Post sterilization of intraoral scan body and the effect it has on the axes and distances between three adjacent implants: in-vitro study.

BACKGROUND: The purpose of this pilot in-vitro study was to assess the effect of sterilization on the intra-implant axis, inter-implant axis, intra-implant distance and inter-implant distance of three implants in a straight line by using laboratory scanner (LBS) versus intra-oral scanner (IOS) with intra-oral scan bodies (ISB). METHODS: A printed 3D model with three internal hex analogs in the positions 15#,16#,17# was used. Zirkonzhan (ZZ) intra-oral scan body (ISB), two-piece titanium was used. The ZZ ISBs were scanned by 7 Series dental wings (LBS) and 30 times by Primescan (IOS) pre sterilization and 30 times post sterilization. For each scan (pre and post) stereolithography (STL) file was created and a comparison between all the scans pre sterilization and post sterilization were superimposed on the laboratory scan by using a 3D analyzing software. A Kolmogorov-Smirnov test performed followed by Wilcoxon Signed Ranks tests. (p < 0.05) Results: Post sterilization of the ZZ ISB, the mean errors were significantly increased for the inter-implant distances (p < 0.0005), intra-implant distances 1,2,3 (p < 0.0005), intra-implant axis 1,3 (p < 0.0005) and inter-implant axes 13,23 (p < 0.05). In contrast, the mean errors for intra-implant axis 2 (p < 0.0005) and inter-implant axis 12 (p < 0.0005) were significantly reduced. CONCLUSIONS: ZZ ISB showed changes in all four parameters after sterilization. The middle ISB had the largest changes in mean error regarding all four parameters. Sterilization process may affect the three-dimensional (3D) structure of the ZZ ISB after three cycles. There is a lack in the literature in this field and there is a need for further studies to explore the effect of sterilization (multiple cycles) on different ISBs and for creating an approved guidelines regarding the amount of sterilization for each ISB in the industry.

High Performance Organic Mixed Ionic-electronic Polymeric Conductor with Stability to Autoclave Sterilization.

We present a series of newly developed donor-acceptor (D-A) polymers designed specifically for organic electrochemical transistors (OECTs) synthesized by a straightforward route. All polymers exhibited accumulation mode behavior in OECT devices, and tuning of the donor comonomer resulted in a three-order-of-magnitude increase in transconductance. The best polymer gFBT-g2T, exhibited normalized peak transconductance (gm,norm) of 298±10.4 S cm-1 with a corresponding product of charge-carrier mobility and volumetric capacitance, µC*, of 847 F V-1 cm-1 s-1 and a µ of 5.76 cm2 V-1 s-1, amongst the highest reported to date. Furthermore, gFBT-g2T exhibited exceptional temperature stability, maintaining the outstanding electrochemical performance even after undergoing a standard (autoclave) high pressure steam sterilization procedure. Steam treatment was also found to promote film porosity, with the formation of circular 200 - 400 nm voids. These results demonstrate the potential of gFBT-g2T in p-type accumulation mode OECTs, and pave the way for the use in implantable bioelectronics for medical applications.

Thermal pretreatment of Lantana camara for improved biogas production: Process parameter studies for energy evaluation.

The rigid lignocellulosic structure of Lantana camara impedes the hydrolysis phase and reduces the biogas production during anaerobic digestion of Lantana camara. Hence, the current study focuses on the impact of various heating pretreatment techniques, viz., hot air oven (HAO), autoclave (ATC), hot water bath (HWB), and microwave (MCW) on L. camara to speed up hydrolysis and boost up biogas production. ATC pretreatment of L. camara was witnessed to be most efficient compared to HAO, MCW, and HWB pretreatment. ATC pretreatment enhanced the solubilization (45.44%), and an increment in volatile fatty acids (VFA) was observed (56.75%) at 110 °C for 80 min when correlated to the untreated (control). Cumulative methane production following ATC pretreatment had risen to 3656 mL in 5 weeks from 2895 mL in 7 weeks. Thermal pretreatment of Lantana camara broke down the rigid lignocellulosic structure, accelerating the hydrolysis stage and improving biogas production simultaneously. To the best of our knowledge, this is the first thermal pretreatment study conducted on Lantana camara for biogas production.

Does repeated autoclave sterilization cause changes in the color and fragility of fiberglass reinforced resin crowns?

BACKGROUND: Since the effects of sterilization on the Fiberglass Reinforced Resin Crowns (FRRCs) is not well-known the aim of current study was to evaluate the effects of autoclave sterilization on the fracture resistance, color stability, and surface composition of FRRCs. METHODS: A total of 48 crowns were used. The crowns were divided into three groups according to the sterilization number: no sterilization (Control Group), one sterilization (Group 1), and four sterilizations (Group 2). The microstructure of the three crowns from each group was evaluated using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy. Thirteen FRRCs from each group were first used for color stability testing and then for the fracture resistance analysis. One-way analysis of variance (ANOVA), one-way repeated measures ANOVA, and paired t-tests were used in the statistical analysis. RESULTS: EDX results revealed that the weight% of surface silicon atoms in group 2 was significantly higher. Some crack lines could be observed on the SEM images. Statistically significant differences were found in color stability following the first and fourth sterilization cycles (p < .01). The increase in the sterilization cycle did not statistically decrease the fracture resistance of the FRRCs (p = .055); however, overall, a decreasing trend was observed in fracture resistance as the sterilization cycle increased. CONCLUSIONS: Autoclave sterilization caused some changes in the surface elemental composition and surface morphology of FRRCs. Avoiding unnecessary FRRC trials is important to reduce the number of sterilizations.

Environmental risks of antibiotic resistance genes released from biological laboratories and its control measure.

Antibiotic resistance genes (ARGs) are a growing global threat to public health. Biological laboratory wastewater contains large amounts of free ARGs. It is important to assess the risk of free ARGs from biological laboratories and to find appropriate treatments to control their spread. The fate of plasmids in the environment and the effect of different thermal treatments on their persistence activity were tested. The results showed that untreated resistance plasmids could exist in water for more than 24 h (the special 245 bp fragment). Gel electrophoresis and transformation assays showed that the plasmids boiled for 20 min retained 3.65% ± 0.31% transformation activity of the intact plasmids, while autoclaving for 20 min at 121 °C could effectively degrade the plasmids and that NaCl, bovine serum albumin, and EDTA-2Na affected the degradation efficiency of the plasmids during boiling. In the simulated aquatic system, using 106 copy/µL of plasmids after autoclaving, only 102 copies/µL of the fragment after only 1-2 h could be detected. By contrast, boiled plasmids for 20 min were still detectable after plunging them into water for 24 h. These findings suggest that untreated and boiled plasmids can remain in the aquatic environment for a certain time resulting in the risk of disseminating ARGs. However, autoclaving is an effective way of degrading waste free resistance plasmids.

Evaluation of a Rapid Biological Spore Test for Dental Instrument Sterilization.

AIM: This study evaluated the reliability of a new rapid biological spore test (BST) for determining the sterilization efficacy of dental steam autoclaves within 20 minutes, as compared to a conventional BST requiring 2 days of incubation after autoclave exposure. MATERIALS AND METHODS: A total of 177 pairs of BST, each composed of a rapid test (Celerity™ 20 Steam Biologic Indicator, Steris) and a conventional BST (Attest™ 1262 Biological Indicator, 3M), both containing Geobacillus stearothermophilus spores, were placed into steam autoclaves loaded with instruments, and subjected to either sterilizing (157 pairs) or non-sterilizing conditions (20 pairs). Celerity™ BST was then incubated for 20 minutes at 57°C, with the growth medium evaluated spectrophotometrically for fluorescent α-glucosidase signal changes (no change with successful sterilization; increased fluorescence after failed sterilization). Attest™ BST was incubated for 48 hours at 57°C, after which a pH-based color change in the culture broth was visually assessed (no change in purple color with successful sterilization; change to yellow color with failed sterilization). RESULTS: Celerity™ and Attest™ BST both accurately identified successful sterilization, with no G. stearothermophilus spore growth from either BST after exposure to sterilizing steam autoclave conditions (100% agreement between 157 pairs of each BST). Both BST also accurately detected unsuccessful sterilization, with all tested ampoules positive for G. stearothermophilus spore germination after non-sterilizing steam autoclave time periods. Both BST exhibited 100% sensitivity, specificity, and accuracy for detection of sterilizing steam autoclave conditions. CONCLUSION: Celerity™ BST, after only 20 minutes incubation, performed equally as well as a BST requiring 48 hours incubation in determining the sterilization efficacy of dental steam autoclaves. CLINICAL SIGNIFICANCE: Rapid BST offer earlier detection of sterilization failure before potentially contaminated dental instruments are used in clinical patient care.

Capacity assessment and implementation analysis of common treatment facility for the management of infectious healthcare waste in rapidly urbanising city of Nepal.

This study is one of the first systematic attempts to examine the possibility of a common treatment facility (CTF) to treat infectious healthcare waste (HCW) in Nepal. First, the survey was conducted in 14 healthcare facilities (HFs) ranging from health posts to large hospitals selected from 120 total HFs in Nepalgunj sub-metropolitan city (SMC), a rapidly urbanising city of Nepal to investigate the current practices of HCW management (HCWM) and to estimate the waste generation and characteristics in the different HFs. The result shows that the average unit waste generation rate for health posts, clinics, urban health centres, and hospitals was estimated at 1.397 kg day-1, 1.608 kg day-1, 0.178 kg day-1 and 1.818 kg bed-1 day-1, respectively. Of the total 1242 kg day-1 HCW generated in Nepalgunj SMC, 73% is infected in the current situation, but if fully sorted at source, only 32% of the waste will be infected. Based on these HCW generation data and fraction of infectious waste, including waste management practices, three different scenarios are proposed for the capacity assessment and designing implementation modality of the CTF to treat infectious waste from all HFs of Nepalgunj SMC as a case study where an integrated solid waste management facility including material recovery facility and sanitary landfill site for municipal solid waste management is already in operation. The different implementation analyses are discussed, and the best implementation arrangement has been recommended for the sustainability of the project. This approach can be replicated in other cities alone or regions with many neighbouring cities of Nepal and explores a workable solution for HCWM in the rapidly urbanising cities of developing countries to help them improve their condition.

Effect of high pressure heating on physical and chemical characteristics of Asian sea bass (Lates calcarifer) backbone.

Physical and chemical properties of Asian sea bass (Lates calcarifer) backbone subjected to high pressure heating (autoclaving, 121ºC) for different times (30 min; AT-30; 60 min; AT-60; 90 min; AT-90) were studied. As heating time augmented, the increases in protein, α-amino group and hydroxyproline contents in liquor were attained, while hardness was declined indicating that more organic compounds were leached out from the bone matrix. More pronounced XRD pattern was observed in backbone autoclaved for 90 min as a consequence of nano-hydroxyapatite crystals agglomeration. Extension of high-pressure heating time reduced the organic matters as elucidated by TGA and DTA data. Asian sea bass backbone heated at 121ºC for 90 min using autoclave had the lowered protein and lipid contents but increased ash content with highest calcium (29.65 ± 0.69%), phosphorus (15.80 ± 0.07%) and iron (15.10 ± 0.61 mg/kg) contents, compared to those with shorter heating time. Therefore, pre-heat treatment could reduce the organic compounds and decrease bone hardness for further process, especially for bio-calcium production.

Alteration and Stability of Complex Macromolecular Amino Acid Precursors in Hydrothermal Environments.

The early Solar System comprised a broad area of abiotically created organic compounds, including interstellar organics which were integrated into planetesimals and parent bodies of meteorites, and eventually delivered to the early Earth. In this study, we simulated interstellar complex organic compounds synthesized by proton irradiation of a gas mixture of CO, NH3, and H2O, which are known to release amino acids after acid hydrolysis on the basis of Kobayashi et al. (1999) who reported that at the first stage of chemical evolution, the main compounds formed abiotically are complex organic compounds with high molecular weights. We examined their possible hydrothermal alteration and stabilities as amino acid precursors under high temperature and pressure conditions simulating parent bodies of meteorites by using an autoclave. We reported that all samples treated at 200-300 °C predominantly released glycine and alanine, followed by α-aminobutyric acid, and serine. After heating, amino acid concentrations decreased in general; however, the recovery ratios of γ-aminobutyric acid increased with temperature. The interstellar complex organic analog could maintain as amino acid precursors after being treated at high temperature (200-300 °C) and pressure (8-14 MPa). However, the molecular structures were altered during heating to form organic compounds that are more stable and can survive in elevated hydrothermal conditions.

Effect of autoclave sterilization on cyclic fatigue and torsional fracture resistance of NiTi rotary instruments.

The purpose of this study is to assess the effect of autoclave sterilization on the cyclic fatigue and torsional fracture resistance of ProTaper Universal (PTU), K3XF, HyFlex EDM (EDM), and TF adaptive (TFA). Sixty instruments from each file type were divided into two categories for cyclic fatigue group (CGr) and torsional fracture group (TGr). CGr and TGr were divided into three subgroups, respectively, consisting of ten instruments from each file type. Cyclic fatigue fracture test was performed using artificial canal made of stainless steel, and the mean number of cycles to failure (NCF) were determined. CGr1, the files were tested to establish baseline for NCF; CGr2, the files were tested cyclic fatigue after 10 cycles of autoclave; CGr3, instruments were autoclaved after being cycled to 25, 50, and 75% of corresponding NCF determined in CGr1, followed by cyclic fatigue test. The torsional fracture test was performed without autoclave (TGr1), after 3-cycle autoclave (TGr2), and 7-cycle autoclave (TGr3), respectively, which evaluated maximum torque and angular deflection. NCF, maximum torque and angular deflection were compared using one-way ANOVA with Bonferroni test. Two-way ANOVA was performed to determine the interaction between 'autoclave treatment' and 'type of NiTi file'. EDM showed highest NCF within the same autoclave treatment. TFA presented the lowest maximum torque and the highest angular deflection, and PTU presented the lowest angular deflection. Within the same NiTi file systems, most of NCF, maximum torque and angular deflection of tested files were not significantly influenced by autoclave condition.

Pressureless and Low-Pressure Synthesis of Microporous Carbon Spheres Applied to CO2 Adsorption.

In this work, low-pressure synthesis of carbon spheres from resorcinol and formaldehyde using an autoclave is presented. The influence of reaction time and process temperature as well as the effect of potassium oxalate, an activator, on the morphology and CO2 adsorption properties was studied. The properties of materials produced at pressureless (atmospheric) conditions were compared with those synthesized under higher pressures. The results of this work show that enhanced pressure treatment is not necessary to produce high-quality carbon spheres, and the morphology and porosity of the spheres produced without an activation step at pressureless conditions are not significantly different from those obtained at higher pressures. In addition, CO2 uptake was not affected by elevated pressure synthesis. It was also demonstrated that addition of the activator (potassium oxalate) had much more effect on key properties than the applied pressure treatment. The use of potassium oxalate as an activator caused non-uniform size distribution of spherical particles. Simultaneously higher values of surface area and total pore volumes were reached. A pressure treatment of the carbon materials in the autoclave significantly enhanced the CO2 uptake at 25 °C, but had no effect on it at 0 °C.

Extraction of Protein from Four Different Seaweeds Using Three Different Physical Pre-Treatment Strategies.

Seaweeds are a rich source of protein and can contain up to 47% on the dry weight basis. It is challenging to extract proteins from the raw biomass of seaweed due to resilient cell-wall complexes. Four species of macroalgae were used in this study-two brown, Fucus vesiculosus and Alaria esculenta, and two red, Palmaria palmata and Chondrus crispus. Three treatments were applied individually to the macroalgal species: (I) high-pressure processing (HPP); (II) laboratory autoclave processing and (III) a classical sonication and salting out method. The protein, ash and lipid contents of the resulting extracts were estimated. Yields of protein recovered ranged from 3.2% for Fucus vesiculosus pre-treated with high pressure processing to 28.9% protein recovered for Chondrus crispus treated with the classical method. The yields of protein recovered using the classical, HPP and autoclave pre-treatments applied to Fucus vesiculosus were 35.1, 23.7% and 24.3%, respectively; yields from Alaria esculenta were 18.2%, 15.0% and 17.1% respectively; yields from Palmaria palmata were 12.5%, 14.9% and 21.5% respectively, and finally, yields from Chondrus crispus were 35.2%, 16.1% and 21.9%, respectively. These results demonstrate that while macroalgal proteins may be extracted using either physical or enzymatic methods, the specific extraction procedure should be tailored to individual species.

Rambutan (Nephelium lappaceum) kernel olein as a non-hydrogenated fat component for developing model non-dairy liquid creamer: effect of emulsifier concentration, sterilization, and pH.

In this work, the effects of the emulsifier concentration, sterilization process, and pH on the properties and stability of the model liquid creamer were evaluated. Applying diacetyl tartaric acid ester of mono- and diglycerides or DATEM at a concentration of 0.3% (w/w) in the presence of 2% (w/w) sodium caseinate produced stable model liquid creamers (10% (w/w) rambutan kernel olein) with a small particle size (Z-average ≈ 200 nm) and a narrow size distribution range (PDI < 0.24). These creamers were stable regarding creaming and coalescence, having non-flocculated particles and a constant flow behavior index (n) after sterilization using autoclaving (121 °C, 1.1 bar for 15 min) and during storage for 150 days at 25 °C. The model liquid creamers were unstable at pH values near the isoelectric point of caseinate (pH 4-5). However, these were stable after mixing with hot coffee solutions based on no observed feathering or sedimentation. The whitening performance of the model liquid creamers compared well with commercial ones. Non-hydrogenated fat-based model non-dairy liquid creamer was successfully formulated using rambutan kernel olein as a fat component. The results obtained in this study are useful for the possible application of fractionated rambutan kernel fat in food products.

Use of autoclave extraction and liquid chromatography with tandem mass spectrometry for determination of maleic hydrazide residues in tobacco.

Maleic hydrazide has been extensively used as an effective growth regulator in tobacco sucker control. After application, maleic hydrazide distributes itself throughout the tobacco plant where it can exist as free, or forms glucoside conjugates with glucose, or becomes bound with lignin. Among them, free maleic hydrazide and its glucoside conjugates are extractable under conventional solvent extraction, while lignin bound maleic hydrazide is claimed to be non-extractable. Herein, an autoclave extraction method has been developed to extract maleic hydrazide effectively, in which tobacco samples are extracted in an autoclave at 130°C for 1 h using 4 M hydrochloric acid. Under such pressurized hot acidic water conditions, lignin bound maleic hydrazide can be released. Meanwhile, glucoside conjugates are hydrolyzed. Total maleic hydrazide is detected by liquid chromatography coupled with tandem mass spectrometry, and the quantitative results coincide well with that obtained from the international standard method. The proposed autoclave extraction with liquid chromatography and tandem mass spectrometry method exhibits excellent linearity in the range of 5-200 mg/kg (R2  = 0.9998), the matrix matched limit of detection and limit of quantification is 0.68 and 2.27 mg/kg, respectively. This method is simple and improves sample capacity, providing an effective approach to monitoring maleic hydrazide residues in tobacco.

Comparative Effect of Different Polymerization Techniques on the Flexural and Surface Properties of Acrylic Denture Bases.

PURPOSE: Polymerization techniques have been modified to improve physical and mechanical properties of polymethylmethacrylate (PMMA) denture base, as have the laboratory procedures that facilitate denture construction techniques. The purpose of the present study was to investigate the effect of autoclave polymerization on flexural strength, elastic modulus, surface roughness, and the hardness of PMMA denture base resins. MATERIALS AND METHODS: Major Base and Vertex Implacryl heat-polymerized acrylic resins were used to fabricate 180 specimens. According to the polymerization technique, tested groups were divided into: group I (water-bath polymerization), group II (short autoclave polymerization cycle, 60°C for 30 minutes, then 130°C for 10 minutes), and group III (long autoclave polymerization cycle, 60°C for 30 minutes, then 130°C for 20 minutes). Each group was divided into two subgroups based on the materials used. Flexural strength and elastic modulus were determined by a three-point bending test. Surface roughness and hardness were evaluated with a profilometer and Vickers hardness (VH) test, respectively. One-way ANOVA and the Tukey-Kramer multiple-comparison test were used for results analysis, which were statistically significant at p ≤ 0.05. RESULTS: Autoclave polymerization showed a significant increase in flexural strength and hardness of the two resins (p < 0.05). The elastic modulus showed a significant increase in the major base resin, while a significant decrease was seen for Vertex Implacryl in all groups (p < 0.05); however, there was no significant difference in surface roughness between autoclave polymerization and water-bath polymerization (p > 0.05). CONCLUSION: Autoclave polymerization significantly increased the flexural properties and hardness of PMMA denture bases, while the surface roughness was within acceptable clinical limits. For a long autoclave polymerization cycle, it could be used as an alternative to water-bath polymerization.

Behavior of a Metal Organic Framework Thin-Film at Elevated Temperature and Pressure as Studied with an Autoclave-Inserted Atomic Force Microscope.

Bridging the gap in studying surface reactions, processes, and morphology and measuring at (catalytic) relevant conditions is crucial for our understanding of the working principles of porous crystalline materials. Scanning tunneling microscopy is limited because of the required conductivity of the sample, whereas atomic force microscopy (AFM) is often challenging in use owing to the physical mechanism underlying the technique. Herein, we report a tailor-made autoclave-inserted AFM, able to measure at ∼20 bar and ∼110 °C. First, we show the ability to obtain nanometer resolution on well-defined test samples at before-mentioned conditions. Second, to demonstrate the possibilities of analyzing morphological evolutions at elevated temperatures and pressures, we use this setup to measure the stability of a surface-anchored metal-organic framework (SURMOF) in-situ at pressures of 1-20 bar in the temperature range between 20 and 60 °C. It was found that the showcase HKUST-1 material has a good physical stability, as it is hardly damaged from exposure to pressures up to 20 bar. However, its thermal stability is weaker, as exposure to elevated T damaged the material by influencing the interaction between organic linker and metal cluster. In-situ measurements at elevated T also showed an increased mobility of the material when working at such conditions. Combining the strength of AFM at elevated T and p with ex-situ AFM and spectroscopic measurements on this MOF showcases an example of how porous materials can be studied at (industrially) relevant conditions using the autoclave-inserted AFM.

Effect of multiple autoclave cycles on the surface roughness of HyFlex CM and HyFlex EDM files: an atomic force microscopy study.

AIM: To compare the effect of autoclave cycles on the surface topography and roughness of HyFlex CM and HyFlex EDM instruments using atomic force microscopy (AFM) analysis. METHODOLOGY: Eight new files of each brand were subdivided into four subgroups (n = 2/each subgroup). One group was allocated as the control group and not subjected to autoclave sterilization. The other three groups were subjected to different numbers (1, 5, and 10) of autoclave sterilization cycles. After the cycle instruments were subjected to AFM analysis. Roughness average (Ra) and the root mean square (RMS) values were chosen to investigate the surface features of endodontic files. The data was analyzed using one-way ANOVA and post hoc Tamhane tests at 5% significant level. RESULTS: The lowest Ra and RMS values were observed in the HyFlex EDM files that served as the control and in those subjected to a single cycle of autoclave sterilization (P < 0.05). The highest Ra and RMS values were observed in the HyFlex CM and HyFlex EDM files that were subjected to 10 cycles of autoclave sterilization (P < 0.05). The surface roughness values of the HyFlex CM group showed a significant increase after ten autoclave cycles, whereas those of the HyFlex EDM group exhibited a significant change after five autoclave cycles (P < 0.05). CONCLUSIONS: Although the initial surface roughness values of the HyFlex EDM files were lower than those of the HyFlex CM files, the surface roughness values of the EDM files showed a statistically significant increase after 5 cycles of autoclave sterilization. In contrast, the surface roughness values of the HyFlex CM files did not increase until 10 cycles of autoclave sterilization. CLINICAL RELEVANCE: Present study indicated that autoclave sterilization negatively affected the surface roughness of the tested NiTi files.

Evaluation of Various Sterilization Processes of Orthodontic Instruments using Biological Indicators and Conventional Swab Test Method: A Comparative Study.

AIM: This study aimed to compare the efficiency of various sterilization procedures using conventional spore monitoring method, i.e., by using swab test and biological indicators and to determine the efficiency of cold sterilization by using Bioclenz-G (2% glutaraldehyde) solution. MATERIALS AND METHODS: Each group was divided into medium load (containing 15 sets of instruments) and heavy load (containing 30 sets of instruments). Each group was tested 15 times for medium and heavy loads. Two groups are swab tested control group and experimental group with three different methods of sterilization: hot air oven, cold sterilization, and ethylene dioxide sterilization. RESULTS: Spores were present in all the groups tested for 10 minutes cycle, in comparison with no spore growth in any of the groups tested for a 10-hour cycle. CONCLUSION: All methods of sterilization showed complete sterilization of instruments when monitored with biological indicators. One group of heavy load in steam autoclave and one group each of medium load and heavy load in hot air oven sterilizer showed sterilization failure when monitored with the conventional swab test method. CLINICAL SIGNIFICANCE: This study proves the efficacy and durability of various sterilization procedures.

Comparison of mechanical and dynamic mechanical behaviors of different dental resins polymerized by different polymerization techniques.

PURPOSE: The aim of the present investigation was to evaluate the effect of autoclave polymerization method on the mechanical and dynamic mechanical properties of different polymethylmethacrylate denture base materials. MATERIALS AND METHODS: Three different denture materials were used during the study, two of them were heat polymerizable denture base material (Meliodent and Paladent) and one was microwave polymerizable denture base material (Acron MC). Duncan test was used for the statistical analysis. Statistical analyses were completed using a two-way analysis of variance. Statistical analysis of test results was carried out with a 95% confidence level. RESULTS: Tensile strength was increased with autoclave polymerization regardless of the denture base material type. Paladent specimens with autoclave polymerization (30 min at 60°C and 10 min at 130°C) have the highest average impact strength value. Acron MC specimens have the highest average flexural strength and modulus. Flexural strength improved with autoclave polymerization for both of 10 and 20 min polymerizations for each of Meliodent and Paladent specimens. CONCLUSIONS: Autoclave polymerization provided higher polymerization temperatures compared with the conventional heat polymerization. Autoclave-polymerized acrylic resin specimens showed higher tensile strength values; however, this was not the case for the impact test results. Flexural strength of specimens was improved with autoclave polymerization. Glass transition temperature was increased with autoclave polymerization.

Validation of Autoclave Protocols for Successful Decontamination of Category A Medical Waste Generated from Care of Patients with Serious Communicable Diseases.

In response to the Ebola outbreak in 2014, many hospitals designated specific areas to care for patients with Ebola and other highly infectious diseases. The safe handling of category A infectious substances is a unique challenge in this environment. One solution is on-site waste treatment with a steam sterilizer or autoclave. The Johns Hopkins Hospital (JHH) installed two pass-through autoclaves in its biocontainment unit (BCU). The JHH BCU and The Johns Hopkins biosafety level 3 (BSL-3) clinical microbiology laboratory designed and validated waste-handling protocols with simulated patient trash to ensure adequate sterilization. The results of the validation process revealed that autoclave factory default settings are potentially ineffective for certain types of medical waste and highlighted the critical role of waste packaging in successful sterilization. The lessons learned from the JHH validation process can inform the design of waste management protocols to ensure effective treatment of highly infectious medical waste.