Many bridges are destroyed or completely failed during floods due to excessive scouring around bridge piers and abutments. Safe bridge design is based on joint consideration of structural, hydraulic, and geotechnical aspects. This study is concerned with the investigation of various types of countermeasures against scouring at bridge sites. The design criteria for various countermeasures are reviewed in terms of hydraulic, hydrologic, constructional, and economical requirements. (Conditions of applicability of these countermeasures are evaluated and designed for different return periods of flow, and hydroeconomic analyses are performed for Esenbosa Bridge). Based on the evaluation of the results of hydroeconomic analyses, combinations of rock riprap and grout filled bags are found to be appropriate measures for piers and abutments against scouring whereas vegetation is observed to be applicable for bank protection.

Made available in DSpace on 2014-06-11T19:26:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2005Bitstream added on 2014-06-13T20:55:05Z : No. of bitstreams: 1 fujiwara_ca_me_araca.pdf: 1023210 bytes, checksum: d5bfe58a6ad917370b05a41403af9e6f (MD5) / Universidade Estadual Paulista (UNESP) / A adaptação entre a plataforma do implante e seu respectivo abutment deve ser precisa, isto é, sem nenhuma fenda, que é denominada microgap, entre as estruturas. A presença do microgap permite que microorganismos presentes na microbiota bucal migrem para o interior do implante, o que pode ocasionar problemas de natureza inflamatória e ou infecciosa, e, conseqüentemente, causar a perda do implante. Neste estudo utilizamos uma amostragem de 26 (vinte e seis) implantes e seus respectivos abutments provenientes de 5 (cinco) marcas comerciais diferentes: AS Tecnology, Conexão Sistema de Prótese, Neodent Implante Osteointegrado, Sterngold Implamed, e 3i Implant Innovation. Os abutments receberam um torque de 20Ncm. Os cortes longitudinais da interface implante/abutment foram mensurados em 6 (seis) locais com o auxílio da microscopia eletrônica de varredura. Os resultados das mensurações foram submetidos à análise estatística. Foi possível concluir que: 1) A seqüência dos grupos, em relação ao gap encontrado, do menor para o maior, foram: abutment cônico, abutment gold ucla, abutment mult unit. 2) O abutment cônico e o abutment mult unit apresentaram gaps menores que o abutment gold ucla. 3) O ponto interno apresentou gap menor em relação ao ponto médio, o qual foi menor que o ponto externo, portanto, as peças tenderam a convergir para o ponto interno. / The adaptation of the implant platform and its respective abutment must be precise, with no space denominated microgap, between the structures. The presence of a microgap allows microorganisms that are present in the buccal microbiology to migrate into the implant, what could cause inflammatory and/or infectious problems, and consequent loss of the implant. In this study, a sample of 26 (twenty six) implants and their respective abutments was taken: conic, multi unit, and the gold ucla - together with their respective fixing screws. The abutments received a manual torque of 20Ncm. After the manual preparation, the interface implant/abutment longitudinal cuts were measured on 6 (six) different points through an Scanning Electron Microscope (SEM). The results of such measurements were statistically analyzed, and according to the experimental conditions of this study, was possible to conclude: 1) The sequential groups of implants/abutments, in relation to the gap found, from the smaller to the biggest, were: a) conic abutment , b) gold ucla abutment , c) multi unit abutment. 2) The conic and the multi unit abutments showed smaller gaps than the gold ucla abutments. 3) The internal point showed a smaller gap than the middle point, and the middle point, in return, also showed a smaller gap in relation to the external point; therefore, the pieces tended to converge to the internal point.

Orientador: Osvaldo Magro Filho / Resumo: A adaptação entre a plataforma do implante e seu respectivo abutment deve ser precisa, isto é, sem nenhuma fenda, que é denominada microgap, entre as estruturas. A presença do microgap permite que microorganismos presentes na microbiota bucal migrem para o interior do implante, o que pode ocasionar problemas de natureza inflamatória e ou infecciosa, e, conseqüentemente, causar a perda do implante. Neste estudo utilizamos uma amostragem de 26 (vinte e seis) implantes e seus respectivos abutments provenientes de 5 (cinco) marcas comerciais diferentes: AS Tecnology, Conexão Sistema de Prótese, Neodent Implante Osteointegrado, Sterngold Implamed, e 3i Implant Innovation. Os abutments receberam um torque de 20Ncm. Os cortes longitudinais da interface implante/abutment foram mensurados em 6 (seis) locais com o auxílio da microscopia eletrônica de varredura. Os resultados das mensurações foram submetidos à análise estatística. Foi possível concluir que: 1) A seqüência dos grupos, em relação ao gap encontrado, do menor para o maior, foram: abutment cônico, abutment gold ucla, abutment mult unit. 2) O abutment cônico e o abutment mult unit apresentaram gaps menores que o abutment gold ucla. 3) O ponto interno apresentou gap menor em relação ao ponto médio, o qual foi menor que o ponto externo, portanto, as peças tenderam a convergir para o ponto interno. / Abstract: The adaptation of the implant platform and its respective abutment must be precise, with no space denominated microgap, between the structures. The presence of a microgap allows microorganisms that are present in the buccal microbiology to migrate into the implant, what could cause inflammatory and/or infectious problems, and consequent loss of the implant. In this study, a sample of 26 (twenty six) implants and their respective abutments was taken: conic, multi unit, and the gold ucla - together with their respective fixing screws. The abutments received a manual torque of 20Ncm. After the manual preparation, the interface implant/abutment longitudinal cuts were measured on 6 (six) different points through an Scanning Electron Microscope (SEM). The results of such measurements were statistically analyzed, and according to the experimental conditions of this study, was possible to conclude: 1) The sequential groups of implants/abutments, in relation to the gap found, from the smaller to the biggest, were: a) conic abutment , b) gold ucla abutment , c) multi unit abutment. 2) The conic and the multi unit abutments showed smaller gaps than the gold ucla abutments. 3) The internal point showed a smaller gap than the middle point, and the middle point, in return, also showed a smaller gap in relation to the external point; therefore, the pieces tended to converge to the internal point. / Mestre

Objetivo: Avaliar a interface pilar protético/implante e o destorque, quando utilizados parafusos recobertos com Diamond-like carbon (DLC) e parafusos convencionais de titânio para fixação dos componentes protéticos, antes e após ação de carga cíclica. Posteriormente, avaliar a correlação entre o desajuste vertical da interface pilar UCLAimplante e o destorque dos parafusos dos pilares. Método: Trinta e seis implantes foram divididos em quatro grupos de acordo com o tipo de conexão (hexágono externo e interno) e do parafuso utilizado para fixar o pilar ao implante (titânio ou recoberto com DLC), ou seja: Grupo A: hexágono externo/parafuso titânio; Grupo B: hexágono externo/parafuso recoberto com DLC; Grupo C: hexágono interno/parafuso titânio;Grupo D: hexágono interno/parafuso recoberto com DLC. Após os implantes terem sido incluídos em resina acrílica incolor, coroas foram enceradas sobre pilares UCLA, fundidas com liga metálica de Ni-Cr-Ti e parafusadas aos implantes com aplicação do torque recomendado pelo fabricante. Em seguida, as interfaces pilar/implante foram mensuradas, em microscópio de luz, em quatro pontos de cada amostra (DV1). Após as amostras terem sido submetidas a um milhão de ciclos mecânicos, as interfaces foram novamente mensuradas (DV2). Para comparar os valores médios, intra e intergrupos, das interfaces pilar/implante, da diferença entre os mesmos e os valores de destorque, os dados foram submetidos à Análise de Variância, ao teste t de Student e ao teste de Mann Whitney (p≤0,05). E para a correlação entre os fatores estudados, os resultados foram submetidos ao teste de correlação de Pearson (p≤0,05). Resultados: Os implantes com hexágono externo apresentaram os maiores valores de desajuste vertical pilar UCLA/implante antes (DV1) e após (DV2) ciclagem mecânica (GA/DV1 = 59,81μm e GA/DV2 = 62,59μm, GB/DV1 = 73,73μm e GB/DV2 = 72,95μm). Nos grupos onde foram utilizados parafusos de titânio foi observado aumento dos valores da interface pilar/implante de DV1 para DV2 (GA = de 59.81μm para 62.50μm e GC = de 18.13μm para 22.54μm). Nos grupos onde foram utilizados parafusos de DLC foi evidenciada redução dos valores da interface pilar/implante de DV1 para DV2 (GB = de 73.73μm para 72.95μm e GD = de 16.07μm para 14.47μm. Somente o GC apresentou diferença significativa entre os valores mensurados na interface pilar/implante antes e após o carregamento cíclico (p=0,05). Para correlacionar os valores de destorque aos valores das interfaces pilar/implante, foi aplicado o teste de correlação de Pearson, porém não foi verificada diferença significativa entre os fatores estudados (p˃0,05). Conclusões: As interfaces pilar UCLA/implante foram maiores nos grupos com hexágono externo que nos grupos com hexágono interno, porém sem diferença significativa quando utilizados parafusos de titânio ou revestidos com DLC. Houve perda de torque após carga cíclica em todos os grupos. Não é possível afirmar que um maior valor de interface pilar/implante esteja correlacionado com o desaperto do parafuso. / Purpose: To evaluate the interface abutment/implant, and the loosening screws values when used screws with Diamond-like carbon (DLC) coated and conventional titanium screws for fixation of prosthetic components, before and after action of cyclic loading. After, to evaluate the connections between the values of interface abutment UCLA/implant and loosening screw. Method: Thirty six implants were divided into four groups according to the type connection (external hexagon and internal hexagon) and screw used to fix the abutment to the implant (titanium or coated with DLC): Group A: external hexagon / titanium screw; Group B: external hexagon / DLC screw; Group C: internal hexagon / titanium screw; Group D: internal hexagon / DLC screw. After the implants were included in colorless acrylic resin, crowns were waxed using UCLA type abutment, casting with metal alloy of Ni-Cr-Ti and screwed to the implants using the torque recommended by the manufacturer. Then the interfaces pillar/implant were measured with light microscope in four pre-marked points (DV1). After the sets (implant, crown and screw) were subjected to one million mechanical cycles and the interfaces measured again (DV2). Analysis of Variance, Test t Student and test Mann Whitney (p≤0,05) were applied to compare the average to the interfaces abutment/implant intra and intergroup, the difference between the same and the loosening screws values. And to evaluate the correlated between the factors studying, the Pearsons correlation test (p≤0,05). Results: The implants with external hexagon exhibited the higher values of the vertical misfit pillar UCLA/implant before (DV1) and after (DV2) cyclic loading (GA/DV1 = 59,81μm e GA/DV2 = 62,59μm, GB/DV1 = 73,73μm e GB/DV2 = 72,95μm). In groups of titanium shows screws there was an increase in interface abutment/implant after cyclic loading (GA = 59,81μm to 62,50μm and GC = 18,13μm to 22,54μm) and in groups with DLC coated screws there was a reduction the values of interface abutment/implant (GB = 73,73μm to 72,95μm and GD = 16,07μm to 14,47μm). Only group C showed a statistically significant difference to the interface abutment/implant before and after cyclic loading (p = 0.05) exhibited mean values and differences between the interfaces pillar/implant. To correlate the values of loosening to the values of pillar interfaces/implant was applied the Pearsons correlation test, but there was no significance among the studied factors (p ˃ 0.05). Conclusions: The interfaces pillar UCLA/implant were higher in groups with external hexagon connection those in groups with internal hexagon, but without significant differences when use titanium screws or coated with DLC. Always screws loosed torque after cycling load. Is not possible to affirm that a higher value of interface abutment/implant be correlated with the loosening screw.

This study presents the behavior of a precast skewed integral abutment bridge (IAB) using the recently developed NEXT-F Beam section in particular. In order to understand the bridge response, a 3-dimensional finite element model of a bridge (Brimfield Bridge) was developed to examine the thermal effect on the response of the bridge structural components. Eighteen months of field monitoring including abutments displacements, abutment rotations, deck strains, and beam strains was conducted utilizing 136 strain gauges, 6 crackmeters, and 2 tiltmeters. The behavior of the NEXT beams during construction was examined by conducting hand calculation considering all factors that could affect strain readings captured by strain gauges embedded in the 6 beams. Parametric analysis and model validation were conducted considering the effect of soil conditions, distribution of thermal loads, and the coefficient of thermal expansion used for the analyses. Using the validated model, the effect pile orientation was investigated. All the results and illustration plots are presented in detail in this study. As a result of this study, the behavior of the NEXT beams during construction was explained. Long term behavior of the bridge was also explained using field data and FE model. Furthermore, it was concluded that the coefficient of thermal expansion of concrete and temperature variation along the bridge depth and transverse direction can have a significant effect on the strain readings and calculated response, respectively. Lastly, it was found that orienting piles with their web perpendicular on the bridge centerline or with their web perpendicular to the abutment centerline will result in small ratio of moment demand to moment capacity.

Magister Chirurgiae Dentium (MChD) / Dental implants have proven to be a success in the past decades, however the inevitable presence of microgaps at the implant abutment interface leading to microleakage is still a distressing concern. Microbial leakage can lead to peri-implant disease and bone loss and reduces implants' success rates. Measures to decrease the effect of the microgap were introduced; amongst them is the application of silicone sealing gels, such as GapSeal®.

Magister Chirurgiae Dentium (MChD) / Background: Lack of appropriate bone thickness is a common clinical limitation for tooth replacement, often requiring narrow implants, which have shown better results when combined with Morse taper connections. Little is known about the sealing of the abutment-implant interface of narrow implants with Morse taper connections against oral bacteria. Aims: To investigate the in vitro ability of four commercially available narrow diameter implant (< 3.5 mm) with Morse-taper type implant abutment connections to impede bacterial penetration of their implant abutment interface (IAI). Material and Methods: Four commercially available narrow implant systems with Morse taper connections were subjected to Streptococcus sanguinis cultures in vitro and evaluated for contamination and microgaps through Scanning Electron Microscopy (SEM). Results: Bacterial penetration of the IAI was observed in all systems (n=12), ranging from 65 to >300 CFU. There were no statistically significant differences in the average log CFU between the four implant groups (χ2= 5.244, P=0.155). Microgaps ranging from 5-10 μm were observed in all assemblies when analyzed under SEM, with no statistically significant differences between the different systems (P>0.05). Conclusions: Despite the advantages of Morse taper systems, the evaluated narrow diameter implants using this type of abutment geometry failed to provide bacterial sealing. The observed microgaps can form reservoirs and potentially lead to inflammation in the peri-implant tissues and micromovements.

No description available.

A proposta deste estudo foi avaliar o torque de afrouxamento de três tipos de parafusos de fixação de abutment. Foram formados seis grupos: grupos HE-TiS e HE-TiNS (implante e abutment de hexágono externo, parafuso de fixação de titânio, submetidos e não-submetidos ao ensaio), grupos HE-AuS e HE-Au NS (implante e abutment de hexágono externo, parafuso de fixação de ouro, submetidos e não-submetidos ao ensaio) e grupos HI-TiS e HI-TiNS (implante e abutment de hexágono interno, parafuso de fixação de titânio, submetidos e não-submetidos ao ensaio). Para a realização da ciclagem mecânica, foi desenvolvida uma máquina de ensaio cuja carga máxima aplicada foi de 120 N em sentido axial, com deslizamento de 0,3mm sobre a superfície oclusal da coroa e força de atrito de 28 N a uma freqüência de 60 ciclos por minuto , durante 500.000 ciclos. O torque de apertamento inicial dos parafusos de fixação foi de 32 Ncm e o de afrouxamento mensurado a cada 100.000 ciclos nos grupos submetidos ao ensaio de ciclagem mecânica e a cada 24 horas após o torque de apertamento nos grupos não-submetidos ao ensaio. Dentro das condições experimentais deste estudo, os resultados obtidos sugerem que: os valores de destorque dos parafusos de fixação foram menores em todos os grupos submetidos ao ensaio; o destorque foi estatisticamente menor para os parafusos de titânio quando comparados os grupos HE-TiS (15,56±1,38 Ncm – 48%) / HE-AuS (18,15±1,85 Ncm – 56%) e os grupos HE-TiNS (23,76±1,59 Ncm – 74%) / HE-AuNS (27,06±1,23 Ncm – 84,5%); o destorque dos parafusos de titânio também foi estatisticamente menor quando utilizados nos grupos HE-TiS (15,56±1,38 Ncm – 48%), comparados aos grupos HI-TiS (18,56±1,14 Ncm – 58%). / The purpose of this study was to evaluate the abutment screw loosening when either submitted or not to cyclic loading. Six groups were composed: HE-TiS and HE-TiNS (external hexagonal implant and abutment, titanium abutment screw, submitted and not subimitted to cyclic loading), HE-AuS and HE-Au NS (external hexagonal implant and abutment, gold abutment screw, submitted not submitted to ciclyc loading), HI-TiS and HI-TiNS (internal hexagonal implant and abutment, titanium abutment screw, submitted and not submitted to ciclyc loading). In order to perform the cyclic loading, it was developed a device wich applied the maximum load of 120 N in the axial direction, with a slip of 0,3 mm on the crown oclusal surface with friction force of 28 N. The frequency was 60 cycles per minute for a duty of 500,000 cycles. The abutment screw was tightened to 32 Ncm and the loosening torque was measured after every 100,000 cycles in the submitted groups and every 24 hours after the tightening torque in the not-submitted groups. Within the limitations of this study, the results suggest that the loosening torque values were statistically significant lower in all groups submitted to the cyclic loading; the loosening torque was statiscally lower for titanium screws when compared HE-TiS (15,56±1,38 Ncm – 48%) / HE-AuS (18,15±1,85 Ncm – 56%) groups and HE-TiNS (23,76±1,59 Ncm – 74%) / HE-AuNS (27,06±1,23 Ncm – 84,5%) groups; the loosenig torque was also lower for the titanium screws when used to in the groups HE-TiS (15,56±1,38 Ncm – 48%) compared to HI-TiS (18,56±1,14 Ncm – 58%).

A proposta deste estudo foi avaliar o torque de afrouxamento de três tipos de parafusos de fixação de abutment. Foram formados seis grupos: grupos HE-TiS e HE-TiNS (implante e abutment de hexágono externo, parafuso de fixação de titânio, submetidos e não-submetidos ao ensaio), grupos HE-AuS e HE-Au NS (implante e abutment de hexágono externo, parafuso de fixação de ouro, submetidos e não-submetidos ao ensaio) e grupos HI-TiS e HI-TiNS (implante e abutment de hexágono interno, parafuso de fixação de titânio, submetidos e não-submetidos ao ensaio). Para a realização da ciclagem mecânica, foi desenvolvida uma máquina de ensaio cuja carga máxima aplicada foi de 120 N em sentido axial, com deslizamento de 0,3mm sobre a superfície oclusal da coroa e força de atrito de 28 N a uma freqüência de 60 ciclos por minuto , durante 500.000 ciclos. O torque de apertamento inicial dos parafusos de fixação foi de 32 Ncm e o de afrouxamento mensurado a cada 100.000 ciclos nos grupos submetidos ao ensaio de ciclagem mecânica e a cada 24 horas após o torque de apertamento nos grupos não-submetidos ao ensaio. Dentro das condições experimentais deste estudo, os resultados obtidos sugerem que: os valores de destorque dos parafusos de fixação foram menores em todos os grupos submetidos ao ensaio; o destorque foi estatisticamente menor para os parafusos de titânio quando comparados os grupos HE-TiS (15,56±1,38 Ncm – 48%) / HE-AuS (18,15±1,85 Ncm – 56%) e os grupos HE-TiNS (23,76±1,59 Ncm – 74%) / HE-AuNS (27,06±1,23 Ncm – 84,5%); o destorque dos parafusos de titânio também foi estatisticamente menor quando utilizados nos grupos HE-TiS (15,56±1,38 Ncm – 48%), comparados aos grupos HI-TiS (18,56±1,14 Ncm – 58%). / The purpose of this study was to evaluate the abutment screw loosening when either submitted or not to cyclic loading. Six groups were composed: HE-TiS and HE-TiNS (external hexagonal implant and abutment, titanium abutment screw, submitted and not subimitted to cyclic loading), HE-AuS and HE-Au NS (external hexagonal implant and abutment, gold abutment screw, submitted not submitted to ciclyc loading), HI-TiS and HI-TiNS (internal hexagonal implant and abutment, titanium abutment screw, submitted and not submitted to ciclyc loading). In order to perform the cyclic loading, it was developed a device wich applied the maximum load of 120 N in the axial direction, with a slip of 0,3 mm on the crown oclusal surface with friction force of 28 N. The frequency was 60 cycles per minute for a duty of 500,000 cycles. The abutment screw was tightened to 32 Ncm and the loosening torque was measured after every 100,000 cycles in the submitted groups and every 24 hours after the tightening torque in the not-submitted groups. Within the limitations of this study, the results suggest that the loosening torque values were statistically significant lower in all groups submitted to the cyclic loading; the loosening torque was statiscally lower for titanium screws when compared HE-TiS (15,56±1,38 Ncm – 48%) / HE-AuS (18,15±1,85 Ncm – 56%) groups and HE-TiNS (23,76±1,59 Ncm – 74%) / HE-AuNS (27,06±1,23 Ncm – 84,5%) groups; the loosenig torque was also lower for the titanium screws when used to in the groups HE-TiS (15,56±1,38 Ncm – 48%) compared to HI-TiS (18,56±1,14 Ncm – 58%).