Validation of DOE Factorial/Taguchi/Surface Response Models of Mechanical Properties of Synthetic and Natural Fiber Reinforced Epoxy Matrix Hybrid Material.

A validation of the factorial, Taguchi and response surface methodology (RSM) statistical models is developed for the analysis of mechanical tests of hybrid materials, with an epoxy matrix reinforced with natural Chambira fiber and synthetic fibers of glass, carbon and Kevlar. These materials present variability in their properties, so for the validation of the models a research methodology with a quantitative approach based on the statistical process of the design of experiments (DOE) was adopted; for which the sampling is in relation to the design matrix using 90 treatments with three replicates for each of the study variables. The analysis of the models reveals that the greatest pressure is obtained by considering only the source elements that are significant; this is reflected in the increase in the coefficient of determination and in the predictive capacity. The modified factorial model is best suited for the research, since it has an R2 higher than 90% in almost all the evaluated mechanical properties of the material; with respect to the combined optimization of the variables, the model showed an overall contribution of 99.73% and global desirability of 0.7537. These results highlight the effectiveness of the modified factorial model in the analysis of hybrid materials.

Análise mecânica comparativa do destorque de parafusos de minipilar com um novo componente protético, juntamente com avaliação microbiológica do vedamento para implantes de plataforma Cone Morse / Comparative mechanical analysis of the untorsion of miniabutment screws with a new prosthetic component, together with microbiological evaluation of the seal for Cone Morse platform implants

A interface implante pilar (IAI) por se constituir de duas peças inevitavelmente apresentam micro lacuna (GAP), na qual pode ocorrer infiltração bacteriana, permitindo a penetração de microorganismos que colonizam na parte interna do implante levando ao acúmulo de biofilme e, podendo levar ao desenvolvimento da periimplantite. O desgaste da conexão interna do implante é algo que ocorre com frequência, muitas vezes pela fratura do parafuso e/ou, pela perda da rosca interna do implante. A ausência de informações prévias também pode gerar a necessidade da remoção do implante, devido a estas intercorrências, surge a possibilidade da criação de um novo componente para implantes para possibilitar a reabilitação protética, sem ter que passar por uma nova cirurgia de remoção e instalação do implante. O objetivo do trabalho foi mensurar o nível de afrouxamento do parafuso do pilar protético e do minipilar comparando com novo componente protéticos, na tentativa de simular o comportamento do conjunto implante/pilar/prótese. Foram utilizados vinte implantes de plataforma cone morse (CM) da DSP® com seus respectivos mini pilares, na qual foram distribuídos em 2 grupos(n=10): Grupo 1 - implante CM + mini pilar FlexCone® DSP + coroa simplificada pirâmide invertida carga aplicada 3 mm do centro da coroa. E Grupo 2 - implante CM + mini pilar novo + coroa simplificada pirâmide invertida carga aplicada 3 mm do centro da coroa. Foram realizados ciclagem mecânica com carga 133 N, durante 2x106 ciclos, com frequência 2 Hz e temperatura de 37ºC em ambos grupos. Um torquímetro digital foi usado para medir os valores de torque reverso do parafuso protético da coroa e também do pilar protético, antes e após o carregamento. Os resultados do modelo de regressão demonstraram diferenças estatisticamente significativas em função do envelhecimento comparando os grupos da coroa sobre o pilar protético (p = 0.020) e entre os grupos do pilar sobre o implante (p = 0.048), indicando que após o envelhecimento de 2.000.000 de ciclos ao longo do tempo está associado de maneira significativa a essas variáveis no contexto deste estudo. O segundo objetivo deste estudo foi avaliar in vitro a taxa de infiltração bacteriana através da IAI, entre o novo componente protético e a superfície interna do implante, juntamente foi analisado a permeabilidade do IAI para colonização bacteriana. Um total de oitenta implantes foram testados. As estruturas montadas para grupo 1 foi torqueado com 20 N/cm e do G2 foram torqueados com 45 N, ambos imersos em microtubos contendo 200 µl de saliva humana. Após 14 dias de incubação da amostra de bactéria nos implantes, foi realizada uma análise qPCR (reação da cadeia da polimerase em tempo real). O teste revelou que não houve diferenças estatisticamente significativas no crescimento bacteriana entre os grupos em qualquer um dos pontos temporais analisados. Conclui-se que o novo componente testado apresentou um destoque menor do que comparado ao mini pilar FlexCone DSP® e apresentou infiltração bacteriana no GAP da conexão implante-pilar semelhante comparado ao mini pilar original da empresa (AU)

The abutment implant interface (IAI), as it consists of two pieces, inevitably presents a micro gap (GAP), in which bacterial infiltration can occur, allowing the penetration of microorganisms that colonize in the internal part of the implant, leading to the accumulation of biofilm and, which can lead to development of peri-implantitis. Wear of the implant's internal connection is something that occurs frequently, often due to screw fracture and/or loss of the implant's internal thread. The lack of prior information can also generate the need to remove the implant, due to these complications, the possibility arises of creating a new component for implants to enable prosthetic rehabilitation, without having to undergo a new surgery to remove and install the implant. implant. The objective of the work was to measure the level of screw loosening of the prosthetic abutment and the mini-abutment compared with the new prosthetic component, in an attempt to simulate the behavior of the implant/ abutment/prosthesis set. Twenty DSP® morse cone (CM) platform implants were used with their respective mini pillars, which were distributed into 2 groups (n=10): Group 1 - CM implant + FlexCone® DSP mini pillar + simplified crown inverted pyramid load applied 3 mm from the center of the crown. And Group 2 - CM implant + new mini abutment + simplified crown inverted pyramid load applied 3 mm from the center of the crown. Mechanical cycling was carried out with a load of 133 N, for 2x106 cycles, with a frequency of 2 Hz and a temperature of 37ºC in both groups. A digital torque wrench was used to measure the reverse torque values of the prosthetic crown screw and also the prosthetic abutment, before and after loading. The results of the regression model demonstrated statistically significant differences as a function of aging comparing the crown-on-prosthetic abutment groups (p =0.020) and between the abutment-on-implant groups (p = 0.048), indicating that after aging 2,000 ,000 cycles over time is significantly associated with these variables in the context of this study. The second objective of this study was to evaluate in vitro the rate of bacterial infiltration through the IAI, between the new prosthetic component and the internal surface of the implant, together with the permeability of the IAI for bacterial colonization. A total of eighty implants were tested. The assembled structures for group 1 were torqued with 20 N/cm and G2 were torqued with 45 N, both immersed in microtubes containing 200 µl of human saliva. After 14 days of incubation of the bacteria sample in the implants, a qPCR (real-time polymerase chain reaction) analysis was performed. The test revealed that there were no statistically significant differences in bacterial growth between groups at any of the time points analyzed. It is concluded that the new component tested presented a lower impact compared to the FlexCone DSP® mini abutment and presented bacterial infiltration in the GAP of the implant-abutment connection similar to the company's original mini abutment.(AU)

Biopolymer Non-Parametric Analysis: A Degradation Study under Accelerated Destructive Tests.

The degradation of biopolymers such as polylactic acid (PLA) has been studied for several years; however, the results regarding the mechanism of degradation are not completely understood yet. PLA is easily processed by traditional techniques including injection molding, blow molding, extrusion, and thermoforming; in this research, the extrusion and injection molding processes were used to produce PLA samples for accelerated destructive testing. The methodology employed consisted of carrying out material testing under the guidelines of several ASTM standards; this research hypothesized that the effects of UV light, humidity, and temperature exposure have a statistical difference in the PLA degradation rate. The multivariate analysis of non-parametric data is presented as an alternative to multivariate analysis, in which the data do not satisfy the essential assumptions of a regular MANOVA, such as multivariate normality. A package in the R software that allows the user to perform a non-parametric multivariate analysis when necessary was used. This paper presents a study to determine if there is a significant difference in the degradation rate after 2000 h of accelerated degradation of a biopolymer using the multivariate and non-parametric analyses of variance. The combination of the statistical techniques, multivariate analysis of variance and repeated measures, provided information for a better understanding of the degradation path of the biopolymer.

Triacrylamide-Based Adhesives Stabilize Bonds in Physiologic Conditions.

In this study, an acrylamide-based adhesive was combined with a thiourethane-based composite to improve bond stability and reduce polymerization stress, respectively, of simulated composite restorations. The stability testing was conducted under physiologic conditions, combining mechanical and bacterial challenges. Urethane dimethacrylate was combined with a newly synthesized triacrylamide (TMAAEA) or HEMA (2-hydroxyethyl-methacrylate; control) to produce a 2-step total-etch adhesive system. Methacrylate-based composites (70 wt% silanized filler) were formulated, containing thiourethane oligomers at 0 (control) or 20 wt%. Standardized preparations in human third molars were restored; then, epoxy replicas were obtained from the occlusal surfaces before and after 7-d storage in water or with Streptococcus mutans biofilm, which was tested after storage in an incubator (static) or the bioreactor (mechanical challenge). Images were obtained from the replicas (scanning electron microscopy) and cross sections of the samples (confocal laser scanning microscopy) and then analyzed to obtain measurements of gap, bacterial infiltration, and demineralization. Microtensile bond strength of specimens stored in water or biofilm was assessed in 1-mm2 stick specimens. Data were analyzed with analysis of variance and Tukey's test (α = 0.05). HEMA-based materials had greater initial gap measurements, indicating more efficient bonding for the acrylamide materials. When tested in water, the triacrylamide-based adhesive had smaller gaps in the incubator or bioreactor. In the presence of biofilm, there was less difference among materials, but the acrylamide/thiourethane combination led to statistically lower gap formation in the bioreactor. HEMA and TMAAEA-based adhesives produced statistically similar microtensile bond strengths after being stored in water for 7 d, but after the same period with biofilm-challenged specimens, the TMAAEA-based adhesives were the only ones to retain the initial bond strength values. The use of a stable multiacrylamide-based adhesive led to the preservation of the resin-dentin bonded interface after a physiologically relevant challenge. Future studies will include a multispecies biofilm model.

A new composite made from Luffa Cylindrica and ethylene vinyl acetate (EVA): Mechanical and structural characterization for its use as Mouthguard (MG).

The use of Mouthguards (MGs) in contact sports is an interesting biomedical topic. MGs are protective personal equipment made principally from the copolymer ethylene vinyl acetate (EVA). EVA is a thermoplastic whose thickness and rigidity are variables of concern for a good shock energy absorption capability in an MG. A natural fiber polymer composite is an interesting attempt for tackling these variables. Luffa cylindrica (luffa) is a sponge gourd that grows in 3D structure, which is used mainly as an ornament, a filling, or is trimmed for its use as a bathing product. In this work, a new EVA-luffa composite (EVLc) was made from commercial EVA sheets and luffa mat acting as reinforcement. FTIR, DSC, and TGA tests of EVA revealed its nature compared to literature data. A mechanical testing was applied to eight EVLc ASTM D-638 type V dumbbells (D1-D8) that showed low tensile strength values compared to EVA resistance ranges in literature. SEM images of EVLc's D1-D8 confirmed good adhesion between the reinforcement and matrix without surface treatment, and a descriptive statistical analysis indicated an intrinsic variation.

Response of composite resins to preheating and the resulting strengthening of luted feldspar ceramic.

OBJECTIVE: This study evaluated the influence of preheating different composite resins on their viscosity and strengthening yielded to ceramic. METHODS: Modulus of elasticity, Poisson's ratio, and degree of CC conversion were measured for three restorative composite resins (Z100-microhybrid; Empress Direct-nanohybrid; Estelite Omega-supranano) and one photoactivated resin cement (RelyX Veneer). Viscosity was measured during a heating-cooling curve (25°C-69°C-25°C) and also using isothermal analyses at 25°C and 69°C. Feldspar ceramic disks simulating veneers were bonded with the luting materials. Biaxial flexural strength, characteristic strength, and Weibull modulus were calculated at axial positions (z=0 and z=-t2) of the bilayers. Film thickness was measured and morphology at the bonded interfaces was observed. Data were statistically analyzed (α=0.05). RESULTS: A gradual decrease in viscosity was noticed as the rheometer temperature gradually increased. Viscosity differences between the composite resins were large at the beginning of the analysis, but minor at 69°C. At 25°C, the composites were up to 38 times more viscous than the resin cement; at 69°C the difference was 5-fold. CC conversion was similar between all resin-based agents. The resin cement yielded lower film thickness than the composites. All resin-based agents were able to infiltrate the ceramic porosities at the interface and strengthen the ceramic. However, the magnitude of the strengthening effect was higher for the preheated composite resins, particularly at z=-t2. SIGNIFICANCE: Selection of composite resin impacts its response to preheating and the resulting viscosity, film thickness, and magnitude of ceramic strengthening.

An in vitro investigation and comparison of the mechanical properties of human amnion and bovine collagen membrane

Introduction: The human amnion membrane is now increasingly used in Guided Tissue Regeneration(GTR). These placental allografts have excellent biologic properties. There is limited information regarding their mechanical properties as compared to other collagen membranes used in GTR. The aim of this study was to test and compare the mechanical properties of human amnion membrane with commercially available bovine collagen. Materials and methods: After measurement of average thickness, three strips of 5×1cm were cut from both amnion and bovine collagen membranes. Mechanical testing was done in a universal testing machine. Test speed was 1mm/min with a load cell of 100N. Tensile strength, Young's modulus and elongation at break were calculated. A suture retention test was also carried out using 3x1 cm size strips. Groups were compared through the Mann-Whitney U test. Results: Average thickness of amnion membrane was 0.46mm and thickness of bovine collagen membrane was 0.37mm.Tensile strength, Young's modulus and elongation at break of amnion membrane were 0.156MPa, 0.645MPa and 17mm; and that of bovine collagen membrane were 2.94MPa, 7.42MPa and 11.00mm, respectively (p = 0.05). Maximum load which can be applied during suturing for amnion membrane was 0.104N and for bovine collagen membrane was 2.07N (p = 0.037). Conclusion: There is no statistically significant difference in terms of tensile strength, Young's modulus and elongation at break between human amnion and bovine collagen membranes.(p=0.05)Membranes can only be considered different on the maximum load which can be applied during suturing.(p=0.037) (AU)

Efeito de regimes de treinamento físico de alto impacto nas propriedades mecânicas de ossos: estudo experimental em ratas wistar / Effects of high-impact exercise training on bone mechanical proprieties: an experimental study in female wistar rats

INTRODUÇÃO: A realização de atividade física garante benefícios ao tecido ósseo uma vez que o estresse provocado pelo carregamento promove adaptações positivas em suas propriedades mecânicas, sendo sua utilização uma estratégia não farmacológica para fortalecimento ósseo. OBJETIVO: investigar o efeito de protocolos de treinamento de alto impacto com frequências semanais e períodos diferentes nas propriedades mecânicas de ossos de ratas Wistar. MÉTODOS: Foram utilizadas 54 ratas Wistar, idade média de 10 semanas, divididas em seis grupos (n = 9): GCI (grupo controle, quatro semanas, sedentário), GTI3 (treinou três vezes por semana durante quatro semanas), GTI5 (treinou cinco vezes por semana, quatro semanas), GCII (grupo controle, oito semanas, sedentário), GTII3 (treinou três vezes por semana, oito semanas) e GTII5 (treinou cinco vezes por semana, oito semanas). O protocolo de alto impacto consistiu de 10 saltos verticais por sessão. RESULTADOS: Os ossos dos animais que receberam treinamento de alto impacto com frequência semanal elevada por um período maior de tempo mostraram valores superiores de suas propriedades mecânicas força máxima e rigidez relativa quando comparados aos demais grupos. CONCLUSÃO: Os resultados indicam que a realização de um protocolo de treinamento de alto impacto na forma de saltos verticais possui efeitos positivos sobre o tecido ósseo mesmo com frequência semanal reduzida, embora a realização de uma frequência semanal maior por um período mais elevado garanta melhores resultados.

INTRODUCTION: Physical activity has well established benefits on bone mechanical proprieties and is a non-pharmacological treatment strategy of bone weakening pathologies where given loading stress promotes adaptive responses that enhance bone strengthening. OBJECTIVE: to investigate the effect of high-impact exercise training protocols with different durations and weekly frequencies on bone mechanical proprieties of female Wistar rats. METHODS: fifty-four female Wistar rats, 10 weeks old, were divided into six groups (n=9 each): GCI (four week sedentary group, control), GTI3 (trained three times per week, four weeks), GTI5 (trained five times per week, four weeks), GCII (eight week sedentary group, control), GTII3 (trained three times per week, eight weeks) and GTII5 (trained five times per week, eight weeks). The high-impact training protocol was based on the completion of 10 vertical jumps by the animals per session. RESULTS: Bone mechanical proprieties in the groups that trained with higher weekly frequency for longer periods had greater maximum strength and stiffness when compared with the animals that trained less. CONCLUSIONS: the present results indicate that performance of high-impact training protocol has beneficial effects on bone mechanical proprieties, even with low weekly frequency, suggesting hence, that for bone gain, daily work volume is not necessary; however, for greater result, daily exercise does present better outcome.

Mecânica e microbiologia de placas produzidas a partir de osso cortical bovino, conservadas em diferentes meios / Mechanic and microbiology of plates produced from bovine cortical bone, conserved in several means

Objetivou-se com este trabalho avaliar a resistência mecânica de placas ósseas produzidas a partir de osso cortical bovino, conservadas em diferentes meios, e a eficiência desses meios em inibir o crescimento de microrganismos. Foram utilizadas 168 placas confeccionadas a partir de tíbia bovina e conservadas em glicerina a 98 por cento, solução salina a 150 por cento, solução de açúcar a 300 por cento, líquido de Dakin, congeladas em N2L a -196°C, ou esterilizadas em óxido de etileno. Após reidratação em solução de cloreto de sódio a 0,9 por cento por seis horas, elas foram submetidas a ensaios mecânicos de tração, compressão, flexão e torção. Foi realizada avaliação microbiológica das placas anterior e imediatamente após a reidratação, com ou sem adição de enrofloxacina a 0,5 por cento. Não se observou diferença significativa (P<0,01 por cento) da resistência ao ponto de ruptura entre as placas conservadas nos diferentes meios, congeladas-descongeladas ou esterilizadas. Micro-organismos foram isolados das placas conservadas em solução saturada de sal, açúcar, Dakin ou congeladas em N2L, anterior e após a reidratação. Entretanto, após o uso da solução de cloreto de sódio 0,9 por cento, acrescida de enrofloxacina a 0,5 por cento, não foram isolados microrganismos. Portanto, placas de osso bovino, conservadas em solução saturada de açúcar ou sal, glicerina a 98 por cento, solução de Dakin, congeladas em N2L ou esterilizadas em óxido de etileno assemelham-se em relação à biomecânica e a reidratação com solução de cloreto de sódio a 0,9 por cento, acrescida de enrofloxacina a 0,5 por cento, é eficaz no controle do crescimento microbiano.

The objective of this study was to evaluate the mechanical strength of bone plates yielded from bovine cortical bone, conserved in different solutions, and the efficiency of these solutions in the inhibition of microorganism's growth. A hundred and sixty eight plates yielded from bovine tibiae were conserved in 98 percent glycerin, 150 percent saline solution, 300 percent sugar solution, Dakin solution, frozen in N2L at - 196°C, or sterilized in ethylene oxide gas. After rehydration in NaCl 0.9 percent solution for six hours, plates were subjected to tensile, compression, bending and twisting testing. The microbiological evaluation of bone plates was s carried out before and immediately after rehydration, with or without enrofloxacin 0.5 percent addition. There was no significant difference (P<0.01 percent) on resistance to the rupture point in plates conserved in different solutions, frozen-thawed or sterilized. Microorganisms were isolated from plates conserved in satured salt solution, sugar satured solution, Dakin solution or frozen in N2L, before and after rehydraion However, after the use of NaCl 0.9 percent solution added of enrofloxacin 0.5 percent, microorganisms were not isolated. Therefore, bovine bone plates conserved in sugar or salt satured solution, 98 percent glycerin, Dakin solution, frozen in N2L or sterilized in ethylene oxide gas present similar biomechanical tests results, and rehydrated with a solution of NaCl 0.9 percent plus enrofloxacin 0.5 percent is effective on microorganism growth control.

Mecânica e microbiologia de placas produzidas a partir de osso cortical bovino, conservadas em diferentes meios

The objective of this study was to evaluate the mechanical strength of bone plates yielded from bovine cortical bone, conserved in different solutions, and the efficiency of these solutions in the inhibition of microorganism's growth. A hundred and sixty eight plates yielded from bovine tibiae were conserved in 98% glycerin, 150% saline solution, 300% sugar solution, Dakin solution, frozen in N2L at - 196°C, or sterilized in ethylene oxide gas. After rehydration in NaCl 0.9% solution for six hours, plates were subjected to tensile, compression, bending and twisting testing. The microbiological evaluation of bone plates was s carried out before and immediately after rehydration, with or without enrofloxacin 0.5% addition. There was no significant difference (P 0.01%) on resistance to the rupture point in plates conserved in different solutions, frozen-thawed or sterilized. Microorganisms were isolated from plates conserved in satured salt solution, sugar satured solution, Dakin solution or frozen in N2L, before and after rehydraion However, after the use of NaCl 0.9% solution added of enrofloxacin 0.5%, microorganisms were not isolated. Therefore, bovine bone plates conserved in sugar or salt satured solution, 98% glycerin, Dakin solution, frozen in N2L or sterilized in ethylene oxide gas present similar biomechanical tests results, and rehydrated with a solution of NaCl 0.9% plus enrofloxacin 0.5% is effective on microorganism growth control.

Objetivou-se com este trabalho avaliar a resistência mecânica de placas ósseas produzidas a partir de osso cortical bovino, conservadas em diferentes meios, e a eficiência desses meios em inibir o crescimento de microrganismos. Foram utilizadas 168 placas confeccionadas a partir de tíbia bovina e conservadas em glicerina a 98%, solução salina a 150%, solução de açúcar a 300%, líquido de Dakin, congeladas em N2L a -196°C, ou esterilizadas em óxido de etileno. Após reidratação em solução de cloreto de sódio a 0,9% por seis horas, elas foram submetidas a ensaios mecânicos de tração, compressão, flexão e torção. Foi realizada avaliação microbiológica das placas anterior e imediatamente após a reidratação, com ou sem adição de enrofloxacina a 0,5%. Não se observou diferença significativa (P 0,01%) da resistência ao ponto de ruptura entre as placas conservadas nos diferentes meios, congeladas-descongeladas ou esterilizadas. Micro-organismos foram isolados das placas conservadas em solução saturada de sal, açúcar, Dakin ou congeladas em N2L, anterior e após a reidratação. Entretanto, após o uso da solução de cloreto de sódio 0,9%, acrescida de enrofloxacina a 0,5%, não foram isolados microrganismos. Portanto, placas de osso bovino, conservadas em solução saturada de açúcar ou sal, glicerina a 98%, solução de Dakin, congeladas em N2L ou esterilizadas em óxido de etileno assemelham-se em relação à biomecânica e a reidratação com solução de cloreto de sódio a 0,9%, acrescida de enrofloxacina a 0,5%, é eficaz no controle do crescimento microbiano.

Mecânica e microbiologia de placas produzidas a partir de osso cortical bovino, conservadas em diferentes meios

The objective of this study was to evaluate the mechanical strength of bone plates yielded from bovine cortical bone, conserved in different solutions, and the efficiency of these solutions in the inhibition of microorganism's growth. A hundred and sixty eight plates yielded from bovine tibiae were conserved in 98% glycerin, 150% saline solution, 300% sugar solution, Dakin solution, frozen in N2L at - 196°C, or sterilized in ethylene oxide gas. After rehydration in NaCl 0.9% solution for six hours, plates were subjected to tensile, compression, bending and twisting testing. The microbiological evaluation of bone plates was s carried out before and immediately after rehydration, with or without enrofloxacin 0.5% addition. There was no significant difference (P 0.01%) on resistance to the rupture point in plates conserved in different solutions, frozen-thawed or sterilized. Microorganisms were isolated from plates conserved in satured salt solution, sugar satured solution, Dakin solution or frozen in N2L, before and after rehydraion However, after the use of NaCl 0.9% solution added of enrofloxacin 0.5%, microorganisms were not isolated. Therefore, bovine bone plates conserved in sugar or salt satured solution, 98% glycerin, Dakin solution, frozen in N2L or sterilized in ethylene oxide gas present similar biomechanical tests results, and rehydrated with a solution of NaCl 0.9% plus enrofloxacin 0.5% is effective on microorganism growth control.

Objetivou-se com este trabalho avaliar a resistência mecânica de placas ósseas produzidas a partir de osso cortical bovino, conservadas em diferentes meios, e a eficiência desses meios em inibir o crescimento de microrganismos. Foram utilizadas 168 placas confeccionadas a partir de tíbia bovina e conservadas em glicerina a 98%, solução salina a 150%, solução de açúcar a 300%, líquido de Dakin, congeladas em N2L a -196°C, ou esterilizadas em óxido de etileno. Após reidratação em solução de cloreto de sódio a 0,9% por seis horas, elas foram submetidas a ensaios mecânicos de tração, compressão, flexão e torção. Foi realizada avaliação microbiológica das placas anterior e imediatamente após a reidratação, com ou sem adição de enrofloxacina a 0,5%. Não se observou diferença significativa (P 0,01%) da resistência ao ponto de ruptura entre as placas conservadas nos diferentes meios, congeladas-descongeladas ou esterilizadas. Micro-organismos foram isolados das placas conservadas em solução saturada de sal, açúcar, Dakin ou congeladas em N2L, anterior e após a reidratação. Entretanto, após o uso da solução de cloreto de sódio 0,9%, acrescida de enrofloxacina a 0,5%, não foram isolados microrganismos. Portanto, placas de osso bovino, conservadas em solução saturada de açúcar ou sal, glicerina a 98%, solução de Dakin, congeladas em N2L ou esterilizadas em óxido de etileno assemelham-se em relação à biomecânica e a reidratação com solução de cloreto de sódio a 0,9%, acrescida de enrofloxacina a 0,5%, é eficaz no controle do crescimento microbiano.

Retrieval analysis of motion preserving spinal devices and periprosthetic tissues.

This article reviews certain practical aspects of retrieval analysis for motion preserving spinal implants and periprosthetic tissues as an essential component of the overall revision strategy for these implants. At our institution, we established an international repository for motion-preserving spine implants in 2004. Our repository is currently open to all spine surgeons, and is intended to be inclusive of all cervical and lumbar implant designs such as artificial discs and posterior dynamic stabilization devices. Although a wide range of alternative materials is being investigated for nonfusion spine implants, many of the examples in this review are drawn from our existing repository of metal-on-polyethylene, metal-on-metal lumbar total disc replacements (TDRs), and polyurethane-based dynamic motion preservation devices. These devices are already approved or nearing approval for use in the United States, and hence are the most clinically relevant at the present time. This article summarizes the current literature on the retrieval analysis of these implants and concludes with recommendations for the development of new test methods that are based on the current state of knowledge of in vivo wear and damage mechanisms. Furthermore, the relevance and need to evaluate the surrounding tissue to obtain a complete understanding of the biological reaction to implant component corrosion and wear is reviewed.