Evaluation of polymethylmethacrylate as ocular implant in rabbits subjected to evisceration

Spheres of different types of material are used for the replacement of lost volume after removal of the eye bulb or its content to prevent contraction of the orbital cavity. The aim of this study was to evaluate the scope of polymethylmethacrylate (PMMA) used as intraocular implant in eviscerated rabbit eye. Twelve New Zealand rabbits underwent unilateral evisceration of the left eye, with subsequent implantation of PMMA sphere 12 mm in diameter. Clinical evaluation was performed daily during the first 15 days after surgery and every 15 days until the end of the study period (180 days). For the histopathological analysis, three animals per trial underwent enucleation at 15, 45, 90 and 180 days after evisceration. There was no wound dehiscence, signs of infection or implant extrusion in any animal throughout the study period. Histological examination revealed the formation of fibrovascular tissue around the implants. The PMMA behaved as inert and non-integrable.

An Electromagnetic Tracker System for the design of a dental superstructure

Nowadays, different techniques are available for manufacturing full-arch implant-supported prosthesis, many of them based on an impression procedure. Nevertheless, the long-term success of the prosthesis is highly influenced by the accuracy during such process, being affected by factors such as the impression material, implant position, angulation and depth. This paper investigates the feasibility of a 3D electromagnetic motion tracking system as an acquisition method for modeling such prosthesis. To this extent, we propose an implant acquisition method at the patient mouth, using a specific prototyped tool coupled with a tracker sensor, and a set of calibration procedures (for distortion correction and tool calibration), that ultimately obtains combined measurements of the implant’s position and angulation, and eliminating the use of any impression material. However, in the particular case of the evaluated tracking system, the order of magnitude of the obtained errors invalidates its use for this specific application.

Electromagnetic tracker feasibility in the design of a dental superstructure for edentulous patients

The success of the osseointegration concept and the Brånemark protocol is highly associated to the accuracy in the production of an implant-supported prosthesis. One of most critical steps for long-term success of these prosthesis is the accuracy obtained during the impression procedure, which is affected by factors such as the impression material, implant position, angulation and depth. This paper investigates the feasibility of 3D electromagnetic motion tracking systems as an acquisition method for modeling full-arch implant-supported prosthesis. To this extent, we propose an implant acquisition method at the patient mouth and a calibration procedure, based on a 3D electromagnetic tracker that obtains combined measurements of implant’s position and angulation, eliminating the use of any impression material. Three calibration algorithms (namely linear interpolation, higher-order polynomial and Hardy multiquadric) were tested to compensate for the electromagnetic tracker distortions introduced by the presence of nearby metals. Moreover, implants from different suppliers were also tested to study its impact on tracking accuracy. The calibration methodology and the algorithms employed proved to implement a suitable strategy for the evaluation of novel dental impression techniques. However, in the particular case of the evaluated electromagnetic tracking system, the order of magnitude of the obtained errors invalidates its use for the full-arch modeling of implant-supported prosthesis.

Accuracy Comparison of Implant Impression Techniques: A Systematic Review

Background: Several studies link the seamless fit of implant-supported prosthesis with the accuracy of the dental impression technique obtained during acquisition. In addition, factors such as implant angulation and coping shape contribute to implant misfit. Purpose: The aim of this study was to identify the most accurate impression technique and factors affecting the impression accuracy. Material and Methods: A systematic review of peer-reviewed literature was conducted analyzing articles published between 2009 and 2013. The following search terms were used: implant impression, impression accuracy, and implant misfit.A total of 417 articles were identified; 32 were selected for review. Results: All 32 selected studies refer to in vitro studies. Fourteen articles compare open and closed impression technique, 8 advocate the open technique, and 6 report similar results. Other 14 articles evaluate splinted and non-splinted techniques; all advocating the splinted technique. Polyether material usage was reported in nine; six studies tested vinyl polysiloxane and one study used irreversible hydrocolloid. Eight studies evaluated different copings designs. Intraoral optical devices were compared in four studies. Conclusions: The most accurate results were achieved with two configurations: (1) the optical intraoral system with powder and (2) the open technique with splinted squared transfer copings, using polyether as impression material.

Voxel-based registration of simulated and real patient CBCT data for accurate dental implant pose estimation

The success of dental implant-supported prosthesis is directly linked to the accuracy obtained during implant’s pose estimation (position and orientation). Although traditional impression techniques and recent digital acquisition methods are acceptably accurate, a simultaneously fast, accurate and operator-independent methodology is still lacking. Hereto, an image-based framework is proposed to estimate the patient-specific implant’s pose using cone-beam computed tomography (CBCT) and prior knowledge of implanted model. The pose estimation is accomplished in a threestep approach: (1) a region-of-interest is extracted from the CBCT data using 2 operator-defined points at the implant’s main axis; (2) a simulated CBCT volume of the known implanted model is generated through Feldkamp-Davis-Kress reconstruction and coarsely aligned to the defined axis; and (3) a voxel-based rigid registration is performed to optimally align both patient and simulated CBCT data, extracting the implant’s pose from the optimal transformation. Three experiments were performed to evaluate the framework: (1) an in silico study using 48 implants distributed through 12 tridimensional synthetic mandibular models; (2) an in vitro study using an artificial mandible with 2 dental implants acquired with an i-CAT system; and (3) two clinical case studies. The results shown positional errors of 67±34μm and 108μm, and angular misfits of 0.15±0.08º and 1.4º, for experiment 1 and 2, respectively. Moreover, in experiment 3, visual assessment of clinical data results shown a coherent alignment of the reference implant. Overall, a novel image-based framework for implants’ pose estimation from CBCT data was proposed, showing accurate results in agreement with dental prosthesis modelling requirements.

Consumo energético e eficiência da marcha com dois modelos de joelhos protésicos: estudo de caso

Introdução – Os componentes protésicos têm um papel fundamental na eficiência energética da marcha dos indivíduos amputados. Esta é uma área de conhecimento ainda em desenvolvimento, onde a investigação desempenha um papel central. Objectivos – Comparar e analisar o efeito de dois joelhos protésicos, 3R34, monocêntrico modular, de fricção constante, com auxiliar de extensão incorporado (A) e 3R92, monocêntrico modular, com travão de fricção e controlo pneumático da fase de balanço (B) no consumo energético e eficiência da marcha. Metodologia – Um indivíduo do sexo masculino de 27 anos, com amputação transfemural longa, foi sujeito a um protocolo submáximo de avaliação da resposta ao exercício em passadeira rolante (H/P/Cosmos(R) Mercury), através de um sistema de análise de gases breath‑by‑breath (Cosmed Quark PFT Ergo). Foi efetuado o mesmo protocolo com intervalo de dois dias, primeiro utilizando o joelho A e depois o B. As variáveis analisadas foram o consumo de O2 (VO2), o equivalente metabólico (MET) e a eficiência energética da marcha (Quociente de VO2 esperado de um individuo saudável e o VO2 do individuo em estudo). O esforço percecionado foi medido com a escala RPE de Borg. Resultados – O consumo energético com o joelho A (24,2 ml O2/kg/min; 6,9 MET) foi inferior ao obtido com o joelho B (28,68 ml O2/kg/min; 8,2 MET). A eficiência energética da marcha foi mais elevada para o joelho A (43%) do que para o joelho B (39%). Conclusão – A utilização do joelho A na prótese do indivíduo em estudo resulta numa marcha de menor consumo energético e maior eficiência. No entanto, este valor poderá estar influenciado pelo curto período de adaptação ao joelho B, sendo necessários mais estudos para confirmar os resultados do estudo e a influência deste fator. ABSTRACT - Background – Prosthetic components have a crucial role in the energy efficiency of amputee’s gait. This is an area of knowledge still in development, where research plays a central role. Objective – The purpose of this case study is to compare the impact in energy consumption of two prosthetic knees, titanium single‑axis constant friction knee joint with internal extension assist, 3R34 (A) and a single‑axis pneumatic swing phase control, 3R92 (B). Methodology – The participant was a transtibial amputee, male, with 27 years old, with no other clinical or functional impairments. To measure the energy expenditure a submaximal treadmill (H/P/Cosmos(R) Mercury) exercise stress test combined with a breath‑by‑breath analysis system (Cosmed Quark PFT Ergo) was used. The same test was applied to both knees, separated by two days. The analyzed variables were O2 consumption (VO2), metabolic equivalent (MET) and gait efficiency (VO2 ratio expected from a healthy individual and the studied individual). A rate of perceived exertion (Borg’s Scale) was used. Results – The results were favorable to knee A (24.2 ml O2/kg/min; 6.9 MET, 43% efficiency) compared with knee B (28.68 ml O2/kg/min; 8.2 MET, 39% efficiency). Conclusion – In this case, a less energy consumption gait corresponds to the prosthesis with knee A. These values may be influenced by the short adaptation period with knee B, so it’s necessary to perform more studies to confirm the previous results and to understand the truly impact of correct adaptation factor to the best prosthetics components for different patients.

Avaliação do perfil hemodinâmico de válvulas aórticas percutâneas: análise comparativa entre os dois dispositivos disponíveis no mercado - válvula auto-expansível e válvula expansível por balão

Mestrado em Tecnologia de Diagnóstico e Intervenção Cardiovascular. Área de especialização: Intervenção Cardiovascular.

Study and comparison of physiological response with Harmony® suspension system and suspension with pin

The purpose of this study is a cross-qualitative and quantitative gait analysis in 3 traumatic unilateral amputees using prosthesis with pin suspension compared to the use of prosthesis with a high vacuum suspension, the Harmony® system. In Portugal, there aren’t many studies made in the field of orthotic and prosthetic and knowledge about the number of amputees in the country. The only know is that the major cause of lower limb amputation is diabetes mellitus, being the most affected population the older age groups. The combination of technological developments with daily needs of the amputees is becoming more and more important for they better quality of life. This work was done during the curricular unit “Investigation in Prosthetics and Orthotics” class, in the 4th year of Health Technology School of Lisbon, in Portugal. This study analyzes if the change of suspension in transtibial prosthesis will influence some physiological response in amputees.

Perfil ecocardiográfico do doente com estenose aórtica degenerativa

Mestrado em Tecnologia de Diagnóstico e Intervenção Cardiovascular - Área de especialização: Ultrassonografia Cardiovascular.

Avaliação da integridade estrutural de uma prótese cimentada por emissão acústica

Mestrado em Engenharia Electrotécnica e de Computadores

Oral health, hygiene practices and oral cancer

OBJECTIVE: To assess the association between oral health and hygiene practices and oral cancer. METHODS: Hospital-based case-control study in the metropolitan area of São Paulo, southeastern Brazil, from 1998 to 2002. A total 309 patients with squamous cell carcinoma of the mouth and the pharynx and 468 controls matched by sex and age were included in the study. Cases were recruited in seven reference hospitals and controls were selected in five out of the seven participating hospitals. Detailed information on smoking, alcohol consumption, schooling, oral health status and hygiene practices were obtained through interviews. Odds ratios (OR) and 95% confidence intervals (95% CI), adjusted by sex, age, schooling, smoking, alcohol consumption as well as the variables oral health status and hygiene practices were estimated using unconditional logistic regression analyses. RESULTS: The use of complete dental prosthesis was not associated with oral cancer but regular gum bleeding showed a strong association (OR 3.1; 95% CI 1.2-7.9). Those who never attended a dental visit were more likely to have oral cancer (OR 2.5; 95% CI 1.3-4.8). Daily mouthwash use showed a stronger association to pharynx (OR 4.7; 95% CI 1.8-12.5) than mouth cancer (OR 3.2; 95% CI 1.6-6.3). CONCLUSIONS: Gum bleeding, no dental care, and daily mouthwash use were factors associated with oral cancer regardless of tobacco and alcohol consumption.

Estudo de caso de malformação congénita, com quantificação do êmbolo em 4 sistemas de suspensão para próteses endosqueléticas transtibiais com encaixe TSB

Introdução – O efeito de êmbolo é um dos principais problemas relacionados com a eficácia de uma prótese. Uma diminuição do mesmo pode levar a uma marcha mais natural através do aumento da propriocetividade. Objetivos – Verificar se existe diferença de valores do efeito de êmbolo entre vários sistemas de suspensão para próteses transtibiais com a utilização de Liners e testar a aplicação de testes de imagiologia na análise da melhor solução protésica para um determinado indivíduo. Metodologia – Foi obtida uma radiografia da prótese em carga na posição ortostática, mantendo o peso do indivíduo igualmente distribuído pelos dois pés. Seguidamente foi realizada outra radiografia no plano sagital com o joelho com 30° de flexão, com a prótese suspensa e um peso de 5kg aplicado na extremidade distal da mesma durante 30 seg. Através destes dois exames efetuaram-se as medições do êmbolo para cada tipo de sistema de suspensão. Resultados – Dos quatro sistemas estudados apenas três apresentam valores de êmbolo, visto que um dos sistemas não criou suspensão suficiente para suportar o peso colocado na extremidade distal da prótese. Através das medições realizadas nos exames imagiológicos dos três sistemas pudemos encontrar variações de efeito de êmbolo que vão dos 47,91mm aos 72,55mm. Conclusão – Através da realização do estudo imagiológico verificaram-se diferenças a nível do efeito de êmbolo nos vários sistemas de suspensão, provando que esta é uma ferramenta viável na avaliação do mesmo. Também através da análise dos resultados ficou notório que o sistema de suspensão Vacuum Assisted Suspention System (VASS) é o que apresenta menos êmbolo.

Choosing best components for an amputee: a methodology for the best decision-making

The harmony between the stump and the prosthesis is critical to allow it to fulfill its function enabling an efficient gait. A well fitted socket, with an efficient and comfortable suspension, allows the amputee to continue their daily living activities, maintaining the stump functional, making this correlation between socket and suspension very important in the functionality of the prosthesis, mobility and overall satisfaction with the device. Of our knowledge, the quantitative correlation between all of these factors as not yet been assessed. Aim of study: Verify and confirm the process of decision-making for four different trans-tibial prostheses with suspension systems: Hypobaric(A), PIN(B), Classic Suction(C) and Vacuum Active –VASS(D) according data provided by gait efficiency (mlO2/kg/m) imagiology (pistonning) and amputee perception.

Reabilitação auditiva e qualidade de vida dos idosos

Mestrado em Intervenção Sócio-Organizacional na Saúde - Área de especialização: Diagnóstico e Intervenção Organizacional e Comunitária

Examination timetabling automation using hybrid meta-heuristics

Trabalho de projeto realizado para obtenção do grau de Mestre em Engenharia Informática e de Computadores