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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Proxy-based prefetching and pushing of web resources / Proxy-baserad prefetching och pushing av web resurser

Holm, Jacob January 2016 (has links)
The use of WWW is more prevalent now than ever. Latency has a significant impact on the WWW, with higher latencies causing longer loading time of webpages. On the other hand, if we can lower the latency, we will lower the loading time of a webpage. Latencies are often caused by data traveling long distances or through gateways that add additional processing delays to the forwarded packets. In this thesis we evaluate the latency benefits of different algorithms for prefetching and pushing of web resources, from a proxy when the client cache is known. We found that the most beneficial algorithm is a two sequence data mining technique. This algorithm is evaluated on a live system where we improve loading time by approximately 246 ms with only a 27% traffic increase on average. The results were measured by evaluating a large set of clients on Opera Turbo 2, a distributed proxy with knowledge of the client’s cache. We also concluded that by using a more conservative strategy we can push prefetched resources to the client, reducing the client requests by approximately 9.3% without any significant traffic increase between proxy and client.
122

Migrerande Mönster : En komparativ-kvantitativ studie om stadsförsamlingarna Kalmar och Karlskronas migration under 1900-talets första halvsekel. / Migratory Patterns : A comparative-quantitative study on the migration of the city parishes Kalmar and Karlskrona during the first half of the 20th century.

Lahti, Izabelle, Nilsson, Moa January 2023 (has links)
This essay aims to explore the migration from Kalmar and Karlskrona city parishes during the first half of the 20th century divided into three intervals 1915-1920, 1930-1935 and 1943-1948. As stated above the main part of the study aims to map the migration flows to and from Kalmar and Karlskrona and furthermore compare the empirical data to Swedish national statistics. To be able to correctly compare the data gathered the empirical data of the essay is divided into four variables; age, sex, professional or other titles and whether the individuals migrated alone or with family. A comparison between Kalmar, Karlskrona and national statistics will be made to investigate whether the two city parishes are able to act as representations of the national statistics or if the two city parishes have a different outcome than what the national statistical data presents. The results show that the migratory patterns differ both between Kalmar and Karlskrona and in the national statistics of migration in regard to the city parishes. With the usage of migration theories and perspectives such as the migration transition, secondary labor market theory and push- and pull perspective and concepts such as voluntary migration and chain migration the study was able to both analyze and understand the data provided from the city parishes archives
123

Samma arbetsplats – nya förutsättningar : En kvalitativ studie om konsulters erfarenheter av sina arbetsvillkor i Individ- och familjeomsorgen i socialtjänsten / Same establishment – new prerequisites : A qualitative study in consultant.s experiences of their work conditions within the individual- and family care sector of the social services

Forsberg, Ann-Kristin, Jacobsen, Malin January 2016 (has links)
Trots många års larmande av den rådande arbetsmiljön för socialarbetare har inte kommunerna agerat tillräckligt, vilket har lett till svårigheter att rekrytera och få personal att stanna kvar i socialtjänsten. Detta har bidragit till att konsulter inom socialtjänsten har ökat markant de senaste åren. Den här studien handlar om konsulters erfarenheter av sina nya arbetsvillkor då de valt att stanna kvar och arbeta i socialtjänsten inom Individ- och familjeomsorg (IFO). Syftet med studien är att öka kunskapen om vilka positiva och negativa faktorer som konsulter erfar med sina villkor i sitt arbete. Vi har utgått från en kvalitativ design och gjort semistrukturerade intervjuer med sex konsulter. De teoretiska analysverktyg vi använt oss av är rollteori, organisationsteori samt push-and-pull modellen. Dessa analysverktyg ger olika synvinklar på konsulters villkor inom IFO och lyfter fram olika faktorer i deras arbetsvillkor samt förklarar hur det är att stå utanför socialtjänsten som organisation samtidigt som de arbetar i den. I studien har vi kommit fram till att konsulternas förändring ger både positiva och negativa erfarenheter i deras arbetsvillkor som konsulter i IFO. Positiva faktorer som konsulterna erfor i sina arbetsvillkor var: Den ökade lönen, tidsbegränsningen i uppdraget, den minskade tid för antalet obligatoriska möten som genererade i ökad tid till klientarbete. De erfor mer självständighet och personlig utveckling. Det dubbla chefskapet från arbetsplatsen och konsultbolaget kunde upplevas positivt med exempelvis uppskattning och stöd i gränssättning av arbetsmängden från konsultchefen. De negativa faktorerna som konsulterna kunde uppleva i deras arbetsvillkor var ensamarbete och för höga förväntningar på prestation samt att konsulterna fick en mindre påverkningsmöjligheter i organisationen. Vi tolkade även att det kunde bli en större anpassning från konsulten till hur chefen vill att arbetet ska utföras. / Despite many years of alarming environment within the current workplace of social workers the municipalities have still not acted accordingly, which have caused hardship in recruiting as well as keeping people in the social services. This has also lead towards a large growth of consultants within the social services under the last few years. This study is about consultant’s experiences of their new work conditions when they have chosen to stay within the Individual- and family care sector (IFO). The purpose of the study is to further increase the knowledge of which negative and positive aspects consultants experience within their work conditions. We have worked with a qualitative design and made semiconstructed interviews with six different consultants. The theoretical analysis tools we have used during this study is roll theory, organization theory and the push-and-pull model. These analysis tools give different viewpoints of consultant’s conditions within IFO and brings forward the factors in these conditions, as well as describes how it can be to stand on the outside of the social services as an organization but at the same time work in it. We have concluded that these changes have caused both positive and negative experiences in consultants work conditions within the IFO. The positive factors that the consultants described were: Increased pay, limits in the assignment, the reduced time for obligatory meetings which resulted in more time for client based work as well as feeling more of a personal development. Having two employers was described as being positive with examples as appreciation and support in setting limits for a reasonable amount of work from the consulting firm. The negative aspects we found that the consultants could experience was feelings of working alone and expectations on high performance as well as having less influence in the organization overall. We concluded that the consultant was more influenced by their employers in how their work should be performed.   Keyword: consultant, social worker, profession, social service, roll theory, organisation theory, push-and-pull-model.
124

Web Font Optimization for Mobile Internet Users : A performance study of resource prioritization approaches for optimizing custom fonts on the web

Nygren, Maria January 2019 (has links)
According to the HTTP Archive, 75% of websites are using web fonts. Multiple conditions have to be met before modern web browsers like Chrome, Firefox and Safari decide to download the web fonts needed on a page. As a result, web fonts are late discovered resources that can delay the First Meaningful Paint (FMP). Improving the FMP is relevant for the web industry, particularly for performance-conscious web developers. This paper gives insight into how the resource prioritization approaches HTTP/2 Preload and HTTP/2 Server Push can be used to optimize the delivery of web fonts for first-time visitors. Five font loading strategies that use HTTP/2 Server Push and/or Preload were implemented on replicas of the landing pages from five real-world websites. The font loading strategies were evaluated against each other, and against the non-optimized version of each landing page. All the evaluated font loading strategies in this degree project improved the time it took to deliver the first web font content to the user’s screen, resulting in a faster FMP. It was also discovered that HTTP/2 Server Push, on its own, is not a more performance efficient resource prioritization approach than HTTP/2 Preload when it comes to delivering web font content to the client. Further, HTTP/2 Server Push and HTTP/2 Preload appears to be more efficient when used together, in the context of optimizing the delivery of web font content. However, all conclusions in this paper are based on the results gathered from testing the font loading strategies in an emulated environment and are yet to be confirmed on actual mobile devices with real network conditions.
125

Propuesta de mejora en el sistema de planeamiento y control de la producción en una empresa metalmecánica / Proposal for improvement in the planning and control system of production in a metalworking company

Gilham Celis, Adriana Catherine 15 April 2019 (has links)
El presente proyecto propone disminuir el stock de producto terminado y el IR empezando por los cinco productos VIP (electrodos revestidos convencionales); debido a que el stock promedio actual se encuentra en 350 ton mientras que la meta de la empresa es de 200 ton; asimismo, el IR actual es de 1.92 vueltas y se quiere llegar a un IR de 3 vueltas; generando así un impacto económico de $177,237 en promedio al cierre de cada mes en valor de inventarios. Para esto, se analiza los procesos de planeamiento y control de la producción y los estándares y políticas establecidas en la empresa. El desarrollo de este informe va de acuerdo a los planteamientos teóricos investigados en artículos de investigación publicados en revistas y libros por varios actores con experiencia en inventarios. Cabe mencionar que este proyecto se centra fundamentalmente en aplicar la metodología Lean Manufacturing usando la herramienta Kanban Pull System, puesto que se vio que la causa principal es que actualmente presenta una política de planeamiento en función a la capacidad de planta (Sistema “Push”). Por último, se validó la viabilidad de la propuesta de mejora mediante una propuesta de simulación, una propuesta teórica, comparación de indicadores y flujo económico. Del análisis anterior, se obtuvo que la Productividad aumentó de 286 a 301 kg/hh, la cantidad de operarios disminuyó de 117 a 90, la capacidad de planta disminuyó de 74 a 59 ton, y el periodo de recuperación de la inversión del proyecto es de 0.33 meses. / The present project proposes to reduce the stock of finished product and the IR starting with the five VIP products (conventional coated electrodes); because the current average stock is at 350 tons while the company's goal is 200 tons; likewise, the current IR is 1.92 laps and you want to reach an IR of 3 laps; thus generating an economic impact of $ 177,237 on average at the end of each month in value of inventories. For this, the processes of planning and control of production and the standards and policies established in the company are analyzed. The development of this report is in accordance with the theoretical approaches investigated in research articles published in journals and books by several actors with experience in inventories. It is worth mentioning that this project focuses mainly on applying the Lean Manufacturing methodology using the Kanban Pull System tool, since it was seen that the main cause is that it currently presents a planning policy based on plant capacity (Push System). Finally, the viability of the improvement proposal was validated through a simulation proposal, a theoretical proposal, comparison of indicators and economic flow. From the previous analysis, it was obtained that the Productivity increased from 286 to 301 kg / hh, the number of workers decreased from 117 to 90, plant capacity decreased from 74 to 59 tons, and the recovery period of the project investment is of 0.33 months. / Tesis
126

Dispersão Raman de um sistema doador-aceptor em diferentes solventes / Raman dispersion of a donor-acceptor system in different solvents

Carli, Fernanda Pereira 16 August 2016 (has links)
Sistemas push-pull são caracterizados pela presença de uma transição eletrônica de transferência de carga, o que justifica a grande diferença de polaridade entre os estados fundamental e excitado. Isso os torna sondas moleculares promissoras para a obtenção de informações espectroscópicas sobre a fase condensada. Alguns desses sistemas apresentam modos vibracionais cuja frequência depende da energia de excitação nos espectros Raman. Neste estudo, através de uma sonda molecular push-pull, objetivou-se analisar as características do meio que definem tal dependência. A sonda utilizada, 4-dimetilamino-β-nitroestireno apresentou deslocamento batocrômico no espectro de absorção eletrônico e a dependência da largura de banda com o solvente, o que mostrou sua sensibilidade ao meio, juntamente com uma dependência do modo de estiramento simétrico do grupo nitro com o solvente. Através do modelo do estado de solvatação seletivo, variando a energia de excitação do laser, foi possível observar a dependência do número de onda do modo de estiramento simétrico do NO2. Essa dependência foi, no entanto, mais significativa em solventes próticos polares, os quais apresentam os maiores valores de tempo de relaxação do solvente. Alguns solventes polares apróticos também apresentaram, mas com menor deslocamento, o que poderia estar relacionado com o tempo de relaxação. Solventes com dinâmicas de solvatação mais lentas e com forte interação, provocando uma diminuição na energia de transição eletrônica, são os principais fatores para ocorrência da dispersão Raman em sistemas push-pull. / The push-pulls systems are characcterized by the presence of a charge transfer electronic transition, it explain the large difference in polarity between the ground and excited states. They are promising molecular probes to obtain spectroscopic information on the condensed phase because of that characteristic. Some of these systems have vibrational modes whose frequency depends on the excitation energy in the resonant Raman spectra. The objective of this study was to analyze the vibrational frequency dependence of the molecular probe caused by environment. The 4-dimethylamino-β-nitrostyrene as a probe was sensitive to the medium showing bathochromic shift on electronic spectrum and bandwidth dependence with the solvent as well as the dependency of the nitro symmetric stretching mode in the vibrational spectrum. Based on the selective solvation state model, the laser excitation energy was varied and the dependence of the wave number of the symmetric stretching mode NO2 was observed. This dependency is, however, more significant in polar protic solvents which have the highest relaxation time values of the solvent. Some aprotic polar solvents presented that characteristic with less degree, which may be related to the relaxation time. The main factor for the occurrence of Raman scattering in push-pull solvation systems is the slower solvation dynamics and strong interaction that are capable to diminishing the energy electronic transition. The main factors for the occurrence of Raman dispersion in push-pull solvation systems are the slower solvation dynamics and strong probe/solvent interaction that are capable to diminishing the electronic transition energy.
127

Fatores que influenciam na resistência de união - ensaios push out e pull out - de pinos intra-radiculares. Estudo in vitro / Factors that influence on fiber post bond strength - push out and pull out tests. In vitro study

Nagase, Denis Yudi 03 July 2012 (has links)
Objetivo: Este estudo se propõe a verificar a influência do adesivo, material de preenchimento e hibridização da dentina na força de retenção de pinos intra-radiculares na técnica direta indireta e comparar o teste de tração de push out com o pull out. Métodos: 60 raízes de dentes bovinos com comprimento de 12 mm foram tratadas endodonticamente e divididas aleatoriamente em 6 grupos (n=10): grupo 1 (técnica direta-indireta, adesivo fotopolimerizável, cimento resinoso, teste de pull out); grupo 2 (idem ao grupo 1 porém o cimento resinoso foi substituído pela resina composta); grupo 3 (idem ao grupo anterior porém o adesivo fotopolimerizável foi substituído pelo químico); grupo 4 (idem ao anterior porém o teste utilizado foi o de push out); grupo 5 (idem ao grupo anterior porém o adesivo utilizado foi o auto condicionante); e grupo 6 (idem ao grupo anterior porém a dentina foi pré hibridizada). A força de retenção foi determinada através do teste de tração usando Universal Testing Machine (Instron). Todos os dados foram analisados usando one-way analysis of variance (ANOVA) com a significância de p<0.05 e complementadas com teste de Tukey. Após o teste, as interfaces adesivas onde ocorreram as falhas foram examinadas e classificadas. Resultado: Houve diferença estatística na comparação de materiais (adesivo, material de preenchimento). A hibridização da dentina não apresentou melhoras na retenção dos pinos . A maior parte das fraturas ocorreu na interface dentina/resina. Conclusão: Com base nos resultados obtidos, concluímos que material de preenchimento, o tipo de adesivo, influenciaram na retenção de pinos de fibra; e a pré-hibridização da dentina não apresentou melhoras a retenção dos pinos. O teste de push out apresentou mais detalhes para verificar o valor da adesão de cada terço da raiz; e o teste de pull out, para a força de retenção do pino ao longo do interior do conduto e o tipo de falha. / Objective: The aims of this study is to verify the influence of adhesive, filling material and dentin hybridization on fiber post retention force in diretc -indirect technique and compare the tensile test of push out with pull out. Methods: 60 bovine single roots with a length of 12 mm were endodontically treated and randomly divided into 6 groups (n = 10): group 1 (direct-indirect technique, light-curing adhesive, resin cement, pull out test), group 2 (same as group 1 but the resin cement was replaced by composite resin), group 3 (same as previous group but the light-curing adhesive was replaced by the chemical), group 4 (same as group 3 but the test was used was push out test), group 5 (same as group 4 but the adhesive used was the self etching) and Group 6 (same as previous group but the dentin was pre-hybridized). The retention force was determined by Universal Testing Machine (Instron). All data were analyzed using one-way analysis of variance (ANOVA) with significance of p <0.05 and complemented with Tukey test. After testing, the adhesive interfaces were examined and classifie. Result: There was a significant difference between comparison of materials (adhesive and filling material). The hybridization of dentin showed no improvement in the retention post. Most fractures occurred at the interface dentin / resin. Conclusion: Based on the results, we conclude that filling material, adhesive, influenced the retention of fiber posts, and the prehybridization of dentin did not improve the retention of fiber post. The push out test showed more details to verify the bonding between the post and dentin, and the pull out test for the retention force of the post inside the canal.
128

Estratégia de planejamento de produção e os sistemas ERP em ambientes sujeitos ao fenômeno hockey-stick. / Production planning strategy and ERP systems in environments subject to the hockey-stick phenomenon.

Basso, Renato Gioielli 18 August 2015 (has links)
O ambiente competitivo atual tem colocado pressão no processo de tomada de decisão no mundo corporativo. Os trade-offs das prioridades competitivas discutidos na elaboração da estratégia como custo, qualidade, serviço e flexibilidade já não são suficientes. Estes trade-offs, embora importantes no curto prazo, devem ser compatibilizados de modo que as empresas que tenham o melhor balanço entre eles devam ter resultado superior. Um dos trade-offs bastante discutido é o equilíbrio entre serviço e estoque. A percepção é que seja improvável alcançar excelência no serviço sem ter um considerável nível de estoque. Deste cenário nasce então o paradoxo do uso de sistemas MRP (Material Requirement Planning) versus sistemas JIT (Just in Time), ou melhor, sistemas empurrados versus puxados, já que a escolha por um ou outro sistema tem ligação íntima com a gestão de estoque. Se por um lado os sistemas MRP são largamente utilizados, via softwares ERP, por outro sistemas JIT têm trazido importantes melhorias nos resultados. Embora muitas empresas considerem a adoção exclusiva de um ou outro sistema, algumas delas têm adotado um processo híbrido com o objetivo de tirar o melhor de cada sistema e gerar assim desempenho superior. O objetivo deste trabalho é investigar como as empresas inseridas em mercados caracterizados pela concentração de demanda no final do mês (fenômeno conhecido como hockey-stick), e baixo acerto nas previsões de demanda, estão aplicando suas estratégias de planejamento de produção e seus ERP. Se por um lado a baixa acurácia nas previsões causa um problema na aplicação de estratégias empurradas de planejamento, pois requer um alto estoque de segurança associado, por outro a concentração de embarque dificulta a adoção de uma estratégia puramente puxada, já que o sistema não tem a estabilidade necessária. Para cumprir com este objetivo seis estudos de caso foram conduzidos e os resultados encontrados, suportados pela teoria, sugerem o aparecimento de um modelo híbrido eficaz para planejamento no ambiente estudado assim como o aparecimento de um sistema DSS (Decision Support System). Outra contribuição desta pesquisa foi identificar, em um dos casos, uma empresa que conseguiu atacar de maneira eficaz o fenômeno em sua causa raiz neutralizando assim seus efeitos. / The highly competitive environment of modern times has put pressure on the decision-making process in the corporate world. The trade-offs of competitive priorities such as cost, quality, service and flexibility are no longer enough. These trade-offs, albeit important in the short term, must be matched so that companies that have the best balance between them should have superior results. One of the tradeoffs widely discussed is the balance between service level and inventory. The perception is that excellence is not likely to be achieved in service without having a significant level of inventory. From this scenario comes the paradox of using MRP systems (Material Requirement Planning) versus JIT systems (Just in Time), or rather \"pushed\" systems versus \"pulled\" systems since the option for one or the other system has a close connection with inventory management. On the one hand, MRP systems are widely used in industry through ERP software; on the other hand, JIT systems have obtained better results. While many companies consider adopting one or another system, some of them adopt a hybrid process with the goal of taking the best of each system and generate superior performance. The purpose of this research is to investigate how companies inserted in markets characterized by sales peak at the end of the month (hockey-stick phenomenon), and low accuracy in demand forecasts, are applying their production planning strategies and their ERP. Low forecast accuracy causes a problem in applying pushed strategies as it requires a high safety stock associated. Conversely, the sales peak hinders the adoption of a purely pull strategy since the system does not have the necessary stability. To meet this goal, six case studies were conducted and the results found and supported by the theory suggest the emergence of an effective hybrid model for planning in the environment studied as well as the appearance of a DSS (Decision Support System). Another contribution of this research was to identify in one of the cases a company that managed to effectively tackle the phenomenon in the root cause, neutralizing its effects.
129

Influência do operador e agente cimentante na resistência de união de pinos de fibra de vidro à dentina radicular / Influence of the operator skill and luting agent on the bond strength of glass fiber post to radicular dentin.

Gomes, Giovana Mongruel 22 February 2010 (has links)
Made available in DSpace on 2017-07-24T19:22:11Z (GMT). No. of bitstreams: 1 Giovana Mongruel Gomes.pdf: 1282438 bytes, checksum: 3923d5e2e659866f5b3a3e842b6cceb4 (MD5) Previous issue date: 2010-02-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this study was to evaluate the influence of the operator skill and resin cement system on the bond strength (BS) of glass fiber post to radicular dentin in different root thirds. Forty-eight extracted human upper central incisors were sectioned transversally immediately below the cement-enamel junction and the roots were treated endodontically. After one week, standardized post space cavities were prepared, and the roots randomly divided into two groups (n=24), according to the operator skill: professional (CD) vs academic (AC). The roots were then subdivided into three subgroups (n=8) according to the cementation system: CD1 and AC1 (Adper Scotchbond Multi-Purpose [SBMP] + RelyX ARC [ARC]), CD2 and AC2 (Adper Single Bond 2 [SB] + ARC) and CD3 and AC3 (RelyX U100 [U100]). The glass fiber post (Tenax Fiber Trans Esthetic Post System) were cemented following the manufacturer’s instructions of each cementation system. After water storage at 37o C for one week, each root was sectioned transversely into six 1-mm thick discs and the coronal (TC), middle (TM) and apical (TA) thirds of the root canal identified. A push-out test was carried out at a crosshead speed of 0,5 mm/min. The data were statistically analyzed by ANOVA and post-hoc Tukey's tests (p=0.05). The mean bond strengths (BS) values (MPa) and standard deviations (SD) of each subgroup were: CD1: 12.83±7.26; CD2: 11.46±4.22; CD3: 14.27±6.59; AC1: 9.70±4.37; AC2: 8.02±5.25 and AC3: 13.40±4.93. The BS of the CD and AC groups were 12.85±6.18 and 10.37±5.30, respectively. In regard to the root thirds, the means and SD were: TC: 14.46±5.55; TM: 10.04±5.07 and TA: 10.35±6.01. The mean and SD for the cementation systems were: SBMP + ARC: 11.27±6.13; SB + ARC: 9.74±5.03 and U100: 13.83±5.77. The highest BS means were obtained for CD group (p=0.004); no significant differences were detected among the three cementation systems for CD group (p=0.294); U100 cement reached statistically higher BS than the other cementation systems for AC group (p=0.001). The resin cement U100 was statistically higher than the other materials (p=0.0010) regardless the operator skill. The BS in the cervical third was statistically higher than in the TM and TA (p<0.0001). It can be concluded that the bond strength to the root canal is significantly affected by the operator skill, cementation system and root region. / O propósito desse estudo foi avaliar a influência do operador e do sistema de cimentação na resistência de união (RU) de pino de fibra de vidro à dentina radicular nos diferentes terços radiculares. Quarenta e oito incisivos centrais superiores humanos extraídos foram seccionados transversalmente imediatamente após a junção cemento-esmalte, e as raízes foram tratadas endodonticamente. Após uma semana, foi realizado o preparo padronizado dos condutos, e as raízes foram aleatoriamente divididas em dois grupos (n=24), de acordo com o operador: profissional (CD) vs acadêmico (AC). As raízes foram então subdivididas em três subgrupos cada (n=8) de acordo com o sistema de cimentação: CD1 e AC1 (Adper Scotchbond Multi-Purpose [SBMP] + RelyX ARC [ARC]), CD2 e AC2 (Adper Single Bond 2 [SB] + ARC) e CD3 e AC3 (RelyX U100 [U100]). Os pinos de fibra de vidro (Tenax Fiber Trans Esthetic Post System) foram cimentados de acordo com as recomendações dos fabricantes de cada sistema de cimentação. Após o armazenamento em água a 37o C por uma semana, cada raiz foi seccionada transversalmente em seis discos com 1 mm de espessura, e os terços coronário (TC), médio (TM) e apical (TA) do canal radicular foram identificados. O teste de push-out foi realizado a uma velocidade de 0,5 mm/min. Os dados obtidos foram analisados estatisticamente por meio do teste ANOVA e pós teste de Tukey (p=0,05). Os valores médios de RU (MPa) e desvio padrão (DP) para cada subgrupo foram: CD1: 12,83±7,26; CD2: 11,46±4,22; CD3: 14,27±6,59; AC1: 9,70±4,37; AC2: 8,02±5,25 e AC3: 13,40±4,93. A RU e DP para o grupo dos CD e dos AC foram 12,85±6,18 e 10,37±5,30, respectivamente. Em relação aos terços radiculares, as médias e o DP foram: TC: 14,46±5,55; TM: 10,04±5,07 e TA: 10,35± 6,01. As médias e DP para os sistemas de cimentação foram: SBMP + ARC: 11,27±6,13; SB + ARC: 9,74±5,03 e U100: 13,83±5,77. As maiores médias de RU foram obtidas para o grupo dos CD (p=0,004); não houve diferenças significativas entre os três sistemas de cimentação para o grupo dos CD (p=0,294); o cimento U100 foi estatisticamente superior aos demais sistemas de cimentação para o grupo dos AC (p=0,001). O cimento resinoso U100 foi estatisticamente superior aos demais sistemas de cimentação (p=0,001) independente do operador. A RU no terço coronário foi estatisticamente superior aos TM e TA (p<0,0001). Pode-se concluir que a resistência de união do canal radicular foi significativamente afetada pelo operador, sistema de cimentação e região radicular.
130

INFLUÊNCIA DA TRANSLUCIDEZ DE PINOS DE FIBRA DE VIDRO E TEMPO DE FOTOATIVAÇÃO DE UM CIMENTO DUAL NA RESISTÊNCIA DE UNIÃO À DENTINA RADICULAR / Influence the translucence of glass fiber posts and time of photoactivation of a dual cement bond strength to root dentin

Villa, Felipe Augusto 27 February 2012 (has links)
Made available in DSpace on 2017-07-24T19:22:21Z (GMT). No. of bitstreams: 1 Felipe Villa Verde.pdf: 899114 bytes, checksum: 339db35f81d16c1053ac909db81b72f5 (MD5) Previous issue date: 2012-02-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this study was to evaluate in vitro through the push-out test, if the use of opaque glass fiber posts (Exacto – Angelus [PO]) and translucent (Exacto Translucent – Angelus [PT]), adhesively cemented into the root with dual resin cement (Variolink II - Ivoclar Vivadent) under different polymerization time had an influence on the bond strength in three different root canal thirds. Forty-eight singlerooted extracted human premolars were selected from the Tooth Bank UEPG for research. They had their crowns sectioned to form roots with 15 mm in length. All teeth received endodontic treatment and then were divided into 6 groups (n=8), to receive the cementation according to the type of glass fiber post (opaque vs.translucent) and the time of photoactivation of resin cement (20, 40 and 60 seconds). After storage in water at 37° C for one week, the teeth were embedded in acrylic resin and sectioned perpendicular to its long axis to form discs 1 mm thick, with two discs for each root third, and then were taken to the machine universal testing. The push-out test was performed at a speed of 0.5 mm/min. The data were statistically analyzed by ANOVA and Tukey's test (p = 0.05). The mean values of bond strength (MPa) and standard deviation (SD) for groups in the cervical third, middle and apical regions were: PO20 - 21.02 ± 3.52, 15.83 ± 4.94 and 5.20 ± 10:48; PO40 - 14.42 ± 3.98, 12.12 ± 4.40 and 11.59 ± 4.89; PO60 - 16.27 ± 7.14, 13.33 ± 5.22 and 16.99 ± 7.82; PT20 - 18.34 ± 5.47, 10.83 ± 4.63 and 9.98 ± 4.76; PT40 - 17.51 ± 6.55, 14.06 ± 3.85 and 10.95 ± 4.65; PT60 - 19.42 ± 5.86, 15.35 ± 5.43 and 12.77 ± 5.93). There were no significant differences between the types of fiber posts used and the different times of polymerization (p>0.05) in relation to the root area were statistically significant differences only between the cervical and the other thirds (p>0.05). It can be concluded that the bond strength of the root canals was not affected by the type of glass fiber post (opaque vs. translucent) and photoactivation time. / O objetivo deste estudo in vitro foi avaliar por meio do teste de push-out, se a utilização de pinos de fibra de vidro opaco (Exacto – Angelus [PO]) e translúcido (Exacto Translúcido – Angelus [PT]), cimentados adesivamente no canal radicular com cimento resinoso de presa dual (Variolink II – Ivoclar Vivadent) sob diferentes tempos de fotoativação apresentavam influência na resistência de união nos três diferentes terços do canal radicular. Quarenta e oito pré-molares unirradiculares humanos extraídos foram selecionados no Banco de Dentes da UEPG para a pesquisa. Tiveram suas coroas seccionadas para formar raízes com 15 mm de comprimento. Todos os dentes receberam tratamento endodôntico e em seguida foram divididos em 6 grupos (n=8), para receber a cimentação de acordo com o tipo de pino de fibra de vidro (opaco vs translúcido) e com o tempo de fotoativação do cimento resinoso (20, 40 e 60 segundos). Após o armazenamento em água a 37o C por uma semana, os dentes foram embutidos em resina acrílica e seccionados perpendicularmente ao seu longo eixo para formar discos de 1 mm de espessura, sendo 2 discos para cada terço radicular, e em seguida foram levados à máquina de ensaios universal. O teste de push-out foi realizado a uma velocidade de 0,5 mm/min. Os dados obtidos foram analisados estatisticamente por meio do teste ANOVA e pós-teste de Tukey (p=0,05). Os valores médios de RU (MPa) e desvio padrão (DP) para os grupos nos terços cervical, médio e apical foram respectivamente: PO20 – 21,02 ± 3,52, 15,83 ± 4,94 e 10,48 ± 5,20; PO40 – 14,42 ± 3,98, 12,12 ± 4,40 e 11,59 ± 4,89; PO60 – 16,27 ± 7,14, 13,33 ± 5,22 e 16,99 ± 7,82; PT20 – 18,34 ± 5,47, 10,83 ± 4,63 e 9,98 ± 4,76; PT40 – 17,51 ± 6,55, 14,06 ± 3,85 e 10,95 ± 4,65; PT60 – 19,42 ± 5,86, 15,35 ± 5,43 e 12,77 ± 5,93. Não foram observadas diferenças significativas entre os tipos de pino de fibra utilizados e os diferentes tempos de fotoativação (p > 0,05); em relação à região radicular foram encontradas diferenças estatisticamente significativas somente entre o terço cervical e os demais terços (p > 0,05). Pode-se concluir que a resistência de união do canal radicular não foi afetada pelo tipo de pino de fibra de vidro (opaco vs translúcido) e tempo de fotoativação. O objetivo deste estudo in vitro foi avaliar por meio do teste de push-out, se a utilização de pinos de fibra de vidro opaco (Exacto – Angelus [PO]) e translúcido (Exacto Translúcido – Angelus [PT]), cimentados adesivamente no canal radicular com cimento resinoso de presa dual (Variolink II – Ivoclar Vivadent) sob diferentes tempos de fotoativação apresentavam influência na resistência de união nos três diferentes terços do canal radicular. Quarenta e oito pré-molares unirradiculares humanos extraídos foram selecionados no Banco de Dentes da UEPG para a pesquisa. Tiveram suas coroas seccionadas para formar raízes com 15 mm de comprimento. Todos os dentes receberam tratamento endodôntico e em seguida foram divididos em 6 grupos (n=8), para receber a cimentação de acordo com o tipo de pino de fibra de vidro (opaco vs translúcido) e com o tempo de fotoativação do cimento resinoso (20, 40 e 60 segundos). Após o armazenamento em água a 37o C por uma semana, os dentes foram embutidos em resina acrílica e seccionados perpendicularmente ao seu longo eixo para formar discos de 1 mm de espessura, sendo 2 discos para cada terço radicular, e em seguida foram levados à máquina de ensaios universal. O teste de push-out foi realizado a uma velocidade de 0,5 mm/min. Os dados obtidos foram analisados estatisticamente por meio do teste ANOVA e pós-teste de Tukey (p=0,05). Os valores médios de RU (MPa) e desvio padrão (DP) para os grupos nos terços cervical, médio e apical foram respectivamente: PO20 – 21,02 ± 3,52, 15,83 ± 4,94 e 10,48 ± 5,20; PO40 – 14,42 ± 3,98, 12,12 ± 4,40 e 11,59 ± 4,89; PO60 – 16,27 ± 7,14, 13,33 ± 5,22 e 16,99 ± 7,82; PT20 – 18,34 ± 5,47, 10,83 ± 4,63 e 9,98 ± 4,76; PT40 – 17,51 ± 6,55, 14,06 ± 3,85 e 10,95 ± 4,65; PT60 – 19,42 ± 5,86, 15,35 ± 5,43 e 12,77 ± 5,93. Não foram observadas diferenças significativas entre os tipos de pino de fibra utilizados e os diferentes tempos de fotoativação (p > 0,05); em relação à região radicular foram encontradas diferenças estatisticamente significativas somente entre o terço cervical e os demais terços (p > 0,05). Pode-se concluir que a resistência de união do canal radicular não foi afetada pelo tipo de pino de fibra de vidro (opaco vs translúcido) e tempo de fotoativação.

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