The Experts below are selected from a list of 1584 Experts worldwide ranked by ideXlab platform
B Kirk - One of the best experts on this subject based on the ideXlab platform.
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failure of non vacuum steam sterilization processes for dental handpieces
Journal of Hospital Infection, 2017Co-Authors: Sandra Winter, David F Lappin, G Mcdonagh, Andrew Smith, B KirkAbstract:Summary Background Dental handpieces are used in critical and semi-critical operative interventions. Although some dental professional bodies recommend that dental handpieces are sterilized between patient use there is a lack of clarity and understanding of the effectiveness of different steam sterilization processes. The internal mechanisms of dental handpieces contain narrow lumens (0.8–2.3 mm) which can impede the removal of air and ingress of saturated steam required to achieve sterilization conditions. Aim To identify the extent of sterilization failure in dental handpieces using a non-vacuum process. Methods In-vitro and in-vivo investigations were conducted on widely used UK bench-top steam Sterilizers and three different types of dental handpieces. The sterilization process was monitored inside the lumens of dental handpieces using thermometric (TM; dataloggers), chemical indicator (CI), and biological indicator (BI) methods. Findings All three methods of assessing achievement of sterility within dental handpieces that had been exposed to non-vacuum sterilization conditions demonstrated a significant number of failures [CI: 8/3024 (fails/no. of tests); BI: 15/3024; TM: 56/56] compared to vacuum sterilization conditions (CI: 2/1944; BI: 0/1944; TM: 0/36). The dental handpiece most likely to fail sterilization in the non-vacuum process was the surgical handpiece. Non-vacuum Sterilizers located in general dental practice had a higher rate of sterilization failure (CI: 25/1620; BI: 32/1620; TM: 56/56) with no failures in vacuum process. Conclusion Non-vacuum downward/gravity displacement, type N steam Sterilizers are an unreliable method for sterilization of dental handpieces in general dental practice. The handpiece most likely to fail sterilization is the type most frequently used for surgical interventions.
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investigating steam penetration using thermometric methods in dental handpieces with narrow internal lumens during sterilizing processes with non vacuum or vacuum processes
Journal of Hospital Infection, 2017Co-Authors: Sandra Winter, David F Lappin, G Mcdonagh, Andrew Smith, B KirkAbstract:Summary Background Dental handpieces are required to be sterilized between patient use. Vacuum steam sterilization processes with fractionated pre/post-vacuum phases or unique cycles for specified medical devices are required for hollow instruments with internal lumens to assure successful air removal. Entrapped air will compromise achievement of required sterilization conditions. Many countries and professional organizations still advocate non-vacuum sterilization processes for these devices. Aim To investigate non-vacuum downward/gravity displacement, type-N steam sterilization of dental handpieces, using thermometric methods to measure time to achieve sterilization temperature at different handpiece locations. Methods Measurements at different positions within air turbines were undertaken with thermocouples and data loggers. Two examples of widely used UK benchtop steam Sterilizers were tested: a non-vacuum benchtop Sterilizer (Little Sister 3; Eschmann, Lancing, UK) and a vacuum benchtop Sterilizer (Lisa; W&H, Burmoos, Austria). Each Sterilizer cycle was completed with three handpieces and each cycle in triplicate. Findings A total of 140 measurements inside dental handpiece lumens were recorded. The non-vacuum process failed (time range: 0–150 s) to reliably achieve sterilization temperatures within the time limit specified by the international standard (15 s equilibration time). The measurement point at the base of the handpiece failed in all test runs ( N = 9) to meet the standard. No failures were detected with the vacuum steam sterilization type B process with fractionated pre-vacuum and post-vacuum phases. Conclusion Non-vacuum downward/gravity displacement, type-N steam sterilization processes are unreliable in achieving sterilization conditions inside dental handpieces, and the base of the handpiece is the site most likely to fail.
Sandra Winter - One of the best experts on this subject based on the ideXlab platform.
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failure of non vacuum steam sterilization processes for dental handpieces
Journal of Hospital Infection, 2017Co-Authors: Sandra Winter, David F Lappin, G Mcdonagh, Andrew Smith, B KirkAbstract:Summary Background Dental handpieces are used in critical and semi-critical operative interventions. Although some dental professional bodies recommend that dental handpieces are sterilized between patient use there is a lack of clarity and understanding of the effectiveness of different steam sterilization processes. The internal mechanisms of dental handpieces contain narrow lumens (0.8–2.3 mm) which can impede the removal of air and ingress of saturated steam required to achieve sterilization conditions. Aim To identify the extent of sterilization failure in dental handpieces using a non-vacuum process. Methods In-vitro and in-vivo investigations were conducted on widely used UK bench-top steam Sterilizers and three different types of dental handpieces. The sterilization process was monitored inside the lumens of dental handpieces using thermometric (TM; dataloggers), chemical indicator (CI), and biological indicator (BI) methods. Findings All three methods of assessing achievement of sterility within dental handpieces that had been exposed to non-vacuum sterilization conditions demonstrated a significant number of failures [CI: 8/3024 (fails/no. of tests); BI: 15/3024; TM: 56/56] compared to vacuum sterilization conditions (CI: 2/1944; BI: 0/1944; TM: 0/36). The dental handpiece most likely to fail sterilization in the non-vacuum process was the surgical handpiece. Non-vacuum Sterilizers located in general dental practice had a higher rate of sterilization failure (CI: 25/1620; BI: 32/1620; TM: 56/56) with no failures in vacuum process. Conclusion Non-vacuum downward/gravity displacement, type N steam Sterilizers are an unreliable method for sterilization of dental handpieces in general dental practice. The handpiece most likely to fail sterilization is the type most frequently used for surgical interventions.
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investigating steam penetration using thermometric methods in dental handpieces with narrow internal lumens during sterilizing processes with non vacuum or vacuum processes
Journal of Hospital Infection, 2017Co-Authors: Sandra Winter, David F Lappin, G Mcdonagh, Andrew Smith, B KirkAbstract:Summary Background Dental handpieces are required to be sterilized between patient use. Vacuum steam sterilization processes with fractionated pre/post-vacuum phases or unique cycles for specified medical devices are required for hollow instruments with internal lumens to assure successful air removal. Entrapped air will compromise achievement of required sterilization conditions. Many countries and professional organizations still advocate non-vacuum sterilization processes for these devices. Aim To investigate non-vacuum downward/gravity displacement, type-N steam sterilization of dental handpieces, using thermometric methods to measure time to achieve sterilization temperature at different handpiece locations. Methods Measurements at different positions within air turbines were undertaken with thermocouples and data loggers. Two examples of widely used UK benchtop steam Sterilizers were tested: a non-vacuum benchtop Sterilizer (Little Sister 3; Eschmann, Lancing, UK) and a vacuum benchtop Sterilizer (Lisa; W&H, Burmoos, Austria). Each Sterilizer cycle was completed with three handpieces and each cycle in triplicate. Findings A total of 140 measurements inside dental handpiece lumens were recorded. The non-vacuum process failed (time range: 0–150 s) to reliably achieve sterilization temperatures within the time limit specified by the international standard (15 s equilibration time). The measurement point at the base of the handpiece failed in all test runs ( N = 9) to meet the standard. No failures were detected with the vacuum steam sterilization type B process with fractionated pre-vacuum and post-vacuum phases. Conclusion Non-vacuum downward/gravity displacement, type-N steam sterilization processes are unreliable in achieving sterilization conditions inside dental handpieces, and the base of the handpiece is the site most likely to fail.
Christoph Hochenauer - One of the best experts on this subject based on the ideXlab platform.
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cfd investigations of steam penetration air removal and condensation inside hollow loads and cavities
Applied Thermal Engineering, 2019Co-Authors: Manuel Feurhuber, Marino Magno, Marco Miranda, Christoph HochenauerAbstract:Abstract Steam sterilization is the most commonly used method to sterilize re-usable medical devices. All non-condensable gases (NCGs) must be removed from every hollow space within the medical device in order to guarantee the high heat transfer rates that result from wall condensation. In this work, a computational fluid dynamics (CFD) model was developed to simulate the fluid flow, temperature, heat transfer, and steam penetration inside the steam Sterilizer with a particular emphasis on hollow loads (cavities). The flow inside the steam Sterilizer was modeled with a three-phase Eulerian-Eulerian model, which includes evaporation and condensation effects. A very numerically inexpensive model was developed and implemented into the CFD code in order to calculate the heat transfer that occurs due to wall condensation in the presence of NCGs. The CFD model was validated by the measurements of temperature, pressure, and NCGs content after different cycle times. The average error between the measured pressures and temperatures and the results of the simulations were 0.16% and 0.54%, respectively. Furthermore, the steam penetration at the ends of the hollow loads was measured using chemical indicators. The simulation results show that a steam concentration of approximately 5% is sufficient to change the color of the chemical indicators. The CFD model developed is able to predict the volume fraction of NCGs, as well as steam penetration inside the steam Sterilizer, including the hollow loads (cavities). Thus, it should be easier for future developers of steam Sterilizers to investigate steam penetration within hollow loads and cavities.
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prediction of the fluid flow heat transfer and inactivation of microorganism at medical devices in modern steam Sterilizers using computational fluid dynamics
Applied Thermal Engineering, 2017Co-Authors: Manuel Feurhuber, A Cattide, Marino Magno, Marco Miranda, Rene Josef Prieler, Christoph HochenauerAbstract:Abstract Medical devices, which are wrapped in pouches, are generally sterilized using steam Sterilizers (autoclaves) in order to achieve a certain level of sterility. During the sterilization process, the medical devices are heated up to a predefined temperature of 134 ° C at a pressure level of 3.1 bar. Steam is commonly used in the Sterilizers because of the high heat transfer rate to the medical devices due to wall condensation effects. The sterility level of the devices is represented by the Safety Assurance Level (SAL) which depicts the amount of inactivated microorganisms at the surface. Since the entire sterilization process consists of several different transport phenomena, such as fluid flow, heat transfer, phase change etc., the prediction of the medical devices’ SAL is a complex task. In the present paper, Computational Fluid Dynamics (CFD) was used to calculate the temperature, pressure, steam quality and, consequently, the medical devices’ SAL temporarily and spatially resolved. For that purpose, model approaches to predict the steam penetration of the pouches and the heat transfer due to wall condensation of the steam were developed and implemented in the CFD code. Therefore, an accurate simulation of the temperature and steam quality in the Sterilizer is possible. The CFD results were compared to the measured temperatures of the steam and the devices. The comparison corresponded well for the entire sterilization process and provided a sound basis for a precise simulation of the SAL which was done by a first order reaction kinetics based on the Arrhenius approach. The results presented in this paper show that the developed CFD model is able to predict the temperature, pressure, steam quality as well as the progress of the sterilization process in an accurate manner, and is beneficial for future developments of steam Sterilizers in the medical industry.
Andrew Smith - One of the best experts on this subject based on the ideXlab platform.
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failure of non vacuum steam sterilization processes for dental handpieces
Journal of Hospital Infection, 2017Co-Authors: Sandra Winter, David F Lappin, G Mcdonagh, Andrew Smith, B KirkAbstract:Summary Background Dental handpieces are used in critical and semi-critical operative interventions. Although some dental professional bodies recommend that dental handpieces are sterilized between patient use there is a lack of clarity and understanding of the effectiveness of different steam sterilization processes. The internal mechanisms of dental handpieces contain narrow lumens (0.8–2.3 mm) which can impede the removal of air and ingress of saturated steam required to achieve sterilization conditions. Aim To identify the extent of sterilization failure in dental handpieces using a non-vacuum process. Methods In-vitro and in-vivo investigations were conducted on widely used UK bench-top steam Sterilizers and three different types of dental handpieces. The sterilization process was monitored inside the lumens of dental handpieces using thermometric (TM; dataloggers), chemical indicator (CI), and biological indicator (BI) methods. Findings All three methods of assessing achievement of sterility within dental handpieces that had been exposed to non-vacuum sterilization conditions demonstrated a significant number of failures [CI: 8/3024 (fails/no. of tests); BI: 15/3024; TM: 56/56] compared to vacuum sterilization conditions (CI: 2/1944; BI: 0/1944; TM: 0/36). The dental handpiece most likely to fail sterilization in the non-vacuum process was the surgical handpiece. Non-vacuum Sterilizers located in general dental practice had a higher rate of sterilization failure (CI: 25/1620; BI: 32/1620; TM: 56/56) with no failures in vacuum process. Conclusion Non-vacuum downward/gravity displacement, type N steam Sterilizers are an unreliable method for sterilization of dental handpieces in general dental practice. The handpiece most likely to fail sterilization is the type most frequently used for surgical interventions.
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investigating steam penetration using thermometric methods in dental handpieces with narrow internal lumens during sterilizing processes with non vacuum or vacuum processes
Journal of Hospital Infection, 2017Co-Authors: Sandra Winter, David F Lappin, G Mcdonagh, Andrew Smith, B KirkAbstract:Summary Background Dental handpieces are required to be sterilized between patient use. Vacuum steam sterilization processes with fractionated pre/post-vacuum phases or unique cycles for specified medical devices are required for hollow instruments with internal lumens to assure successful air removal. Entrapped air will compromise achievement of required sterilization conditions. Many countries and professional organizations still advocate non-vacuum sterilization processes for these devices. Aim To investigate non-vacuum downward/gravity displacement, type-N steam sterilization of dental handpieces, using thermometric methods to measure time to achieve sterilization temperature at different handpiece locations. Methods Measurements at different positions within air turbines were undertaken with thermocouples and data loggers. Two examples of widely used UK benchtop steam Sterilizers were tested: a non-vacuum benchtop Sterilizer (Little Sister 3; Eschmann, Lancing, UK) and a vacuum benchtop Sterilizer (Lisa; W&H, Burmoos, Austria). Each Sterilizer cycle was completed with three handpieces and each cycle in triplicate. Findings A total of 140 measurements inside dental handpiece lumens were recorded. The non-vacuum process failed (time range: 0–150 s) to reliably achieve sterilization temperatures within the time limit specified by the international standard (15 s equilibration time). The measurement point at the base of the handpiece failed in all test runs ( N = 9) to meet the standard. No failures were detected with the vacuum steam sterilization type B process with fractionated pre-vacuum and post-vacuum phases. Conclusion Non-vacuum downward/gravity displacement, type-N steam sterilization processes are unreliable in achieving sterilization conditions inside dental handpieces, and the base of the handpiece is the site most likely to fail.
G Mcdonagh - One of the best experts on this subject based on the ideXlab platform.
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failure of non vacuum steam sterilization processes for dental handpieces
Journal of Hospital Infection, 2017Co-Authors: Sandra Winter, David F Lappin, G Mcdonagh, Andrew Smith, B KirkAbstract:Summary Background Dental handpieces are used in critical and semi-critical operative interventions. Although some dental professional bodies recommend that dental handpieces are sterilized between patient use there is a lack of clarity and understanding of the effectiveness of different steam sterilization processes. The internal mechanisms of dental handpieces contain narrow lumens (0.8–2.3 mm) which can impede the removal of air and ingress of saturated steam required to achieve sterilization conditions. Aim To identify the extent of sterilization failure in dental handpieces using a non-vacuum process. Methods In-vitro and in-vivo investigations were conducted on widely used UK bench-top steam Sterilizers and three different types of dental handpieces. The sterilization process was monitored inside the lumens of dental handpieces using thermometric (TM; dataloggers), chemical indicator (CI), and biological indicator (BI) methods. Findings All three methods of assessing achievement of sterility within dental handpieces that had been exposed to non-vacuum sterilization conditions demonstrated a significant number of failures [CI: 8/3024 (fails/no. of tests); BI: 15/3024; TM: 56/56] compared to vacuum sterilization conditions (CI: 2/1944; BI: 0/1944; TM: 0/36). The dental handpiece most likely to fail sterilization in the non-vacuum process was the surgical handpiece. Non-vacuum Sterilizers located in general dental practice had a higher rate of sterilization failure (CI: 25/1620; BI: 32/1620; TM: 56/56) with no failures in vacuum process. Conclusion Non-vacuum downward/gravity displacement, type N steam Sterilizers are an unreliable method for sterilization of dental handpieces in general dental practice. The handpiece most likely to fail sterilization is the type most frequently used for surgical interventions.
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investigating steam penetration using thermometric methods in dental handpieces with narrow internal lumens during sterilizing processes with non vacuum or vacuum processes
Journal of Hospital Infection, 2017Co-Authors: Sandra Winter, David F Lappin, G Mcdonagh, Andrew Smith, B KirkAbstract:Summary Background Dental handpieces are required to be sterilized between patient use. Vacuum steam sterilization processes with fractionated pre/post-vacuum phases or unique cycles for specified medical devices are required for hollow instruments with internal lumens to assure successful air removal. Entrapped air will compromise achievement of required sterilization conditions. Many countries and professional organizations still advocate non-vacuum sterilization processes for these devices. Aim To investigate non-vacuum downward/gravity displacement, type-N steam sterilization of dental handpieces, using thermometric methods to measure time to achieve sterilization temperature at different handpiece locations. Methods Measurements at different positions within air turbines were undertaken with thermocouples and data loggers. Two examples of widely used UK benchtop steam Sterilizers were tested: a non-vacuum benchtop Sterilizer (Little Sister 3; Eschmann, Lancing, UK) and a vacuum benchtop Sterilizer (Lisa; W&H, Burmoos, Austria). Each Sterilizer cycle was completed with three handpieces and each cycle in triplicate. Findings A total of 140 measurements inside dental handpiece lumens were recorded. The non-vacuum process failed (time range: 0–150 s) to reliably achieve sterilization temperatures within the time limit specified by the international standard (15 s equilibration time). The measurement point at the base of the handpiece failed in all test runs ( N = 9) to meet the standard. No failures were detected with the vacuum steam sterilization type B process with fractionated pre-vacuum and post-vacuum phases. Conclusion Non-vacuum downward/gravity displacement, type-N steam sterilization processes are unreliable in achieving sterilization conditions inside dental handpieces, and the base of the handpiece is the site most likely to fail.
