegrated dental implants have been regarded as very reliable and have long-term reliability. However, host defense mechanisms against infections and micro-movements have been known to be impaired around a dental implant because of the lack of a periodontal ligament. In this study, we fabricated a hybrid artificial organ with a periodontal ligament on the surface of titanium using 3D printing technology. CEMP-1, a known cementogenic factor, was enhanced in vitro. In animal experiments, when the hybrid artificial organ was transplanted to the calvarial defect model, it was observed that the amount of connective tissue increased. 3D-printed hybrid artificial organs can be used with dental implants, establishing physiological tooth functions, including the ability to react to mechanical stimuli and the ability to resist infections.
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Sifi, M., Fethi Benkhenafou, D. Bennacer, M. Benaissa i B. Serier. "Mechanical Behavior of the Spacing between Two Dental Implants". Advanced Materials Research 811 (wrzesień 2013): 297–303. http://dx.doi.org/10.4028/www.scientific.net/amr.811.297.
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Replace lost teeth by artificial prosthetic has been a preoccupation since the dawn of human time. The aim of our work is to study mechanical behavior of the interaction distance between two dental implants, in order to serve as support for a crown, a bridge element or an attachment of the prosthesis.Our purpose is to make a comparative study of five models that is different only by the interaction distance between 0.5 mm and 2 mm spacing two implants, to clarify the mechanical behavior of this interaction distance. The used materials are the biomaterials which are intended to be in contact with biological systems. Modeling of dental implant and the various components is done using Solidworks.We studied the static mechanical behavior of the implant using numerical methods.
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Tumedei, Margherita, Morena Petrini, Davide Pietropaoli, Alessandro Cipollina, Castrenze La Torre, Maria Stella Di Carmine, Adriano Piattelli i Giovanna Iezzi. "The Influence of the Implant Macrogeometry on Insertion Torque, Removal Torque, and Periotest Implant Primary Stability: A Mechanical Simulation on High-Density Artificial Bone". Symmetry 13, nr 5 (30.04.2021): 776. http://dx.doi.org/10.3390/sym13050776.
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Background: The primary stability is a determinant clinical condition for the success of different dental implants macro-design in different bone density using a validated and repeatable in vitro technique employing solid rigid polyurethane blocks. Materials and Methods: Five implants 3.8 × 13 mm2 for each macro-design (i.e., IK—tapered; IC—cylindric; and IA—active blade shape) were positioned into 20- and 30- pounds per cubic foot (PCF) polyurethane blocks. Bucco-lingual (BL) and mesial-distal (MD) implant stability quotient score (ISQ) was assessed by resonance frequency analysis while, insertion/removal torques were evaluated by dynamometric ratchet. Results: IC implants shown better primary stability in terms of ISQ compared to IA and IK in lower density block (20 PCF), while IK was superior to IA in higher density (30 PCF). IC shown higher removal torque in 30-PCF compared to IA and IC. Conclusions: The study effectiveness on polyurethane artificial bone with isotropic symmetry structure showed that the implants macro-design might represent a key factor on primary stability, in particular on low-density alveolar bone. Clinicians should consider patients features and implant geometry during low-density jaws rehabilitation. Further investigations are needed to generalize these findings.
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DiCesare, Jasmine A. T., Alexander M. Tucker, Irene Say, Kunal Patel, Todd H. Lanman, Frank J. Coufal, Justin Millard, Jeffrey E. Deckey, Siddharth Shetgeri i Duncan Q. McBride. "Mechanical failure of the Mobi-C implant for artificial cervical disc replacement: report of 4 cases". Journal of Neurosurgery: Spine 33, nr 6 (grudzień 2020): 727–33. http://dx.doi.org/10.3171/2020.5.spine19442.
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Cervical spondylosis is one of the most commonly treated conditions in neurosurgery. Increasingly, cervical disc replacement (CDR) has become an alternative to traditional arthrodesis, particularly when treating younger patients. Thus, surgeons continue to gain a greater understanding of short- and long-term complications of arthroplasty. Here, the authors present a series of 4 patients initially treated with Mobi-C artificial disc implants who developed postoperative neck pain. Dynamic imaging revealed segmental kyphosis at the level of the implant. All implants were locked in the flexion position, and all patients required reoperation. This is the first reported case series of symptomatic segmental kyphosis after CDR.
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Tsuchiya, Shuhei. "Functional analysis of chondroitin 4 sulfate constituting osseointegration". Impact 2019, nr 8 (26.11.2019): 18–20. http://dx.doi.org/10.21820/23987073.2019.8.18.
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Osseointegration can be defined as a direct connection, both structural and functional, between living bone and the surface of an artificial implant. Indeed, the word comes from the Greek term for 'bone' and 'to make whole'. In dentistry, once dental implants are placed, the body will react with osseointegration, enabling the implants to become a permanent part of the jaw. There are many benefits to this type of implant, compared with traditional tooth replacement options, not least that dental implants mimic the strength and functionality of a natural tooth. Dr Shuhei Tsuchiya is a researcher based in the Division of Oral and Maxillofacial Surgery at Nagoya University, Japan, who is interested in a range of areas, including regenerative medicine and the extracellular matrix. One of his key preoccupations, though, is shedding light on osseointegration. He and his team are working to unravel the mysteries of the mechanism.
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Kohal, Ralf-Joachim, Anja Trinkner, Felix Burkhardt, Sebastian Berthold Maximilian Patzelt, Kirstin Vach, Monika Kušter, Anže Abram, Andraž Kocjan i Julian Nold. "Long-Term Stability of Hydrothermally Aged and/or Dynamically Loaded One-Piece Diameter Reduced Zirconia Oral Implants". Journal of Functional Biomaterials 14, nr 3 (24.02.2023): 123. http://dx.doi.org/10.3390/jfb14030123.
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The aim of this in vitro study was to evaluate the long-term stability of one-piece diameter reduced zirconia oral implants under the influence of loading and artificial aging in a chewing simulator as well as the fracture load in a static loading test. Thirty-two one-piece zirconia implants with a diameter of 3.6 mm were embedded according to the ISO 14801:2016 standard. The implants were divided into four groups of eight implants. The implants of group DLHT were dynamically loaded (DL) in a chewing simulator for 107 cycles with a load of 98 N and simultaneously hydrothermally aged (HT) using a hot water bath at 85 °C. Group DL was only subjected to dynamic loading and group HT was exclusively subjected to hydrothermal aging. Group 0 acted as a control group: no dynamical loading, no hydrothermal ageing. After exposure to the chewing simulator, the implants were statically loaded to fracture in a universal testing machine. To evaluate group differences in the fracture load and bending moments, a one-way ANOVA with Bonferroni correction for multiple testing was performed. The level of significance was set to p < 0.05. In the static loading test, group DLHT showed a mean fracture load of 511 N, group DL of 569 N, group HT of 588 N and control group 0 of 516 N. The average bending moments had the following values: DLHT: 283.5 Ncm; DL: 313.7 Ncm; HT: 324.4 Ncm; 0: 284.5 Ncm. No significant differences could be found between the groups. Hydrothermal aging and/or dynamic loading had no significant effect on the stability of the one-piece diameter reduced zirconia implants (p > 0.05). Within the limits of this investigation, it can be concluded that dynamic loading, hydrothermal aging and the combination of loading and aging did not negatively influence the fracture load of the implant system. The artificial chewing results and the fracture load values indicate that the investigated implant system seems to be able to resist physiological chewing forces also over a long service period.
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Sultan, Haseeb, Muhammad Owais, Jiho Choi, Tahir Mahmood, Adnan Haider, Nadeem Ullah i Kang Ryoung Park. "Artificial Intelligence-Based Solution in Personalized Computer-Aided Arthroscopy of Shoulder Prostheses". Journal of Personalized Medicine 12, nr 1 (14.01.2022): 109. http://dx.doi.org/10.3390/jpm12010109.
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Background: Early recognition of prostheses before reoperation can reduce perioperative morbidity and mortality. Because of the intricacy of the shoulder biomechanics, accurate classification of implant models before surgery is fundamental for planning the correct medical procedure and setting apparatus for personalized medicine. Expert surgeons usually use X-ray images of prostheses to set the patient-specific apparatus. However, this subjective method is time-consuming and prone to errors. Method: As an alternative, artificial intelligence has played a vital role in orthopedic surgery and clinical decision-making for accurate prosthesis placement. In this study, three different deep learning-based frameworks are proposed to identify different types of shoulder implants in X-ray scans. We mainly propose an efficient ensemble network called the Inception Mobile Fully-Connected Convolutional Network (IMFC-Net), which is comprised of our two designed convolutional neural networks and a classifier. To evaluate the performance of the IMFC-Net and state-of-the-art models, experiments were performed with a public data set of 597 de-identified patients (597 shoulder implants). Moreover, to demonstrate the generalizability of IMFC-Net, experiments were performed with two augmentation techniques and without augmentation, in which our model ranked first, with a considerable difference from the comparison models. A gradient-weighted class activation map technique was also used to find distinct implant characteristics needed for IMFC-Net classification decisions. Results: The results confirmed that the proposed IMFC-Net model yielded an average accuracy of 89.09%, a precision rate of 89.54%, a recall rate of 86.57%, and an F1.score of 87.94%, which were higher than those of the comparison models. Conclusion: The proposed model is efficient and can minimize the revision complexities of implants.