Made available in DSpace on 2014-07-29T15:21:59Z (GMT). No. of bitstreams: 1 Dissertacao Washington M de Santana.pdf: 773538 bytes, checksum: 8a934007fd255f4536cfdfdbde213eb7 (MD5) Previous issue date: 2007-09-28 / The scientific literature has reported that dental implants can be affected by the oral microorganisms through the formation of a bacterial biofilm. The region most affected is the connection between the implant platform and the prosthetic abutment, particularly in implants with an external connection. Therefore, the region of the implant/abutment connection can participate in the development of peri-mucositis or peri-implantitis. They propose that these implant/abutment connections known as morse taper provide an effective seal against microorganisms. Thus the objective of this research was to evaluate the microleakage on the implant/abutment interface of internal hex and morse taper prosthetic connections. Thirty five (35) implants were selected and divided into seven (7) groups (5 groups of implants from Brazilian manufacturers and 2 groups of implants manufactured abroad). The tested implants were Straumann (Straumann AG® / Switzerland), Ankylos (Dentsply-Friadent® / Germany), AR Morse (Conexão/Sistema de Prótese® São Paulo-SP), Titamax CM (Neodent® /Curitiba-PR), Titamax II Plus (Neodent®/Curitiba-PR), Stronger (Sin/Sistema Nacional de Implante® São Paulo - SP) e Titanium Fix CM (AS Technology / São José dos Campos-SP). For the microbiological test the bacterium Enterococus faecalis (ATCC 29212) was selected. This bacterium was inoculated in the interior aspect of the implant followed by immediate installation and final torque (N/cm) of the prosthetic abutment. The implant/abutment set up was then placed in a Brain Heart Infusion broth (BHI) and incubated in this broth for 14 days. During this period, the cloudiness of the broth was evaluated at days 7 and 14. The data were statistically analyzed by the Kruskal Wallis method. The results demonstrated that all samples from both Ankylos and Neodent CM groups did not present microleakage. Although 20% of samples from Conexao AR Morse group presented microleakage, there was no significant statistical difference when compared to the former two groups. Furthermore, all samples from Straumann,Titanium Fix CM, Neodent Titamax II Plus, and SIN Strong groups presented microleakage after 14 days of culture (p=0.05), though correlation analysis among these samples did not reveal significant statistical differences. / A literatura tem ressaltado que os implantes osseointegráveis podem ser afetados por transtornos decorrentes da formação de biofilme bacteriano em sua superfície. A região acometida envolve principalmente a conexão entre a plataforma do implante e o abutment, situação evidenciada especialmente nos implantes de conexões externas. Assim, tal situação pode culminar na formação de mucosites ou até mesmo perimplantites. Alguns tipos de conexões têm sido colocados no mercado pelos fabricantes de implantes com proposta de melhor selamento microbiológico. Baseada nesta consideração, esta pesquisa teve como propósito avaliar a microinfiltração na interface implante-abutment das conexões protéticas de alguns sistemas de hexágono interno e das conexões internas conemorse, que propõem capacidade efetiva de vedamento microbiológico. Para sua execução foram selecionados 35 implantes divididos em 7 grupos (5 grupos de implantes de procedência de empresas nacionais e 2 grupos advindos de empresas importadas). Os implantes analizados foram Straumann (Straumann AG® / Switzerland) e Ankylos (Dentsply-Friadent® / Germany), AR Morse (Conexão/Sistema de Prótese® São Paulo-SP), Titamax CM (Neodent® /Curitiba-PR), Titamax II Plus (Neodent®/Curitiba-PR), Stronger (Sin/Sistema Nacional de Implante® São Paulo - SP) e Titanium Fix CM (AS Technology / São José dos Campos-SP). Para os testes de contaminação, foi selecionada a bactéria Enterococcus faecalis (ATCC 29212), sendo esta inoculada no interior do implante com a imediata instalação e torque (N/cm) do respectivo abutment (pilar protético). Posteriormente, o conjunto pilar/implante inoculado foi colocado em meio de cultura caldo infusão de cérebro e coração (BHI) e mantido neste meio por um período de 14 dias. Durante este período, o controle da contaminação indicando microinfiltração foi feito pelo turvamento do meio de cultura, avaliado aos 7 dias e aos 14 dias após inoculação. Após a coleta dos dados, foi aplicado teste estatístico pelo método não paramétrico de Kruskal- Wallis e os resultados demonstraram que todas as amostras do grupo Ankylos e Neodent CM não apresentaram microinfiltração, sendo que 20% do grupo Conexão AR Morse apresentaram microinfiltração, contudo sem apresentar diferenças estatísticas significativas quando comparados com os grupos anteriores. Ainda, as amostras dos grupos Straumann, Titanium-Fix CM, Neodent Titamax II Plus e SIN Strong apresentaram todas as amostras infiltradas após 14 dias do estudo (nível de significância alfa=0,05) e na avaliação da correlação entre estas amostras, constatou-se que não houve diferenças estatísticas significativas entre si.

L'objectif principal de tout dispositif médical implantable est d'améliorer l'état de santé du patient en lui assurant un risque minimum. Dans ce but, l'étude de l'implant rachidien B Dyn comporte plusieurs volets : - la réalisation d'un suivi clinique, - l’analyse et la proposition de solutions techniques (actions correctives), - la création d'un outil numérique pour des évolutions ultérieures (actions préventives).L’étude bibliographique initiale permet d'appréhender l'anatomie fonctionnelle du rachis lombaire, de comprendre les états pathologiques et leurs conséquences et enfin de faire un inventaire des techniques chirurgicales associées (résection osseuse, implantation de dispositifs...).Le suivi clinique d'une population de trente patients souligne ensuite les apports (somatiques et fonctionnels) du B Dyn dans sa conception première. Pour quelques cas, l'analyse des clichés radiographiques en position de flexion montre une détérioration naissante de l'anneau liée, probablement, à une surcharge accidentelle de l'implant. Ce constat impose une évolution de la conception de l'implant.Une analyse de la conception initiale et la caractérisation mécanique en traction, permettent de cibler les actions correctives à appliquer dans le cadre de cette évolution. La démarche mise en place s'appuie sur l'évaluation expérimentale pour sélectionner des solutions techniques satisfaisant aux critères fonctionnels ; elle conduit à une évolution du choix de matériau de l'anneau.Pour la réalisation d'évolutions ultérieures, un modèle éléments finis est créé. L’approche numérique se substitue ainsi à l’approche expérimentale contraignante et coûteuse. La caractérisation préalable des élastomères est nécessaire à l'obtention de données matériaux pour élaborer ce modèle. Les résultats des premières simulations d'un essai de traction sont comparés aux données expérimentales dans la perspective de la validation du modèle.A ce stade, l'étude du B Dyn propose une première solution d'évolution de l'implant et un outil numérique pour l'analyse future de solutions techniques. / The main focus of any implantable medical device is to improve the health of the patient by providing minimum risk. For this purpose, the study of the B Dyn spinal implant comprises several constituents: - The carrying out of a clinical follow up, - The analysis and choice of technical solutions (corrective actions) - The creation of a digital tool for further development (preventive actions).The initial bibliographical study enables to comprehend the functional anatomy of the lumbar spine, to understand the pathological states and their consequences and finally to list the associated surgical techniques (osseous resection, implantation of devices…).The clinical follow-up of a population of thirty patients then underlines the contributions (somatic and functional) of the B Dyn in its first design. For a few cases, the analysis of radiographs in flexion shows an incipient deterioration in the ring probably related to an accidental overloading of the implant. This observation requires an evolution in the design of the implant.An analysis of the initial design and the mechanical characterization in traction, allow targeting the corrective actions to be applied in the context of this evolution. The developed approach is based on the experimental evaluation in order to select technical solutions that would satisfy the functional criteria; this leads to an evolution of the choice of the ring material.To conduct subsequent developments, a finite element model is created. Thus the digital approach replaces the restrictive and expensive experimental approach. The preliminary characterization of elastomers is necessary to obtain materials data to work out this model. The results of the first simulations of a tensile test are compared to experimental data in the perspective of the model validation.At this stage, the B Dyn study provides a first solution of implant evolution and a numerical tool for the future analysis of technical solutions.

In order to provide evidence demonstrating the efficacy of cochlear implantation in the children enrolled in the Pretoria Cochlear Implant Programme (PCIP), an in-depth analysis of the numerous variables involved in determining each individual child’s success with his/her cochlear implant needs to be undertaken. As the PCIP has been operating for over a decade, a standardised database that includes the variables identified by similar cochlear implant programmes world-wide as being related to outcomes of children with cochlear implants and their families, has to be assembled. As the PCIP functions partly as a paediatric cochlear implant programme, an Early Communication Intervention (ECI) approach with the emphasis on the family unit is of critical importance. To address this need, a comprehensive questionnaire was used in a cross sectional study combining qualitative, and predominantly quantitative methods. The aim was to determine the perceptions of parents/caregivers of children with cochlear implants in the PCIP of the children’s outcomes. The questionnaire was further used to gather relevant data pertaining to children and their families’ biographical, medical, environmental, audiological, linguistic and educational histories and current functioning. A total of 45 participants, all mothers of children with cochlear implants, returned questionnaires. Results indicated that several key factors played a role in determining a positive outcome in the children’s audiological, linguistic, social and educational functioning leading to placement in an inclusive educational setting. These included an early age at diagnosis and prompt fitting of hearing aids and subsequent cochlear implantation, the absence of prenatal and perinatal complications including feeding difficulties, a higher level of maternal education, achievement of developmental milestones within normal age norms, the use of an FM system in the primary school phase, access to ECI, the presence of an older sibling to act as a language model, the absence of birth trauma and congenital rubella syndrome as cause of hearing loss, and later (acquired) onset of hearing loss. Children whose cause of hearing loss was non-syndromic and hereditary or unknown, were more likely to have positive outcomes. The clinical implications for the PCIP were synthesised and presented as a developmental systems model, providing guidelines for the entire process from referral to the cochlear implant programme to exiting of the system. The urgency of the need for a universal newborn or infant hearing screening programme as well as reliable systems of early referral to cochlear implant programmes, emerged strongly in the recommendations of the study. / Dissertation (M (Communication Pathology))--University of Pretoria, 2006. / Speech-Language Pathology and Audiology / Unrestricted

This thesis presents the modeling of tool data produced during ion implantation for the prediction of wafer sheet resistance. In this work, we will use various statistical techniques to address challenges due to the nature of equipment data: high dimensionality, colinearity, parameter interactions, and non-linearities. The emphasis will be data integrity, variable selection, and model building methods. Different variable selection and modeling techniques will be evaluated using an industrial data set. Ion implant processes are fast and depending on the monitoring frequency of the equipment, late detection of a process shift could lead to the loss of a significant amount of product. The main objective of the research presented in this thesis is to identify any ion implant parameters that can be used to formulate a virtual metrology model. The virtual metrology model would then be used for process monitoring to ensure stable processing conditions and consequent yield guarantees. / text

<p><span style="font-size: 8pt / " text-align:="" font-family:="" color:="">The edentulous jaw is a common feature in elderly patients that had lost their teeth during life due to local reasons such as poor oral hygiene and dental caries as well as periodontal disease. Hence these patients are the victims of biological phenomenona that lead to difficulties in different aspects of patient comfort with dentures. Clinicians are always concerned to minimize these difficulties and increase patient comfort through manufacturing a proper prosthesis to substitute for the loss of the natural teeth as well as the surrounding structures for optimum satisfaction and improved quality of life of the patient. The aim of this study was to evaluate patient satisfaction regarding function and aesthetics with conventional mandibular dentures and implant retained mandibular overdentures in denture wearers.</span></p>

Objectives: Discuss use of a linear incision for placement of a magnetically coupled bone anchored hearing implant. Methods: Case series. Results: Two patients underwent placement of magnetically coupled bone-anchored hearing implants (BAHI) through linear incisions. The first, a 40-year-old female with congenital single-sided deafness, previously had successful implantation of a percutaneous bone anchored hearing implant through a linear incision; unfortunately, she developed pain and intermittent drainage at her abutment site with time, resulting in a request for removal of her device. As an alternative to complete removal, we offered to replace the percutaneous implant with a magnetically coupled BAHI, employing the same linear incision previously. The second patient, a 53-year-old obese female with limited neck mobility and mixed hearing loss, underwent primary placement of a magnetically coupled BAHI through a linear incision. Limitations in neck mobility and patient body habitus precluded use of a traditional C-shaped incision. Both patients underwent surgery successfully, healed without incident, had their devices activated 6 weeks after their procedures, and are able to wear their implants more than 8 hours per day without discomfort. Conclusion: Surgical techniques for bone-anchored implants continue to evolve. Though manufacturers of magnetically coupled devices recommend using C-shaped incisions with large skin flaps, our first reported cases suggest that a small linear incision immediately overlying the implant magnet may be an acceptable alternative. Potential benefits include a smaller incision, less hair removal, smaller flap, decreased surgical time, and less postoperative pain.

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / The (Surgical Implant Generation Network) SIGN Intramedullary (IM) nail is designed to fix long bone fractures without using a costly C‐arm imaging device. It is distributed for free to countries in need, allowing for elevation of care from the standard, lengthy traction treatment in those countries to clinically superior IM nailing. This paper compares the clinical outcomes of the SIGN IM nail to those of the IM nails used in developed countries with use of a C‐arm. The terms “Surgical Implant Generation Network” and “union” were searched in four databases. Primary studies of SIGN IM nails were included and their outcomes, including union rate, time to union, and complications, were recorded and compared to historical data of IM nails used in developed countries. Overall, there is a similar union rate in bones fixed with SIGN IM nails (94.6%) versus bones fixed with IM nails in developed countries (92.3%) (p = 0.009, OR = 1.67), while some bone types (tibia and femur) demonstrated a lower union rate when individually stratified (p = 0.008, OR = 0.26 and p = 0.002 and OR = 0.15, respectively). Mean time to union for all bone types combined showed no significant difference between SIGN IM nails and IM nails used in developed countries (p = 0.26). Complications rates were similar between SIGN IM nails and IM nails used in developed countries. It is possible for the SIGN IM nail to be used to fix long bone fractures in developing countries with outcomes comparable to the IM nail used in developed countries.

Laser surface modification of AZ31B Magnesium alloy changes surface composition and roughness to provide improved surface bio-wettability. Laser processing resulted in phase transformation and grain refinement due to rapid quenching effect. Furthermore, instantaneous heating and vaporization resulted in removal of material, leading the textured surface generation. A study was conducted on a continuum-wave diode-pumped ytterbium laser to create multiple tracks for determining the resulting bio-wettability. Five different laser input powers were processed on Mg alloy, and then examined by XRD, SEM, optical profilometer, and contact angle measurement. A finite element based heat transfer model was developed using COMSOL multi-physics package to predict the temperature evolution during laser processing. The thermal histories predicted by the model are used to evaluate the cooling rates and solidification rate and the associated changes in the microstructure. The surface energy of laser surface modification samples can be calculated by measuring the contact angle with 3 different standard liquid (D.I water, Formamide, and 1-Bromonaphthalen). The bio-wettability of the laser surface modification samples can be conducted by simulated body fluid contact angle measurement. The results of SEM, 3D morphology, XRD, and contact angle measurement show that the grain size and roughness play role for wetting behavior of laser processing Mg samples. Surface with low roughness and large grain size performs as hydrophilicity. On the contrast, surface with high roughness and small grain size performs as hydrophobicity.

The purpose of this study was to determine what factors influence dentists when deciding whether to place an implant or perform endodontic retreatment. Null hypothesis: Dentists today are no more likely to place an implant than to perform endodontic retreatment. A twelve-item questionnaire was mailed to 525 general dentists and specialists who are members of the Richmond Dental Society. Response rate was 61.9%. The questionnaire included items on demographics, practice profile and cases of failing endodontic therapy which participants were asked to consider and chose between endodontic retreatment or implant placement. The relationship between the treatment choices and the characteristics of each dentist was assessed using a chi-square analyses and logistic regression analyses. Generally practitioners preferred retreatment (66%). This preference for retreatment varied between 25.5% and 85.9%. Associations were found between years of experience and implant use. In those practitioners with 10 years or less experience the odds of choosing an implant were higher than practitioners with more than 10 years of experience. Associations were also found between those who place implants vs. those who do not. The odds of choosing an implant verses retreatment were lower in those who did not place implants versus those who did. In conclusion, it appears that clinicians participating in this study in general still consider endodontic retreatment to be a viable treatment option prior to implant placement. However, this varies greatly with years of experience and the use of implants in practice.

Clinicians have described the success rates of dental implants. The use of implants is projected to increase in the future. With a 5-10% failure rate, it is unclear the exact factors that are associated with implant failures. To improve upon these success rates, it is critical to understand parameters associated with implant failure including: periodontitis, peri-implantitis, systemic diseases, site preparation, dental history of the implant site, bone quality, materials, occlusion, and treatment timelines. While bone quality is associated with failure, objective measures to assess bone quality and characteristics are scarce. Therefore, the aim of this study is to determine whether possible comorbidities, associated dental parameters, and measurable bone quality are possible predictors of implant failure. In this study, we utilized the electronic health record system axiUm® to retrospectively investigate non-failed (NF) and failed (F) dental implants from a patient cohort with 149 implants placed between 2012-2015 at Virginia Commonwealth University School of Dentistry. A chart review was conducted extracting information on age, gender, systemic diseases, smoking, occlusal trauma, parafunction, bone grafting history, treatment timelines, implant site/type/placement protocol, infection, torque at placement, bone quality and microarchitecture assessed by the novel, innovative technology: trabecular bone score (TBS). A total of 149 implants, 46 failures and 105 non-failed controls, were selected based on similar implant sites. Preliminary data obtained from analysis suggests that average time from implant placement to failure was 6.6 months (0.55 years). Parafunction habit (p=0.0202) and increased number of implants (p=0.0478) were found to be associated with increased implant failure.