946 resultados para Prostheses and implants
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Halitosis is the unpleasant odor of exhaust air through the mouth and lungs. There are over 50 causes, and approximately 90% of cases, is of oral origin. May have physiological origin (stress, breath of morning, fasting, and inappropriate diets), local reasons (bad oral hygiene, bacterial plaque retained on the tongue and/or tonsils, lower production of saliva, gum disease) or systemic reasons (diabetes, kidney or liver problems, constipation, etc.). In the Third Age, this problem tends to increase significantly. Thus, the aim of this study was to detect the presence of halitosis in the geriatric group attended in the dental clinic of UNIRP, identifying their incidence and principal causes. The sample consisted of 48 volunteer patients aged 60 years or older and included more than 90% of patients treated in this age group. It was performed a anamnesis and physical examination. The intra-oral halitosis was detected using a breath meter (halimeter). In the group studied, approximately 54.16% had halitosis, 84.61% of these were users of the prosthesis. The tongue coating was present in 80.76% of individuals with halitosis. After brushing the tongue, 88.46% of patients with halitosis have had the initial index oral malodor decreased. Based on the results of this study it was concluded that factors as dental prostheses and tongue coating are critical factors in causing halitosis.
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Eye loss results on facial asymmetry compromising its aesthetics. Ocular prostheses are important to re-establish aesthetics; protect the anophthalmic cavity; recover function such as the redirection of lachrymatory liquid; and reintegrate the patient to society. The aim of this study was to describe a case report, demonstrating clinical and laboratorial procedures for confection of ocular prostheses and highlighting their advantages. A female patient was afflicted by toxoplasmosis, which led to the loss of her eye. An eye visceration was performed. The patient reported no previous use of ocular prosthesis. A PMMA ocular prosthesis was manufactured restoring patient’s aesthetic and facial contour. The patient was satisfied with the treatment. Therefore the present study has shown that PMMA ocular prosthesis is able to restore facial aesthetics and can be a safe and satisfactory alternative for patients that have lost their eyes due to toxoplasmosis.
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With the search for treatments faster and aesthetic improvement of materials and surgical techniques, immediate implants have become a clinical reality increasingly practiced. Thus, based on literature the specific purpose of this study was to address critically the concepts of immediate implants, discussing issues related to dental extraction, milling technique, care of the periodontal tissues support and protection, prosthetic replacement, benefits, indications and contraindications. To this end, from Pubmed electronic crawler Medline, 54 articles published between 1990 and 2009, over 4 items classics, all in English were selected. The Studies have shown success rates for this technique Conventional techniques like two-stage surgery, many different techniques and planning are present among these techniques, and implants more immediate subject to failures.
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The knee joint is a key structure of the human locomotor system. The knowledge of how each single anatomical structure of the knee contributes to determine the physiological function of the knee, is of fundamental importance for the development of new prostheses and novel clinical, surgical, and rehabilitative procedures. In this context, a modelling approach is necessary to estimate the biomechanic function of each anatomical structure during daily living activities. The main aim of this study was to obtain a subject-specific model of the knee joint of a selected healthy subject. In particular, 3D models of the cruciate ligaments and of the tibio-femoral articular contact were proposed and developed using accurate bony geometries and kinematics reliably recorded by means of nuclear magnetic resonance and 3D video-fluoroscopy from the selected subject. Regarding the model of the cruciate ligaments, each ligament was modelled with 25 linear-elastic elements paying particular attention to the anatomical twisting of the fibres. The devised model was as subject-specific as possible. The geometrical parameters were directly estimated from the experimental measurements, whereas the only mechanical parameter of the model, the elastic modulus, had to be considered from the literature because of the invasiveness of the needed measurements. Thus, the developed model was employed for simulations of stability tests and during living activities. Physiologically meaningful results were always obtained. Nevertheless, the lack of subject-specific mechanical characterization induced to design and partially develop a novel experimental method to characterize the mechanics of the human cruciate ligaments in living healthy subjects. Moreover, using the same subject-specific data, the tibio-femoral articular interaction was modelled investigating the location of the contact point during the execution of daily motor tasks and the contact area at the full extension with and without the whole body weight of the subject. Two different approaches were implemented and their efficiency was evaluated. Thus, pros and cons of each approach were discussed in order to suggest future improvements of this methodologies. The final results of this study will contribute to produce useful methodologies for the investigation of the in-vivo function and pathology of the knee joint during the execution of daily living activities. Thus, the developed methodologies will be useful tools for the development of new prostheses, tools and procedures both in research field and in diagnostic, surgical and rehabilitative fields.
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[EN]The number of eggs obtained in natural spawning (25.60 million) is higher than those obtained by injections (12.9 million) and implants (10.5 million). The number of eggs per female was 12.80 million, in natural spawning, and 4.30 and 3.51 million, in induced with injections and implants, respectively. In number of eggs per spawn, significant differences was observed, between natural spawns (1.11 million), and induced spawning’s (0.44 and 0.21 millions, injected and implants respectively). Significant differences was also found, in number of eggs per Kg female/spawn, between natural spawning’s (56,700 eggs), injection induced (37,200 eggs) and implants (25,200 eggs).
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L'attività di ricerca descritta in questa tesi fornisce linee guida per la progettazione di arti protesici inferiori, con particolare riferimento alla progettazione di protesi a basso costo. La necessità di efficienti protesi a basso costo risulta infatti sentita nei Paesi in via di sviluppo ma anche dalle fasce meno abbienti dei paesi occidentali. Al fine di comprendere le strategie adottate dall'apparato locomotorio per muoversi con le protesi sono analizzati il cammino fisiologico, le protesi presenti sul mercato ed infine le modalità con cui le loro prestazioni sono valutate. Con il presente lavoro, dopo aver osservato la presenza di una scarsa strutturazione della metodologia di progettazione che riguarda specialmente il settore del basso costo, si propone una metodologia il più possibile oggettiva e ripetibile tesa ad individuare quali sono gli aspetti essenziali di una protesi per garantire al paziente una buona qualità di vita. Solo questi aspetti dovranno essere selezionati al fine di ottenere la massima semplificazione della protesi e ridurre il più possibile i costi. Per la simulazione delle attività di locomozione, in particolare del cammino, è stato elaborato un apposito modello spaziale del cammino. Il modello proposto ha 7 membri rigidi (corrispondenti a piedi, tibie, femori e bacino) e 24 gradi di libertà. Le articolazioni e l'appoggio dei piedi al suolo sono modellati con giunti sferici. La pianta del piede consente tre possibili punti di appoggio. I criteri di realizzazione delle simulazioni possono comprendere aspetti energetici, cinematici e dinamici considerati come obiettivo dall'apparato locomotorio. In questa tesi vengono trattati in particolare gli aspetti cinematici ed è mostrata un'applicazione della procedura nella quale vengono dapprima identificati i riferimenti fisiologici del cammino e quindi simulato il cammino in presenza di una menomazione al ginocchio (eliminazione della flessione in fase di appoggio). Viene quindi lasciato a sviluppi futuri il completamento della procedura e la sua implementazione in un codice di calcolo.
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The relevance of human joint models has been shown in the literature. They can help in diagnosis, in prostheses and ortheses design and in predicting the joints’ behavior. Recently a sequential approach for the modeling of the human diarthrodial joints composed of three steps has been proposed. At each step the role of some anatomical structures is considered. Starting from a limited number of structures, the model gets more and more sophisticated until all the components, both passive (articular surfaces, ligaments and tendons) and active (muscles), are incorporated in the final model. According to this procedure, the behavior of the human ankle during passive motion (no loads applied) has been previously modeled by a one degree of freedom 5-5 fully parallel mechanism. Starting from this model, the kinetostatic model of the human ankle joint that replicates its behavior when external loads are applied is developed. The anatomical and mechanical characteristics and the role of the passive structures are considered; a multifiber model is developed and an optimization criteria based on experimental data is proposed. Finally an application of the developed model to an amputated ankle is presented, together with the results obtained from the optimization of the geometrical and mechanical Parameters. Although some improvements can be achieved, the model is satisfactorily able to replicate the behavior of the human ankle subject to the anterior drawer and the inversion clinical tests applied in the neutral position.
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Questa tesi valuta l’efficacia della tecnica delle griglie in titanio con osso particolato nella ricostruzione dei difetti alveolari tridimensionali ai fini della riabilitazione dentale implanto-protesica. Il primo studio ha considerato la metodica in termini di complicanze post-operatorie e di risultati implanto-protesici. Sono stati considerati 24 pazienti con difetti tridimensionali trattati con l’applicazione di 34 griglie di titanio e osso particolato e riabilitati protesicamente dopo circa 8-9 mesi. 4 su 34 griglie sono state rimosse prima dell’inserimento implantare (11.76% di fallimento totale); 20 su 34 griglie si sono esposte per deiscenza dei tessuti molli (58.82% di complicanze): 4 (11.77%) prima e 16 (47.05%) dopo le prime 4-6 settimane dall’intervento; in nessun caso il piano di trattamento implanto-protesico ha subito variazioni. Dopo un follow-up medio di 20 (3-48) mesi dal carico protesico, nessuno degli 88 impianti ha perso la propria osteo-integrazione (100% di sopravvivenza implantare), con un valore complessivo di successo implantare di 82.9%. Il secondo studio ha calcolato in termini volumetrici la ricostruzione ossea ottenuta con griglie e la sua corre-lazione con l’estensione dell’esposizione e la tempistica del suo verificarsi. Sono stati valutati 12 pazienti con 15 difetti alveolari. Per ciascun sito sono state studiate le immagini TC con un software dedicato per misurare i volumi in tre dimensioni: il volume di osso non formatosi rispetto a quanto pianificato, lacking bone volume (LBV), è stato calcolato sottraendo il volume di osso ricostruito, reconstructed bone volume (RBV) in fase di ri-entro chirurgico dal volume di osso pianificato pre-operativamente, planned bone volume (PBV). LBV è risultato direttamente proporzionale all’area di esposizione della griglia, con un valore del 16.3% di LBV per ogni cm2 di griglia esposta. Si sono evidenziate, inoltre, correlazioni positive tra LBV , la tempistica precoce di esposizione e il valore di PBV.
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Surgical navigation systems visualize the positions and orientations of surgical instruments and implants as graphical overlays onto a medical image of the operated anatomy on a computer monitor. The orthopaedic surgical navigation systems could be categorized according to the image modalities that are used for the visualization of surgical action. In the so-called CT-based systems or 'surgeon-defined anatomy' based systems, where a 3D volume or surface representation of the operated anatomy could be constructed from the preoperatively acquired tomographic data or through intraoperatively digitized anatomy landmarks, a photorealistic rendering of the surgical action has been identified to greatly improve usability of these navigation systems. However, this may not hold true when the virtual representation of surgical instruments and implants is superimposed onto 2D projection images in a fluoroscopy-based navigation system due to the so-called image occlusion problem. Image occlusion occurs when the field of view of the fluoroscopic image is occupied by the virtual representation of surgical implants or instruments. In these situations, the surgeon may miss part of the image details, even if transparency and/or wire-frame rendering is used. In this paper, we propose to use non-photorealistic rendering to overcome this difficulty. Laboratory testing results on foamed plastic bones during various computer-assisted fluoroscopybased surgical procedures including total hip arthroplasty and long bone fracture reduction and osteosynthesis are shown.
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This paper reviews the methods, benefits and challenges associated with the adoption and translation of computational fluid dynamics (CFD) modelling within cardiovascular medicine. CFD, a specialist area of mathematics and a branch of fluid mechanics, is used routinely in a diverse range of safety-critical engineering systems, which increasingly is being applied to the cardiovascular system. By facilitating rapid, economical, low-risk prototyping, CFD modelling has already revolutionised research and development of devices such as stents, valve prostheses, and ventricular assist devices. Combined with cardiovascular imaging, CFD simulation enables detailed characterisation of complex physiological pressure and flow fields and the computation of metrics which cannot be directly measured, for example, wall shear stress. CFD models are now being translated into clinical tools for physicians to use across the spectrum of coronary, valvular, congenital, myocardial and peripheral vascular diseases. CFD modelling is apposite for minimally-invasive patient assessment. Patient-specific (incorporating data unique to the individual) and multi-scale (combining models of different length- and time-scales) modelling enables individualised risk prediction and virtual treatment planning. This represents a significant departure from traditional dependence upon registry-based, population-averaged data. Model integration is progressively moving towards 'digital patient' or 'virtual physiological human' representations. When combined with population-scale numerical models, these models have the potential to reduce the cost, time and risk associated with clinical trials. The adoption of CFD modelling signals a new era in cardiovascular medicine. While potentially highly beneficial, a number of academic and commercial groups are addressing the associated methodological, regulatory, education- and service-related challenges.
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The possibility of designing and manufacturing biomedical microdevices with multiple length-scale geometries can help to promote special interactions both with their environment and with surrounding biological systems. These interactions aim to enhance biocompatibility and overall performance by using biomimetic approaches. In this paper, we present a design and manufacturing procedure for obtaining multi-scale biomedical microsystems based on the combination of two additive manufacturing processes: a conventional laser writer to manufacture the overall device structure, and a direct-laser writer based on two-photon polymerization to yield finer details. The process excels for its versatility, accuracy and manufacturing speed and allows for the manufacture of microsystems and implants with overall sizes up to several millimeters and with details down to sub-micrometric structures. As an application example we have focused on manufacturing a biomedical microsystem to analyze the impact of microtextured surfaces on cell motility. This process yielded a relevant increase in precision and manufacturing speed when compared with more conventional rapid prototyping procedures.
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Conclusion. The new Provox(R) NID (TM) non- indwelling voice prosthesis investigated in this study provides a good option for laryngectomized patients using non- indwelling voice prostheses and can potentially improve safety and increase patients' satisfaction with their voice and speech. Objective. To investigate the feasibility of and patient satisfaction with the Provox NID non- indwelling voice prosthesis. Material and methods. Pre- and post- study questionnaires were used to evaluate the patients' former voice prosthesis and the Provox NID voice prosthesis. In addition, measurements of pull- out force, maximum phonation time and loudness were made for both voice prostheses. In vitro measurements of airflow characteristics were also made. Following a 6- week trial, all patients provided feedback on the new voice prosthesis and the results were used to further improve the Provox NID. This final version of the new voice prosthesis was subsequently trialled and evaluated by 10 patients 6 months later. Results. Overall results showed that patient satisfaction with the Provox NID non- indwelling voice prosthesis was favourable. The pull- out force for the new prosthesis was significantly higher than that for the formerly used prosthesis and its aerodynamic characteristics were better.
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A clinical isolate of Proteus mirabilis containing R-plasmid RP1 (R+ cells), grown in both iron- and carbon- limited chemically defined media in mixed culture with plasmid-free (R- cells), did not disappear as expected, due to adherence of R+ cells to the wall of the chemostat vessel. Plasmid RP1 promoted adherence to glass and to medical prostheses. The hydrophobicity and surface charge of R+ cells were different from those of R- cells and both factors may contribute to the adherence of R+ cells to surfaces. The mode of cultivation of the cells, whether batch or continuous culture, were also found to affect the result. Antibodies raised against homologous cells increased the surface hydrophobicity of both R+ and R- cells and eliminated the differences between them. Results for surface hydrophobicity varied with the method used for measuring it. R+ cells were more sensitive than R- cells to tbe bacteridical action of normal serum and whole blood and to phagocytosis as measured by chemiluminescence. No clear differences were revealed in the protein antigens of R+ and R- cells by both SDS PAGE gels and immunoblots reacted with homologous antibodies. However, lectins revealed differences in the sugars exposed on the cell surfaces. Chemical analysis of R&43 and R- cells also revealed differences in the content of 2-keto-3-deoxy-D-manno-2-octulosonate, lipopolysaccharide and total fatty acids, when cells were grown in media containing added iron; however, no qualitative differences in the lipopolysaccharide were found. Removal of iron from the medium was found to have considerable effects on the chemical structure of R+ cells but not of R- ones. Adhesion to prostheses and to leucocytes is discussed in the light of the results and the clinical relevance outlined with respect to the initiation of infection and the association of virulence with antibiotic resistance.
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Porous structures are being widely investigated for use in biomedical implants, aiming to mechanically integrate and functionally the implant inside the bone tissue. Moreover, this structure is also important for drugs that can be stored and can induce and accelerate the process of osseointegration. With the purpose to investigate this effect, Ti, Nb and Sn metal powders, were sintered by plasma using a hollow cathode discharge. Sintering was performed in argon plasma set at 4 mbar pressure and temperatures of 500 ° C, 600 ° C and 700 ° C. Samples were also sintered in the electrical resistance furnace at 1200 ° C in order to compare plasma sintering with the conventional method. It was observed that plasma samples sintered with the hollow cathode configuration showed a gradient in porosity, while the samples sintered in the resistive furnace did not. Furthermore, differences in the microstructure of the samples were found, were a surface with higher porosity and ales porous core were obtained at different temperatures. The percolation profile of distilled water and the chemical compositions of the porous layers of the plasma treated samples were the main results obtained. Based on these results, we can conclude that this structure is particularly important for application in the biomedical field such as scaffolds for drug delivery and implants
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Työssä selvitettiin sähkötoimisten käsiproteesien nykyteknologian taso. Selvitettäviä asioita olivat keskushermoston ja proteesin välisen hermokytkennän toteutustapa, sähkötoimisten käsiproteesien keskeiset tekniset ominaisuudet sekä käsiproteesin mekaaniset toteutustavat. Tutkimus suoritettiin kirjallisuustutkimuksena. Työhön valittiin esimerkkejä kaupallisesti saatavilla olevista käsiproteeseista jotka löytyivät internetistä hakemalla kaikkein edisty-neintä käsiproteesia. Työstä rajattiin pois proteesin suora kytkeminen keskushermostoon. Liikeinformaation välitys aivoilta proteesille onnistuu mittaamalla lihassähkökäyrä erilaisilla ihon ja lihasten päälle, ihon alle lihaksien yhteyteen tai suoraan hermojen yhteyteen asete-tuilla elektrodeilla. Lihassähkökäyrän mittaamisessa ihon pinnalta on ongelmana sähkömag-neettinen säteily, hiki, joka muuttaa ihon impedanssia ja elektrodien meneminen pois paikal-taan. Ihon alle asetettavat elektrodit kapseloituvat, mikä heikentää niiden toimintaa ja nii-den ihon läpi kulkevat johdot voivat altistaa kohdan infektioille tai takertua johonkin. Her-moihin suorassa kosketuksissa olevat elektrodit aiheuttavat lisäksi hermopinteen. Kohden-netulla uudelleenhermotuksella voidaan hermosyyt johtaa lihaksiin, jolloin lihaksista saa-daan biologiset vahvistimet lihassähkökäyrää varten tai korvaavalle ihoalueelle, johon koh-distuva kosketus tuottaa tuntemuksen käteen kohdistuvasta kosketuksesta. Käden menet-tämisen myötä menetettävät hermo-ohjaustiedot voivat osittain korvautua aivojen mukau-tuvuuden ansiosta, mikä mahdollistaa tekokäden käyttämisen oppimisen samalla tavoin kuin polkupyörällä ajon. Hermotakaisinkytkentä mahdollistaa proteesin paremman hallin-nan. On mahdollista valmistaa keinoihoa johon kohdistuva paine saa aikaan muutoksen sen sähköisissä ominaisuuksissa, mitä voidaan sitten käyttää varsinaisen hermoärsytyksen luo-van laitteen, kuten tynkää ärsyttävän täryttimen, ohjaamisessa. On mahdollista valmistaa keinolihaksia joiden avulla nivelten liike voidaan toteuttaa luonnollisen kaltaisilla rakenteilla ja jotka ovat jopa kymmeniä kertoja voimakkaampia kuin aidot lihakset. Nykyteknologian avulla on mahdollista rakentaa käsiproteesi joka liikeradoiltaan, voimal-taan ja hermotakaisinkytkennän osalta vastaa lähes täydellisesti aitoa ihmiskättä. Haasteena on vielä kokeiluasteella oleva teknologian taso sekä korkea hinta.