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Francesco Clavica - One of the best experts on this subject based on the ideXlab platform.
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investigating the flow dynamics in the obstructed and stented ureter by means of a biomimetic Artificial Model
PLOS ONE, 2014Co-Authors: Francesco Clavica, Xuefeng Zhao, Motaz Elmahdy, Marcus J Drake, Xunli Zhang, Dario CarugoAbstract:Double-J stenting is the most common clinical method employed to restore the upper urinary tract drainage, in the presence of a ureteric obstruction. After implant, stents provide an immediate pain relief by decreasing the pressure in the renal pelvis (P). However, their long-term usage can cause infections and encrustations, due to bacterial colonization and crystal deposition on the stent surface, respectively. The performance of double-J stents - and in general of all ureteric stents - is thought to depend significantly on urine flow field within the stented ureter. However very little fundamental research about the role played by fluid dynamic parameters on stent functionality has been conducted so far. These parameters are often difficult to assess in-vivo, requiring the implementation of laborious and expensive experimental protocols. The aim of the present work was therefore to develop an Artificial Model of the ureter (i.e. ureter Model, UM) to mimic the fluid dynamic environment in a stented ureter. The UM was designed to reflect the geometry of pig ureters, and to investigate the values of fluid dynamic viscosity (μ), volumetric flow rate (Q) and severity of ureteric obstruction (OB%) which may cause critical pressures in the renal pelvis. The distributed obstruction derived by the sole stent insertion was also quantified. In addition, flow visualisation experiments and computational simulations were performed in order to further characterise the flow field in the UM. Unique characteristics of the flow dynamics in the obstructed and stented ureter have been revealed with using the developed UM.
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EMBC - An Artificial Model for studying fluid dynamics in the obstructed and stented ureter
2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2013Co-Authors: Dario Carugo, Xuefeng Zhao, Motaz Elmahdy, Marcus J Drake, Xunli Zhang, Francesco ClavicaAbstract:Fluid dynamics in the obstructed and stented ureter represents a non-trivial subject of investigation since, after stent placement, the urine can flow either through the stent lumen or in the extra-luminal space located between the stent wall and the ureteric inner wall. Fluid dynamic investigations can help understanding the phenomena behind stent failure (e.g. stent occlusions due to bacterial colonization and encrustations), which may cause kidney damage due to the associated high pressures generated in the renal pelvis. In this work a microfluidic-based transparent device (ureter Model, UM) has been developed to simulate the fluid dynamic environment in a stented ureter. UM geometry has been designed from measurements on pig ureters. Pressure in the renal pelvis compartment has been measured against three variables: fluid viscosity (μ), volumetric flow rate (Q) and level of obstruction (OB%). The measurements allowed a quantification of the critical combination of μ, Q and OB% values which may lead to critical pressure levels in the kidney. Moreover, an example showing the possibility of applying particle image velocimetry (PIV) technology to the developed microfluidic device is provided.
Anselm Petschelt - One of the best experts on this subject based on the ideXlab platform.
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influence of adhesive point dimension and splint type on splint rigidity evaluation by the dynamic periotest method
Dental Traumatology, 2013Co-Authors: Florian Franz, Sergej Potapov, Anselm Petschelt, Christine BertholdAbstract:Aim To evaluate the influence of adhesive point dimension and splint type on the rigidity of wire-composite splints in vitro. Materials and Methods A custom-made Artificial Model was used. The two central incisors served as injured teeth (degrees of loosening III and II) and the two lateral incisors as non-injured teeth (physiological mobility). Horizontal and vertical tooth mobilities were investigated before and after splinting with the Periotest® method; the percent change was taken as the relative splint effect. Teeth were splinted with three types of wire-composite splints: Dentaflex (0.45 mm), Strengtheners (0.8 × 1.8 mm), and Dentaflex completely covered with composite. Four adhesive point dimensions (2, 3, 4, and 5 mm) were evaluated. Normal distribution was tested with the Kolmogorov–Smirnov test. Differences were evaluated with the anova and post hoc tests for pair-wise comparisons. Significance level was set at 0.05. Results The adhesive point dimension did not influence splint rigidity, in general ( P = 0.288). Significant effects were found in non-injured teeth with the Dentaflex ( P < 0.001) and in injured teeth with the Strengtheners ( P < 0.001). The Strengtheners splint rigidity increased significantly with increasing adhesive point dimensions. The three splints showed significantly different effects at 5-mm adhesive point dimension ( P < 0.001). Conclusion Splint rigidity for injured teeth was influenced by adhesive point dimension only when splinting with Strengtheners. We recommend adapting splint rigidity by selecting different wires and reducing the adhesive point dimension to a minimum. Dentaflex can be used for flexible splinting, Strengtheners, and composite covered Dentaflex for rigid splinting.
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Influence of adhesive point dimension and splint type on splint rigidity – Evaluation by the dynamic Periotest method
Dental Traumatology, 2012Co-Authors: Florian Franz, Sergej Potapov, Anselm Petschelt, Christine BertholdAbstract:Aim To evaluate the influence of adhesive point dimension and splint type on the rigidity of wire-composite splints in vitro. Materials and Methods A custom-made Artificial Model was used. The two central incisors served as injured teeth (degrees of loosening III and II) and the two lateral incisors as non-injured teeth (physiological mobility). Horizontal and vertical tooth mobilities were investigated before and after splinting with the Periotest® method; the percent change was taken as the relative splint effect. Teeth were splinted with three types of wire-composite splints: Dentaflex (0.45 mm), Strengtheners (0.8 × 1.8 mm), and Dentaflex completely covered with composite. Four adhesive point dimensions (2, 3, 4, and 5 mm) were evaluated. Normal distribution was tested with the Kolmogorov–Smirnov test. Differences were evaluated with the anova and post hoc tests for pair-wise comparisons. Significance level was set at 0.05. Results The adhesive point dimension did not influence splint rigidity, in general ( P = 0.288). Significant effects were found in non-injured teeth with the Dentaflex ( P
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influence of wire extension and type on splint rigidity evaluation by a dynamic and a static measuring method
Dental Traumatology, 2011Co-Authors: Christine Berthold, Friedrich Johannes Auer, Sergej Potapov, Anselm PetscheltAbstract:Objectives To evaluate the influence of wire dimension and wire length on the splint rigidity of wire-composite splints in vitro. Materials and methods A custom-made Artificial Model was used. The central incisors simulated 'injured' teeth with increased mobility, and the lateral incisors and canines served as 'uninjured' teeth with physiological mobility. To assess horizontal and vertical tooth mobility before and after splinting, the Periotest and Zwick methods were applied. Teeth 13-23 were splinted using wire-composite splint 1 (WCS1; Dentaflex 0.45 mm) and wire-composite splint 2 (WCS2; Strengtheners 0.8 × 1.8 mm). Splint length was varied by successively shortening the wire. The influence of wire dimension was tested using t-test and Wilcoxon-Mann-Whitney test with the Bonferroni-Holm procedure (α = 0.05). To test the influence of wire length, anova and Kruskal-Wallis tests as well as Tukey range and Wilcoxon test with Bonferroni-Holm procedure were applied (α = 0.05). Results Wire dimension significantly influenced splint rigidity (P 0.05). Conclusion WCS1 is flexible compared with the more rigid WCS2. The wire length influences the rigidity. To ensure adequate fixation and reduce the risk of enamel damage during splint removal, the splint should include only one 'uninjured' tooth bilaterally.
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in vitro splint rigidity evaluation comparison of a dynamic and a static measuring method
Dental Traumatology, 2011Co-Authors: Christine Berthold, Friedrich Johannes Auer, Sergej Potapov, Anselm PetscheltAbstract:– Objectives: The aim of this in vitro study was to investigate a dynamic and static tooth mobility assessment method in terms of reproducibility and correlation. Materials and Methods: A custom-made Artificial Model was used. The central incisors simulated ‘injured’ teeth with increased mobility, and the lateral incisors served as ‘uninjured’ teeth with physiological mobility. To assess tooth mobility, three consecutively repeated measurements were taken, in the vertical and horizontal dimensions before and after splinting, using the Periotest method as well as the Zwick universal testing machine. Reproducibility of the measurements was tested using anova and the Bonferroni post hoc test (α = 0.05). Correlation was analysed using Spearman’s rank correlation (α = 0.05). Results: No significant differences were found when comparing the three consecutively taken Periotest values and the vertical Zwick values (P > 0.05). In the horizontal dimension, the first Zwick values differed from the second and third values (P 0.05). Conclusions: The Periotest and vertical Zwick values are highly reproducible. The measurements of the two methods do not correlate; therefore, a conversion of Periotest values into metric displacement data is not feasible. The two methods provide different valuable information about tooth mobility. The Periotest method describes the damping characteristics of the periodontal ligament while the Zwick method reveals quantitative metric values.
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Rigidity evaluation of quartz‐fiber splints compared with wire‐composite splints
Dental Traumatology, 2011Co-Authors: Christine Berthold, Friedrich Johannes Auer, Sergej Potapov, Anselm PetscheltAbstract:– Aim: To evaluate the influence of reinforcement material on in vitro dental splint rigidity. Materials and Methods: A custom-made Artificial Model was used. The central incisors simulated ‘injured’ teeth with increased mobility, and the lateral incisors served as ‘uninjured’ teeth with physiologic mobility. The Periotest and Zwick methods were used to assess horizontal and vertical tooth mobility before and after splinting, and relative splint effect (SpErel) was calculated. Teeth 12–22 were splinted using two wire-composite splints (WCS), WCS1 (Dentaflex 0.45 mm), and WCS2 (Strengtheners 0.8 × 1.8 mm) as well as four quartz-fiber splints, QS1 (Quartz Splint UD 1.5 mm), QS2 (Quartz Splint Rope 1.5 mm), QS3 (Quartz Splint Woven 2.5 mm), and QS4 (dry fibers 667 tex). The influence of the splint type was evaluated using anova, Tukey range, and the Dunnett-T3 test (α = 0.05). To test the influence of initial tooth mobility, the t-test was applied (α = 0.05). Results: Reinforcement materials significantly influenced splint rigidity (P
Dario Carugo - One of the best experts on this subject based on the ideXlab platform.
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investigating the flow dynamics in the obstructed and stented ureter by means of a biomimetic Artificial Model
PLOS ONE, 2014Co-Authors: Francesco Clavica, Xuefeng Zhao, Motaz Elmahdy, Marcus J Drake, Xunli Zhang, Dario CarugoAbstract:Double-J stenting is the most common clinical method employed to restore the upper urinary tract drainage, in the presence of a ureteric obstruction. After implant, stents provide an immediate pain relief by decreasing the pressure in the renal pelvis (P). However, their long-term usage can cause infections and encrustations, due to bacterial colonization and crystal deposition on the stent surface, respectively. The performance of double-J stents - and in general of all ureteric stents - is thought to depend significantly on urine flow field within the stented ureter. However very little fundamental research about the role played by fluid dynamic parameters on stent functionality has been conducted so far. These parameters are often difficult to assess in-vivo, requiring the implementation of laborious and expensive experimental protocols. The aim of the present work was therefore to develop an Artificial Model of the ureter (i.e. ureter Model, UM) to mimic the fluid dynamic environment in a stented ureter. The UM was designed to reflect the geometry of pig ureters, and to investigate the values of fluid dynamic viscosity (μ), volumetric flow rate (Q) and severity of ureteric obstruction (OB%) which may cause critical pressures in the renal pelvis. The distributed obstruction derived by the sole stent insertion was also quantified. In addition, flow visualisation experiments and computational simulations were performed in order to further characterise the flow field in the UM. Unique characteristics of the flow dynamics in the obstructed and stented ureter have been revealed with using the developed UM.
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EMBC - An Artificial Model for studying fluid dynamics in the obstructed and stented ureter
2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2013Co-Authors: Dario Carugo, Xuefeng Zhao, Motaz Elmahdy, Marcus J Drake, Xunli Zhang, Francesco ClavicaAbstract:Fluid dynamics in the obstructed and stented ureter represents a non-trivial subject of investigation since, after stent placement, the urine can flow either through the stent lumen or in the extra-luminal space located between the stent wall and the ureteric inner wall. Fluid dynamic investigations can help understanding the phenomena behind stent failure (e.g. stent occlusions due to bacterial colonization and encrustations), which may cause kidney damage due to the associated high pressures generated in the renal pelvis. In this work a microfluidic-based transparent device (ureter Model, UM) has been developed to simulate the fluid dynamic environment in a stented ureter. UM geometry has been designed from measurements on pig ureters. Pressure in the renal pelvis compartment has been measured against three variables: fluid viscosity (μ), volumetric flow rate (Q) and level of obstruction (OB%). The measurements allowed a quantification of the critical combination of μ, Q and OB% values which may lead to critical pressure levels in the kidney. Moreover, an example showing the possibility of applying particle image velocimetry (PIV) technology to the developed microfluidic device is provided.
Marcus J Drake - One of the best experts on this subject based on the ideXlab platform.
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investigating the flow dynamics in the obstructed and stented ureter by means of a biomimetic Artificial Model
PLOS ONE, 2014Co-Authors: Francesco Clavica, Xuefeng Zhao, Motaz Elmahdy, Marcus J Drake, Xunli Zhang, Dario CarugoAbstract:Double-J stenting is the most common clinical method employed to restore the upper urinary tract drainage, in the presence of a ureteric obstruction. After implant, stents provide an immediate pain relief by decreasing the pressure in the renal pelvis (P). However, their long-term usage can cause infections and encrustations, due to bacterial colonization and crystal deposition on the stent surface, respectively. The performance of double-J stents - and in general of all ureteric stents - is thought to depend significantly on urine flow field within the stented ureter. However very little fundamental research about the role played by fluid dynamic parameters on stent functionality has been conducted so far. These parameters are often difficult to assess in-vivo, requiring the implementation of laborious and expensive experimental protocols. The aim of the present work was therefore to develop an Artificial Model of the ureter (i.e. ureter Model, UM) to mimic the fluid dynamic environment in a stented ureter. The UM was designed to reflect the geometry of pig ureters, and to investigate the values of fluid dynamic viscosity (μ), volumetric flow rate (Q) and severity of ureteric obstruction (OB%) which may cause critical pressures in the renal pelvis. The distributed obstruction derived by the sole stent insertion was also quantified. In addition, flow visualisation experiments and computational simulations were performed in order to further characterise the flow field in the UM. Unique characteristics of the flow dynamics in the obstructed and stented ureter have been revealed with using the developed UM.
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EMBC - An Artificial Model for studying fluid dynamics in the obstructed and stented ureter
2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2013Co-Authors: Dario Carugo, Xuefeng Zhao, Motaz Elmahdy, Marcus J Drake, Xunli Zhang, Francesco ClavicaAbstract:Fluid dynamics in the obstructed and stented ureter represents a non-trivial subject of investigation since, after stent placement, the urine can flow either through the stent lumen or in the extra-luminal space located between the stent wall and the ureteric inner wall. Fluid dynamic investigations can help understanding the phenomena behind stent failure (e.g. stent occlusions due to bacterial colonization and encrustations), which may cause kidney damage due to the associated high pressures generated in the renal pelvis. In this work a microfluidic-based transparent device (ureter Model, UM) has been developed to simulate the fluid dynamic environment in a stented ureter. UM geometry has been designed from measurements on pig ureters. Pressure in the renal pelvis compartment has been measured against three variables: fluid viscosity (μ), volumetric flow rate (Q) and level of obstruction (OB%). The measurements allowed a quantification of the critical combination of μ, Q and OB% values which may lead to critical pressure levels in the kidney. Moreover, an example showing the possibility of applying particle image velocimetry (PIV) technology to the developed microfluidic device is provided.
Xuefeng Zhao - One of the best experts on this subject based on the ideXlab platform.
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investigating the flow dynamics in the obstructed and stented ureter by means of a biomimetic Artificial Model
PLOS ONE, 2014Co-Authors: Francesco Clavica, Xuefeng Zhao, Motaz Elmahdy, Marcus J Drake, Xunli Zhang, Dario CarugoAbstract:Double-J stenting is the most common clinical method employed to restore the upper urinary tract drainage, in the presence of a ureteric obstruction. After implant, stents provide an immediate pain relief by decreasing the pressure in the renal pelvis (P). However, their long-term usage can cause infections and encrustations, due to bacterial colonization and crystal deposition on the stent surface, respectively. The performance of double-J stents - and in general of all ureteric stents - is thought to depend significantly on urine flow field within the stented ureter. However very little fundamental research about the role played by fluid dynamic parameters on stent functionality has been conducted so far. These parameters are often difficult to assess in-vivo, requiring the implementation of laborious and expensive experimental protocols. The aim of the present work was therefore to develop an Artificial Model of the ureter (i.e. ureter Model, UM) to mimic the fluid dynamic environment in a stented ureter. The UM was designed to reflect the geometry of pig ureters, and to investigate the values of fluid dynamic viscosity (μ), volumetric flow rate (Q) and severity of ureteric obstruction (OB%) which may cause critical pressures in the renal pelvis. The distributed obstruction derived by the sole stent insertion was also quantified. In addition, flow visualisation experiments and computational simulations were performed in order to further characterise the flow field in the UM. Unique characteristics of the flow dynamics in the obstructed and stented ureter have been revealed with using the developed UM.
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EMBC - An Artificial Model for studying fluid dynamics in the obstructed and stented ureter
2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2013Co-Authors: Dario Carugo, Xuefeng Zhao, Motaz Elmahdy, Marcus J Drake, Xunli Zhang, Francesco ClavicaAbstract:Fluid dynamics in the obstructed and stented ureter represents a non-trivial subject of investigation since, after stent placement, the urine can flow either through the stent lumen or in the extra-luminal space located between the stent wall and the ureteric inner wall. Fluid dynamic investigations can help understanding the phenomena behind stent failure (e.g. stent occlusions due to bacterial colonization and encrustations), which may cause kidney damage due to the associated high pressures generated in the renal pelvis. In this work a microfluidic-based transparent device (ureter Model, UM) has been developed to simulate the fluid dynamic environment in a stented ureter. UM geometry has been designed from measurements on pig ureters. Pressure in the renal pelvis compartment has been measured against three variables: fluid viscosity (μ), volumetric flow rate (Q) and level of obstruction (OB%). The measurements allowed a quantification of the critical combination of μ, Q and OB% values which may lead to critical pressure levels in the kidney. Moreover, an example showing the possibility of applying particle image velocimetry (PIV) technology to the developed microfluidic device is provided.