In vitro comparison of peracetic acid and autoclave sterilization in the corrosion of orthodontic pliers: a pilot study

ABSTRACT Introduction: The most currently recommended method for sterilization of orthodontic pliers is the autoclave, while peracetic acid has also been shown to be effective in the chemical sterilization process. Objective: This study sought to compare the corrosive effects of peracetic acid and autoclave sterilization process of orthodontic pliers. Methods: Four active tungsten carbide (WC) stainless steel tie-cutting pliers from the manufacturers Quinelato (Rio Claro, SP, Brazil) and ICE (Cajamar, SP, Brazil) were selected. The active ends of the pliers were sectioned, and six active tips were obtained and distributed into the following groups: 1) control group (no sterilization); 2) AC group (two active pliers tips submitted to 100 autoclave sterilization cycles); and 3) AP group (two active pliers tips submitted to 100 cycles of sterilization by immersion in 2% peracetic acid solution for 30 minutes). Results: Chemical analysis using X-ray dispersive energy spectroscopy showed that after autoclave sterilization, only the ICE pliers presented oxidation corrosion (Δ[O] = +24.5%; Δ[Fe] = +5.8%; Δ[WC] = -1.9%). In comparison, following peracetic acid sterilization, both manufacturers ICE (Δ[O] = +1.8%; Δ[Fe] = +18.0%; Δ[WC] = -1.1%) and Quinelato (Δ[O] = +5.3%; Δ[Fe] = -10.4%; Δ[WC] = -15.2%) showed corrosion. The morphological analysis revealed that peracetic acid caused a pitting and localized corrosion in both brands, while the autoclave caused uniform surface corrosion on the ICE pliers. Conclusion: Autoclave application was the sterilization method that generated less corrosive damage to the orthodontic cutting pliers, when compared to the immersion in 2% peracetic acid.

RESUMO Introdução: O método mais recomendado para a esterilização dos alicates ortodônticos é a autoclave; porém, o ácido peracético mostrou-se eficaz no processo de esterilização química. Objetivo: O objetivo do presente estudo foi avaliar o efeito corrosivo do ácido peracético e da autoclave no processo de esterilização de alicates ortodônticos. Métodos: Foram selecionados quatro alicates de corte de amarrilho de aço inoxidável, com ponta ativa de carboneto de tungstênio (WC), das marcas Quinelato (Rio Claro/SP, Brasil) e ICE (Cajamar/SP, Brasil), que foram distribuídos em três grupos: 1) Controle (C), o qual não foi submetido à esterilização; 2) Grupo AC, constituído por duas pontas ativas de alicates submetidas a 100 ciclos de esterilização em autoclave; e 3) Grupo AP, formado por duas pontas ativas de alicates submetidas a 100 ciclos de esterilização por imersão em solução de ácido peracético a 2% durante 30 minutos. Resultados: Por meio da análise química (EDS, energia dispersiva de raios X), constatou-se que, após esterilização em autoclave, somente o alicate ICE apresentou corrosão por oxidação (Δ[O] = +24,5%; Δ[Fe] = +5,8% e Δ[WC] = -1,9%), enquanto na esterilização em ácido peracético, ambas as marcas, ICE (Δ[O] = +1,8%; Δ[Fe] = +18,0% e Δ[WC] = -1,1%) e Quinelato (Δ[O] = +5,3%; Δ[Fe] = -10,4% e Δ[WC] = -15,2%), apresentaram corrosão. A análise morfológica demonstrou que o ácido peracético causou uma corrosão localizada em pite em ambas as marcas, enquanto a autoclave ocasionou uma corrosão superficial uniforme no alicate ICE. Conclusão: A autoclave foi o método de esterilização que gerou menor dano corrosivo aos alicates ortodônticos, em comparação à imersão em ácido peracético a 2%.

Estimation of the autoclave and different surface treatments on microleakage between soft liner and heat-cured acrylic / Estimativa da autoclavagem e diferentes tratamentos de superfície na microinfiltração entre o soft liner e o acrílico termopolimerizável

Objective: The present study was oriented to estimate the effect of different surface treatments on the microleakage between the soft liner and acrylic with and without the use of autoclave as disinfection method. Material and Methods: Sixty samples were split into two groups: the autoclaved groups and non-autoclaved groups. Each one subdivided into three groups: first one without any treatments as a control group; in the second group surface of the samples were treated with CO2 laser (10.6 nm wavelength for 15 seconds), and in the third group the surface was treated with sandblasting (250 µm Al2O3). All the samples exposed to thermocycling, then the microleakage test was evaluated by gauging dye penetration depth between the soft liner and acrylic disc using a digital microscope. Data analyzed statistically by One-way ANOVA and Tukey's post-hoc tests. In addition, t-test was used for comparison between two groups (P-value ≤ 0.05). Results: The maximum mean values for the microleakage were observed in the untreated group (control) followed by the group treated by CO2 laser and the lowest mean value of microleakage was related to the third group for both non-autoclaved and autoclaved groups with significant differences among them. In addition, depending on the use of autoclave, there was non-significant in all studied groups. Conclusions: There was a decrease in the microleakage when the surface treated with CO2laser and sandblast. The use of autoclave did not badly change the microleakage between the soft liner and denture base. (AU)

Objetivo: O presente estudo teve como objetivo estimar o efeito de diferentes tratamentos de superfície na microinfiltração entre o soft liner e o acrílico usando ou não a autoclve como método de desinfecção. Material e Métodos: Sessenta amostras foram divididas em dois grupos: grupo com uso da autoclave e grupo sem uso da autoclave. Cada um subdivide em três grupos: o primeiro sem nenhum tratamento como grupo controle; no segundo grupo, a superfície das amostras foi tratada com laser de CO2 (comprimento de onda de 10,6 nm por 15 segundos) e, no terceiro grupo, a superfície foi tratada com jateamento (250 µm Al2O3). Todas as amostras foram expostas à termociclagem, em seguida o teste de microinfiltração foi realizado medindo-se a profundidade de penetração do corante entre o soft liner e o disco de acrílico em microscópio digital. Os dados foram analisados estatisticamente por One-way ANOVA e testes post-hoc de Tukey. Além disso, o teste t foi usado para comparação entre dois grupos (P-valor ≤ 0,05). Resultados: Os valores médios máximos de microinfiltração foram observados no grupo não tratado (controle) seguido pelo grupo tratado com laser de CO2 e o valor médio mínimo de microinfiltração foi relacionado ao terceiro grupo para ambos os grupos não autoclavado e autoclavado com diferenças significativas entre eles. Além disso, dependendo do uso de autoclave, não houve significância em todos os grupos estudados. Conclusão: Houve diminuição da microinfiltração quando a superfície foi tratada com laser de CO2e jateamento. O uso de autoclave não alterou a microinfiltração entre o soft liner e a base da prótese (AU)

Does Sterilization Affect the Push Out Bond Strength of Experimental Dentin Posts? / ¿Afecta la esterilización la fuerza de adherencia de los postes de dentina experimentales?

ABSTRACT The purpose of this preliminary study is to evaluate the push-out bond strength (PBS) of experimental dentin posts (EDPs) obtained from human and bovine teeth sterilized by autoclaving and gamma radiation. Eighty-four mandibulary premolars were obturated and divided into three post groups: the glass fiber group (Fb) human EDP group (Hm) and the bovine EDP group (Bv). Three subgroups (n=12) were obtained for each EDP groups according to the sterilization methods; no sterilization (Cnt), steam autoclaving (Aut), and gamma radiation (Rad) a total dose of 25 kGy. All posts were cemented to root canals using a dual cured resin cement (Panavia SA). After the micro slices (1mm in thickness) were obtained of each subgroup, PBS test was performed. Data were analyzed using two-way ANOVA and Tukey's multiple comparison tests (α=.05). The post type and sterilization method was significantly effective on the PBS values according to the ANOVA (P<.001). No sterilization apllied EDP groups showed significantly higher PBS values than the sterilized groups (P<.001). Bv_Cnt (9.42 ±1.31) showed significantly lower PBS values than both Fb (12.36 ±1.54) and Hm_Cnt (11.06 ±1.38) groups (P<.001). Both steam autoclaving and gamma radiation affect the PBS values and fracture modes of EDPs negatively. The bovine EDPs are not as effective as human EDPs with regard to the PBS to the root dentin.

RESUMEN El propósito de este estudio preliminar es evaluar el push-out bond strength de los postes de dentina experimentales (PDE) obtenidos de dientes humanos y bovinos esterilizados por autoclave y radiación gamma. Ochenta y cuatro premolares mandibulares fueron obturadores y se dividieron en tres grupos experimentales de postes: el grupo de fibra de vidrio (Fb) grupo PDE humano (Hm) y el grupo PDE bovino (Bv). Se obtuvieron tres subgrupos (n=12) para cada grupo de PDE según los métodos de esterilización; sin esterilización (Cnt), autoclave a vapor (Aut) y radiación gamma (Rad) con una dosis total de 25 kGy. Todos los postes se cementaron a los conductos radiculares utilizando un cemento de resina de curado doble (Panavia SA). Después de que se obtuvieron las micro rebanadas (1 mm de espesor) de cada subgrupo, se realizó una prueba de push-out bond strength. Los datos se analizaron utilizando ANOVA de dos vías y las pruebas de comparación múltiple de Tukey (α=.05). El tipo de poste y el método de esterilización fueron significativamente efectivos en los valores de push-out bond strength según el ANOVA (P <.001). Los grupos de PDE no aplicados a la esterilización mostraron valores de push-out bond strength significativamente mayores que los grupos esterilizados (p <0,001). Bv_Cnt (9.42 ±1.31) mostró valores de push-out bond strength significativamente más bajos que los grupos Fb (12.36 ±1.54) y Hm_Cnt (11.06 ±1.38) (P <.001). Tanto el autoclave al vapor como la radiación gamma afectan negativamente los valores de push-out bond strength y los modos de fractura de los PDE. Los PDE bovinos no son tan efectivos como los PDE humanos con respecto a la fuerza de adhesión a la dentina de la raíz.

Impact of sealing method and layer number of autoclave bag on autoclave sterilization effect in the BSL-3 laboratory / 中华实验和临床病毒学杂志

Objective@#To evaluate, the method of different packing layer and sealing mode for the packaging of the infectious wastes in order to achieve better autoclave sterilization effect.@*Methods@#In the autoclave cycles P4 and P9, different packing layer (single, double and triple) and sealing mode (slightly folded, autoclave tape, nylon tape closure) were applied to the internal infectious waste sterilization, biological indicators were used to detect the effect of autoclave sterilization of the upper, middle and lower layers, respectively.@*Results@#1) In the autoclave cycle P4, the triple autoclave bags packaging sealing method was based on the slight folding, autoclave tape, and nylon taple, the biological indicator negative rate of the internal infectious waste in the upper layer, the middle layer and the lower layer were respectively in the upper layer 100%, 0%, 0%, in the middle layer 67%, 20%, 0%, and in the lower layer was 0%. The double autoclave bags packaging sealing method was based on the slight folding, autoclave tape, and nylon taple, the biological indicator negative rate of the internal infectious waste in the upper layer, the middle layer and the lower layer were respectively the in the upper layer 100%, 85%, 0%, the middle layer 45%, 0%, 0%, and the lower layer 10%, 0%, 0%. the single autoclave bag packaging sealing method wa based on the slight folding, autoclave tape, and nylon taple, the biological indicator negative rate of the internal infectious waste in the upper, middle and lower layers were respectively the upper layer 100%, 100%, 0%, the middle layer 70%, 45%, 0%, and the lower layer 12.5%, 0%, 0%. (2) In the autoclave cycle P9, the triple autoclave bags packaging sealing method was based on the slight folding, autoclave tape, and nylon taple, the biological indicator negative rate of the internal infectious waste in the upper layer, middle and lower layers were respectively the upper layer all 100%, the middle layer 100%, 100%, 70%, and the lower layer 100%, 100%, 30%. The double autoclave bags packaging sealing method was based on the slight folding, autoclave tape, and nylon taple, the biological indicator negative rate of the internal infectious waste in the upper, middle and lower layers were respectively the upper layer all 100%, the middle layer all 100% and the lower layer is 100%, 100%, and 60%. The single autoclave bag packaging sealing method was based on the slight folding, autoclave tape, and nylon taple, the biological indicator negative rate of the internal infectious waste in the upper, middle and lower layers were all 100%.@*Conclusions@#When autoclave is recommended for sterilization of infectious waste, the best effect was achieved with a single unsealed autoclave bag. If it is necessary to seal, the autoclave bag should not be completely sealed, avoiding incomplete penetration of steam into the interior space, otherwise the infectious waste can not be completely sterilized.

Eficacia da descontaminacao de residuos biologicos infectantes de laboratorios de microbiologia apos tratamento termico por autoclavacao / Efficacy of the decontamination of biological infectious waste after thermal treatment by autoclaving

A pesquisa foi realizada no Laboratório Central de Saúde Pública de Minas Gerais com o objetivo de validar o processo de descontaminação de resíduos infectantes do subgrupo A1 e identificar possíveis falhas no procedimento preliminar à sua disposição final. Foram avaliados tanto a descontaminação dos resíduos totalmente descartáveis acondicionados em sacos plásticos termorresistentes quanto o processo de descontaminação dos resíduos reutilizáveis provenientes do Laboratório de Tuberculose, acondicionados em caixas metálicas. Enquanto os resultados obtidos no primeiro estudo indicaram uma deficiência considerável no tratamento dos resíduos, no segundo caso a eficácia foi comprovada. Medidas preventivas e corretivas foram propostas e adotadas como consequência deste trabalho, e são aqui descritas.

Laboratory studies were performed at the Central Laboratory of Public Health of Minas Gerais in order to validate the process of infectious waste decontamination (subgroup A1) from the public health service and identify possible flaws in the procedure preliminary to its final disposal. We evaluated both the decontamination of disposable waste packed in thermo-resistant plastic bags as well and the decontamination process of reusable waste from the Tuberculosis Laboratory packed in metallic boxes. The results of the first study indicated a significant deficiency in waste treatment, while in the second case efficacy was demonstrated. Preventive and corrective measures were proposed and adopted as a result of this work and are described herein.

Infection control of light curing units / 대한치과보존학회지

When curing the composite restorations with light curing units, the light guides are often in direct contact with oral tissues, therefore contamination of light guides is inevitable. Curing light guides fall into the "semicritical" instrument category according to the Centers for Disease Control and Prevention (CDC) and must be heat or vapor-sterilized or at a minimum, these semicritical instruments must be sterilized in a liquid chemical agent. Currently, most common methods of maintaining sterility of the light guides are wiping the guide with a disinfectant, such as glutaraldehyde, after each patient use; using autoclavable guides; using presterilized, single-use plastic guides; and using translucent disposable barriers to cover the guide.

Avaliação da esterilização em autoclaves odontológicas através do monitoramento biológico / Evaluation of dental autoclave sterilization through biological monitoring

O objetivo deste estudo foi avaliar a ocorrência de esterilização em autoclaves de consultórios odontológicos, mediante o emprego de indicadores biológicos, assim como, através de questionário, conhecer a prática clínica do processamento do instrumental contaminado. Foram introduzidos em 40 autoclaves, juntamente como instrumental, três indicadores biológicos (próximo ao filtro, no centro e junto à porta). Após, os indicadores (testes e controle) foram incubados por 48 horas, para aferição do meio de cultura. Os indicadores-teste apresentaram mudança da cor do meio de cultura de roxo para amarelo em 14 (35%) das autoclaves, indicando ausência de esterilização. A maioria dos cirurgiões-dentistas (CDs) associa ao calor úmido, outros métodos de esterilização, como o químico e o calor seco. Nenhum cirurgião-dentista emprega rotineiramente o monitoramento biológico em seu consultório. Dos 31 cirurgiões-dentistas (77,5%) que empregam o controle físico e/ou químico da esterilização, apenas 74,2% dos mesmos, o fazem a cada ciclo. A grande maioria dos cirurgiões-dentistas (75%) emprega o envelope para o empacotamento do instrumental. No entanto, 77,5% dos mesmos não escrevem na embalagem a data da esterilização. Concluiu-se que 35% das autoclaves analisadas não estão realizando o processo de esterilização do instrumental e que algumas falhas durante o processamento do instrumental contaminado ainda existem e deveriam ser corrigidas.

The aim of this study was to evaluate the occurrence of autoclave sterilization at dental offices by means of biological indicators and questionnaires, as well as to know the clinical practice of processing the contaminated instruments. Three biological indicators (close to the filter, at the center and close to the door) were introduced into 40 autoclaves along with instruments. Next, indicators (test and control) were incubated for 48 hours in order to check the culture medium. The test-indicators had a change in the color of the culture medium from purple to yellow in 14 (35%) of autoclaves. Most dental surgeons (DS) associate other sterilization methods, such as chemical and dry heat, with damp heat. No Dental Surgeon routinely use biological monitoring at their offices. From the 31 Dental Surgeons (77.5%) who use physical and/or chemical control of sterilization, only 74.2% do it every cycle. The great majority of DS (75%) use the envelope for packing instruments. However, 77.5% of them do not write the sterilization date on the package. It was concluded that 35% of the analyzed autoclaves did not perform the instrument sterilization process and that some flaws during processing of the contaminated instruments still occur and should be corrected.

Cyclic fatigue of the sodium hypochlorite treated and/or steam autoclaved nickel-titanium endodontic files / 대한치과보존학회지

The purpose of this study was to determine the effect of sodium hypochlorite and steam autoclaving on the cyclic fatigue of nickel-titanium endodontic files. Two types of files with a .06 taper and #30 were used, K3(R) (SybronEndo, Glendora, California, USA) and Hero642(R) (Micro-Mega, Besancon, France). The files were divided into 6 experimental groups containing 10 files each group depending the soaking time in 6% sodium hypochlorite solution and number of cycles of steam autoclave. After sterilization, a cyclic fatigue test was performed on each file, and the fracture time was recorded in seconds. The control group underwent the cyclic fatigue test only. After the test, the surface characteristics of the files were observed using scanning electron microscopy (SEM). All groups containing the Hero 642(R) files showed a similar cyclic fatigue fracture time. However, the cyclic fatigue fracture time with the K3(R) files was significantly shorter in groups which were treated with sodium hypochlorite than in the control group (P < 0.05). SEM revealed both Hero642(R) and K3(R) files to have significant corrosion on the file surface in groups treated with sodium hypochlorite, compared with the sharp and regular blades of the control group. K3(R) files showed more corrosion than the Hero642(R) files. Bluntness of the blades of the K3(R) file was observed in groups treated with steam autoclave. Although there was no obvious destruction on the surface of steam autoclaved Hero642(R) files, slight bluntness was observed. Sterilizing with a steam autoclave is much less destructive to K3(R) files than sodium hypochlorite. The longer time exposed to sodium hypochlorite, the more destructive pattern was shown on the blades of the files. Therefore, when using sodium hypochlorite solution, the exposure time should be as short as possible in order to prevent corrosion and increase the cyclic fatigue fracture time.

The effect of autoclave sterilization and reuse of Smartpeg(TM) on the implant stability quotient (ISQ) measurement / 대한치과보철학회지

STATEMENT OF PROBLEM: Resonance frequency analysis is evaluated as the non-invasive and objective method for the evaluation of implant stability and has been increasingly used. It is necessary to evaluate the factors affect the ISQ measurement stability. PURPOSE: This study was performed to evaluate the effect of the autoclave sterilization and reuse of Smartpeg(TM) on ISQ measurement. MATERIAL AND METHODs: SmartPeg(TM) (Integration Diagnostics Ltd., Goteborg, Sweden) of autoclave group (A) was autoclave sterilized 9 times and Smartpeg(TM) of reuse group (R) was reused 9 times. Ten SmartPeg(TM)s were allocated to each group and after each autoclave sterilization and reuse, implant stability quotient (ISQ) values were measured 3 times from the two directions a and b at a right angle. Osstell(TM) mentor (Integration Diagnostics Ltd., Goteborg, Sweden) was used and type 1 (article no. 100353) Smartpeg(TM) was selected according to SmartpegTM reference list. Osstem Implant US II fixture (Osstem Co., Seoul, Korea) in 4.0 mm x 11.5 mm was embedded in the self-curing acrylic resin (Orthojet(R), Lang Dental, U.S.A.). Data was statistically analyzed by one-way ANOVA (alpha= .05) and scheffe test was done where a significant difference exist. Correlation test was also done between ISQ value and the number of autoclave sterilization or reuse. RESULTS: 1. In autoclave group, the means and sd. of ISQ value before autoclave sterilization were 84.97 +/-0.41, 84.93+/-0.74 at direction a and b. There was significant differences between autoclave groups at direction a and b (P=.000). 2. In reuse group, the means and sd. of ISQ value before reuse were 85.40+/-0.62, 85.50+/-0.57 at direction a and b. There was no significant difference between reuse groups at direction a and b (P>.05). 3. There was a weak positive correlation between the number of reuse and ISQ value at direction a and b (gamma=.207 and .246, P<.01). CONCLUSION: Within the limitations of this study, the following CONCLUSIONs were drawn. Till ninth reuse of Smartpeg(TM), the ISQ measurement stability did not be affected. After twice autoclave sterilization of Smartpeg(TM), the ISQ measurement stability was affected.

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.

The effect of heat sterilization on the surface topography and the tensile properties in various nickel titanium wires including a Korean product / 대한치과교정학회지

The purpose of this study is to investigate the changes of mechanical properties and surface topography of various nickel titanium wires after heat sterilization for recycling with quantitative method. The materials used were four kinds of nickel titanium orthodontic wires including a Korean product. Experimental specimens were treated with two kinds of heat sterilization methods; dry heat (180degrees C, 60snin) and autoclave (121degrees C, 15-20psi, 30min). Mechanical properties were evaluated by tensile test with Instron 4466 (load cell capacity : 1000 kg, cross head speed : 5mm/min, grip distance : 40mm, in room temperature). Surface topography of various wires was compared with each other qualitatively by using scanning electron microscopy and quantitatively by using profilometer. The findings were analyzed statistically with student t-tests. The results were as follows; 1. Neither method of heat sterilization hod any effects on tensile properties of the nickel-titanium wires used in this experiment. 2. Before heat sterilization, the surface smoothness was highest in Optimalloy, followed by Align and Sentailoy, with NiTi showing the lowest smoothness value. 3. In surface topography, Align and Optimalloy were not influenced by heat sterilization. NiTi, on the other hand, had increased roughness after dry heat sterilization and Sentalloy showed the same tendency after each of the two heat sterilization procedures.

Reconstruction of Large Bone Defect after Bone and Soft Tissue Tumor Resection , using Jeat / 대한정형외과학회잡지

To fill the large bone defect after bone and soft tissue tumor resection, there are several options such as tumor prosthesis, bone cement with intramedullary nail, autogenous bone graft and allograft. We had used isotrophic autogenous bone graft by using the heat-treated bone removed from tumor site. We analyzed the periods for junctional union and regeneration of autoclaved or low-heat treated groups, and compared these two methods to know which method is better for reconstruction of the bone defect after tumor resection. From Jan. 1987 to Sept. 1993, twelve patients took heat-treated autogenous bone graft: 6 auto- claved, and 6 low heat-treated. Each group had 10 places of junction sites between host and grafted bone. The tumors were 2 cases of osteosarcoma, 3 parosteal osteosarcoma, 2 Ewing's sarcoma, 2 malignant soft tissue tumors, 1 giant cell tumor, and 2 metastases from thyroid cancer and synovial sarcoma. The graft sites were 4 in humerus, 4 pelvis and 4 femur. Two cases showed marginal surgical margin and others wide surgical margin. Here we compare4 the difference between autoclaved group(120℃, 2 atm., 20 min) and low heat-treated group(65℃, 30 min. in water) on the aspect of complications and period to achieve junctional union to host bone. Average follow-up period was 25.3(11 to 88) months. Graft related complications in autoclaved group were bone resorption(2 sites), fracture of grafted bone(2). For low heat-treated group there was no such complication. Nonunion occurred in 3 sites for autoclaved group and 1 for low heat-treated group. Average period for junctional union was 7.3 months(5 to 10 months) for autoclaved group and 6.1 months(5 to 9 months) for low heat-treated group. With these results, heat treated bone autograft may have several advantages such as easy accessi- bility, low cost and anatomical reconstruction of the bone defect. The low heat-treated autogenous bone graft may have more advantages than that of the autoclaved one, and this method may be ratio- nalized to fill the large bone defect made by tumor resection.

Disinfecting Effect of Electrolyzed-oxidizing Water on Dental Instruments:A Disscusion / 中华医院感染学杂志

OBJECTIVE To evaluate the disinfecting effect of electrolyzed-oxiding water(EOW) on dental(instruments) contaminated after clinical operation.METHODS Use K-reamer and high-speed handpiece as objects of test.(K-reamers) were disinfected by EOW and 2% glutaraldehyde for 5min and 10min,respectively.And(handpieces) were disinfected by EOW and autoclave sterilization,respectively.The samples were collected from each(K-reamer) and each handpiece′surface and its water-canal before and after disinfection.The samples were done germiculture.RESULTS Disinfecting K-reamer for 10min,the disinfection rate of two disinfectants(EOW and 2%(glutaraldehyde)) were both 100%.Disinfecting handpiece with EOW(by surface-wiping,immersing and rinsing the water-canal)or autoclaving sterilization,the disinfection rate of EOW and 2%glutaraldehyde were both 100%.(Disinfecting) handpiece with EOW(by surface-wiping,immersing and rinsing the water-canal) or autoclaving(sterilizaion),the bacteria contaminated on handpiece′s surface and in the water-canal could all be killed,while(disinfecting) handpieces with EOW only by surface-wiping,and immersing,in the water-canal there were still a lot of bacteria.CONCLUSIONS The disinfecting effect of EOW is reliable and safe compared with 2%(glutaraldehyde) and autoclave sterilization.

Discussion on Compulsory Matching Security Equipment of Biosafety Laboratory / 医疗卫生装备

The construction of biosafety laboratory was highly concerned these years because of the spread of high pathogenic diseases including SARS and avian influenza. In the past several years, the construction of many BSL-2/3 laboratories played an important role in preventing the dissemination of pathogens involved in the research. Meanwhile, serious problems were also raised because some project designers or constructors were not clear with the compulsory safety equipments in these laboratories so that the requirement of zero-leakage could not be achieved. The compulsory safety equipments emerging and disposing solid, liquid and gas offal in the biosafety laboratory were reviewed. The R&D of special equipments in biosafety laboratory in China was also introduced.

THE TEMPERATURE-PRESSURE RELATIONSHIP OF MIXED GASES IN THE AUTOCLAVE / 微生物学通报

The temperature pressure relationship of mixed gases in the autoclave was analyzed with Clausius Clapeyron equation, Boyle's law and Dalton's law of partial pressure Antoine equations discribing the P T relationship inside the autoclave with different residual air were built up according to data published and a method calculating the temperature from values of manometer was introduced The necessity to efflux the air from the autoclave was explained theoretically

Sterilization and preservation in oriental medicine part (1) On oriental needles / 全日本鍼灸学会雑誌

In daily clinic, we are greatly concerned with the sterilization of oriental needles and appliances.<br>Staphylococcus epidermitis and aureus, bacillus subtilis and pseudomonas aeruginosa and so on were detected when we cultivated bacteria on daily oriental needles in our clinical office. The author intestigated the ability of six sterilization methods; (1) ultra violet (253.7nm) 10 minutes, (2) wiping out by medical raw cotten contained water, (3) wiping out by medical raw cotten contained isopropylalcohol 70%, (4) dipping in isopropylalcohol 10 minutes, (5) dipping in 0.5% Hibitane (chlorhexidine) alcohol 10 minutes, (6) autoclave.<br>Among these six methods, the autoclave method is excellent of course, but among the simpler methods, the following one is excellent; after having wiping out oriental needles a few times by medical raw cotton contained 70% isopropylalcohol or 0.5% chlorhexidine, dipping in 0.5% chlorhexidine alcohol 10 minutes.<br>It is not necessary for this method to use machines, electricity, gas or over 30 minutes: it is enough to dip chlorhexidine for 10 minutes.

The influence of autoclave sterilization on elastic module and flexural strength of five types of posts / 西安交通大学学报(医学版)

Objective To research the influence of autoclave sterilization on elastic module and flexural strength of five types of posts.Methods Shidelong carbon,glass and quartz fiber post,tenax glass fiber post and Anthogyr titanium post were chosen,and all the samples were divided into two groups which included five subgroups according to the model of posts,each subgroup including six samples.Experimental groups were autoclave sterilized(50 min at 134℃ and 2.2MPa),While the control groups were not.With three point loading system,elastic module and flexural strength of all the samples were measured.Results were statistically analyzed to find the difference between them.Results There was no statistical difference between Shidelong carbon,glass,quartz fiber post and Tenax glass fiber post in elastic module and flexural strength in both experimental group and control group,while Anthogyr titanium post gained the highest elastic module and flexural strength.Paired-samples t test also showed there was no statistical difference between experimental group and control group in elastic module and flexural strength.Conclusion Fiber posts perfectly meet the need of clinical use on flexural strength.Furthermore,with elastic module similar to dentin and much lower than metal posts,fiber posts will help to protect the remaining tooth structure from fracture.Autoclave sterilization has a little influence on elastic module and flexural strength of posts,which allows practitioners to systematically sterilize the posts in clinic.