Removal effect of DNA contamination by hydrogen peroxide plasma compared to ethylene-oxide gas.

We examined the ability of hydrogen peroxide plasma (HPP) to remove DNA contamination, to evaluate whether it is a suitable forensic-grade treatment under ISO 18385. HPP treatment was compared to ethylene-oxide gas (EOG) treatment, which is required by ISO 18385. For the evaluation, commercial control DNA solution and cultured cells sprinkled on Petri dishes were used, and the DNA fragments (214 and 80 bp autosomal DNA fragments and 75 bp Y chromosome fragment) were quantified. HPP treatment was performed up to four times and EOG treatment was performed once. Performing HPP treatment three times was as effective as EOG treatment, with all fragments decreasing to below 1/1,000 in DNA solution. With STR and Y-STR typing, no alleles were detected for three HPP treatments of control DNA using the original amount, i.e., 1 ng. Therefore, HPP appears useful for removing DNA contamination. For cells sprinkled on Petri dishes, the DNA degradation abilities of the HPP and EOG were comparable. However, less DNA was degraded with the HPP and EOG and neither met the ISO criteria. Although the current version of ISO 18385 recommends an evaluation method using cultured cells sprinkled on Petri dishes, it needs to be revised. These findings should be considered when revising ISO 18385.

Effect of Sterilization on Bond Strength and Mechanical Properties of Fiber Posts.

PURPOSE: To determine the effects of two different sterilization methods on the pull-out bond strength, flexural strength, and elastic modulus of glass-fiber posts. MATERIALS AND METHODS: A total of 69 glass-fiber posts were used. The posts were divided into three groups according to applied sterilization method: 1) control, 2) ethylene oxide gas (EOG), and 3) autoclave. The microstructure of three posts from each group was evaluated by SEM and energy-dispersive X-ray spectroscopy (EDS). Thirty glass-fiber posts were used to evaluate pull-out bond strength. The three-point bending test was performed to analyze the flexural strength on another 30 glass-fiber posts. Failure modes were categorized microscopically after the pull-out test. After the three-point bending test, micromorphology at the bending area was examined using SEM. RESULTS: One-way ANOVA indicated no statistically significant differences among the group means in terms of bond strength (p > 0.05), flexural strength (p > 0.05), or elastic modulus (p > 0.05). EDS revealed that the weight percentage of surface oxygen atoms in the EOG- and autoclave-sterilization groups were significantly higher. SEM images were similar. CONCLUSION: The results of this study show that glass-fiber posts can be sterilized either by autoclave or EOG when necessary, without any negative effect on bond strength, flexural strength, or elastic modulus.

Tejido óseo esponjoso esterilizado con gas óxido de etileno / Spongy bone tissue sterilized with ethylene oxide gas / Tissu osseux spongieux stérilisé à l'oxyde d'éthylène gazeux

Objetivo: comprobar las propiedades esterilizantes del gas óxido de etileno sobre el hueso esponjoso empleado como implante en la clínica médica, fundamentalmente su eficacia para determinados microorganismos y el tiempo necesario de su uso en autoclave industrial. Métodos: se prepararon 54 porciones de tejido óseo esponjoso en forma de cubo separados en 3 grupos de 18 porciones cada uno. El primer grupo se empleó para evaluar un método de contaminación bacteriológica con cepas de microorganismos conocidos. El segundo y tercer grupo una vez contaminados con los microorganismos conocidos se sometieron a la acción del gas óxido de etileno en subgrupos de 6, durante 60, 90 y 120 min. Resultados: en el primer grupo el 100 % de las muestras contaminadas se presentaron positivas. En los grupos segundo y tercero la efectividad del gas óxido de etileno resultó de 100 % a los 120 min. Conclusión: este método es seguro, por lo que es apropiado para el empleo en la clínica médica.

Objective: verify the sterilizing properties of ethylene oxide gas over the spongy bone used for implants in medical practice, mainly its efficacy against certain microorganisms and the time required for sterilization in industrial autoclaves. Methods: 54 cube-shaped spongy bone tissue samples were prepared and distributed into 3 groups, each with 18 samples. The first group was used to evaluate a bacteriological contamination method with strains of known microorganisms. Upon contamination with the known microorganisms, the second and third groups were subjected to the effect of ethylene oxide gas in subgroups of 6 samples during 60, 90 and 120 minutes. Results: in the first group 100 % of the samples contaminated were positive. In the second and third groups, the effectiveness of ethylene oxide gas was 100 % at 120 minutes. Conclusion: this is a safe method appropriate for use in medical practice.

Objectif: confirmer les propriétés stérilisantes de l'oxyde d'éthylène gazeux sur l'os spongieux utilisé comme implant dans la clinique médicale, notamment son efficacité contre certains microorganismes, et le temps nécessaire pour l'utiliser dans un autoclave industriel. Méthodes: cinquante-et-quatre portions de tissu osseux spongieux ont été préparées sous forme de cube, et séparées en 3 groupes de dix-huit portions chacun. Le premier groupe a été utilisé pour évaluer une méthode de contamination bactériologique à souches de microorganismes connus. Une fois contaminés par des microorganismes connus, les deuxième et troisième groupes ont été soumis à l'action de l'oxyde d'éthylène gazeux en sous-groupes de 6 au cours de 60, 90 et 120 minutes. Résultats: dans le premier groupe, 100 % des échantillons contaminés ont été positifs. Dans les deuxième et troisième groupes, l'efficacité de ce gaz a réussi 100 % à 120 minutes. Conclusion: cette méthode est sure, donc appropriée, pour la clinique médicale.

Tejido óseo esponjoso esterilizado con gas óxido de etileno / Spongy bone tissue sterilized with ethylene oxide gas

Objetivo: comprobar las propiedades esterilizantes del gas óxido de etileno sobre el hueso esponjoso empleado como implante en la clínica médica, fundamentalmente su eficacia para determinados microorganismos y el tiempo necesario de su uso en autoclave industrial. Métodos: se prepararon 54 porciones de tejido óseo esponjoso en forma de cubo separados en 3 grupos de 18 porciones cada uno. El primer grupo se empleó para evaluar un método de contaminación bacteriológica con cepas de microorganismos conocidos. El segundo y tercer grupo una vez contaminados con los microorganismos conocidos se sometieron a la acción del gas óxido de etileno en subgrupos de 6, durante 60, 90 y 120 min. Resultados: en el primer grupo el 100 por ciento de las muestras contaminadas se presentaron positivas. En los grupos segundo y tercero la efectividad del gas óxido de etileno resultó de 100 por ciento a los 120 min. Conclusión: este método es seguro, por lo que es apropiado para el empleo en la clínica médica(AU)

Objective: verify the sterilizing properties of ethylene oxide gas over the spongy bone used for implants in medical practice, mainly its efficacy against certain microorganisms and the time required for sterilization in industrial autoclaves. Methods: 54 cube-shaped spongy bone tissue samples were prepared and distributed into 3 groups, each with 18 samples. The first group was used to evaluate a bacteriological contamination method with strains of known microorganisms. Upon contamination with the known microorganisms, the second and third groups were subjected to the effect of ethylene oxide gas in subgroups of 6 samples during 60, 90 and 120 minutes. Results: in the first group 100 percent of the samples contaminated were positive. In the second and third groups, the effectiveness of ethylene oxide gas was 100 percent at 120 minutes. Conclusion: this is a safe method appropriate for use in medical practice(AU)

Apósito biológico esterilizado con gas óxido de etileno / A biological dressing sterilized using ethylene oxide gas

Objetivo: se presentó el resultado de una investigación preclínica dirigida a comprobar el poder esterilizante del gas óxido de etileno sobre la piel porcina empleada como apósito biológico. Métodos: se contaminaron 2 grupos de 60 muestras cada uno, de piel porcina liofilizada con una cepa de estafilococo coagulasa positivo y Pseudomona aeruginosa, respectivamente. El 25 por ciento de las muestras de cada grupo se envió al laboratorio de microbiología para comprobar la efectividad del método de contaminación. El 75 por ciento restante se trató durante diferentes períodos en una cámara de gas óxido de etileno y, posteriormente, se enviaron al laboratorio de microbiología para comprobar el grado de esterilidad. Resultados: se demostró la alta efectividad del gas óxido de etileno para esterilizar la piel porcina que es empleada como apósito biológico. Conclusiones: este método es seguro, por lo que es apropiado para el empleo en la clínica médica

Objective: to present the result from a preclinical research aimed to verify the sterilizing power of ethylene oxide gas on the porcine skin used as a biological dressing. Methods: two groups of 60 samples each of lyophilized porcine skin were contaminated with a strain of positive-coagulase staphylococcus and Pseudomona aeruginosa, respectively. The 25 percent of samples of each group was sent to microbiology laboratory to verify the effectiveness of contamination method. The remainder 75 percent was treated in different periods in a chamber of ethylene oxide gas and later, was sent to the above laboratory to verify the sterility degree. Results: it was demonstrated the effectiveness of the ethylene oxide gas to sterilize the porcine skin, which is used as a biological dressing. Conclusions: this method is safe, therefore it is appropriate to use in the medical clinic

Apósito biológico esterilizado con gas óxido de etileno / A biological dressing sterilized using ethylene oxide gas

Objetivo: se presentó el resultado de una investigación preclínica dirigida a comprobar el poder esterilizante del gas óxido de etileno sobre la piel porcina empleada como apósito biológico. Métodos: se contaminaron 2 grupos de 60 muestras cada uno, de piel porcina liofilizada con una cepa de estafilococo coagulasa positivo y Pseudomona aeruginosa, respectivamente. El 25 por ciento de las muestras de cada grupo se envió al laboratorio de microbiología para comprobar la efectividad del método de contaminación. El 75 por ciento restante se trató durante diferentes períodos en una cámara de gas óxido de etileno y, posteriormente, se enviaron al laboratorio de microbiología para comprobar el grado de esterilidad. Resultados: se demostró la alta efectividad del gas óxido de etileno para esterilizar la piel porcina que es empleada como apósito biológico. Conclusiones: este método es seguro, por lo que es apropiado para el empleo en la clínica médica(AU)

Objective: to present the result from a preclinical research aimed to verify the sterilizing power of ethylene oxide gas on the porcine skin used as a biological dressing. Methods: two groups of 60 samples each of lyophilized porcine skin were contaminated with a strain of positive-coagulase staphylococcus and Pseudomona aeruginosa, respectively. The 25 percent of samples of each group was sent to microbiology laboratory to verify the effectiveness of contamination method. The remainder 75 percent was treated in different periods in a chamber of ethylene oxide gas and later, was sent to the above laboratory to verify the sterility degree. Results: it was demonstrated the effectiveness of the ethylene oxide gas to sterilize the porcine skin, which is used as a biological dressing. Conclusions: this method is safe, therefore it is appropriate to use in the medical clinic(AU)

The effect of NaOCl treatment and sterilization procedures on the corrosion of endodontic files / 대한치과보존학회지

A variety files made of stainless steel (S-S) or nickel-titanium (Ni-Ti) are used during endodontic treatment. The purpose of this study was to evaluate the corrosion susceptibility of S-S and Ni-Ti endodontic files. Three brands of files were used for this study: K-flex(R) S-S files (Maillefer, USA), Profile(R) Ni-Ti files (Maillefer, USA), K-3(R) Ni-Ti files (SybronEndo, USA). 120 files of each brands (21mm, ISO size #20) were divided into 12 groups according to 1) sterilization methods using Autoclave or Ethylene Oxide (E-O) gas, 2) Irrigation solutions using 5.25 % NaOCl or Saline, 3) the number of sterilization (1, 5, 10 times). After above procedures, each of the files was inspected by three examiners with a light microscope and camera at X25. Each file was judged and ranked according to the following criteria: 0; no corrosion, 1; mild corrosion, 2; moderate corrosion, and 3; severe corrosion. The files of high score were examined under the Scanning Electron Microscope. Data were statistically analyzed with the Kruskal-Wallis test (p < 0.05). Most of the ten time-autoclaved files had showed mild to moderate corrosion. But, one or five time-autoclaved files did not show corrosive surface. NaOCl treatment and E-O gas sterilization did not influence on corrosion. There was a significant difference in corrosion susceptibility between sterilization methods and the number of autoclaving. However, there was no significant difference between brands and file materials.

Safety and Efficacy of Ethylene Oxide Gas Sterilized Acellular Allogenic Dermis

The human acelluar allogenic dermis has been used for soft tissue augmentation of sunken areas. Because of high price, extra-acelluar allogenic dermis is resterilized after being used. The purpose of this experiment is to evaluate the safety and efficacy of ethylene oxide (E.O) gas sterilized acellular allogenic dermal graft(Sure Derm(R)). Twenty-four white rats, weighing about 200 grams and of 5 weeks of age were divided into 3 groups. The prepared SureDerm(R) sheets(10x10mm sized , each 1 mm in thickness) were implanted into the pockets of back area. Biopsy specimens were taken after 4, 8 and 12 weeks and examined histologically for inflammatory reaction, neocollagen synthesis. The initial volume of the graft was measured by immersing it in a 2cc of normal saline and the volume of fluid displaced was checked. The changes in graft volume were measured by the same method. There was a tiny decrease in the volume of the E.O. gas sterilized graft. However, there was no significant difference in the survival rate among the groups(p<0.05). Histological analysis demonstrated progressive monocytes and fibroblast infiltration, sparce collagen bundle organization with time in E.O. gas sterilized grafts. Our experimental study suggests that E.O. gas re- sterilized SureDerm(R) might not be a safe material to use as an implant.