scholarly journals Peracetic Acid: A Practical Alternative to Formalin for Disinfection of Extracted Human Teeth

2021 ◽  
Vol 8 (12) ◽  
pp. 217
Author(s):  
Riaz Ali ◽  
Justin Bartholomew ◽  
Randolph Coffey ◽  
Caroline Carrico ◽  
Todd Kitten ◽  
...  
Keyword(s):  
Disease Control ◽  
Peracetic Acid ◽  
Brain Heart Infusion ◽  
Brain Heart Infusion Broth ◽  
Sterile Water ◽  
Anaerobic Conditions ◽  
Human Teeth ◽  
Materials Research ◽  
Amalgam Fillings

Extracted human teeth provide the closest approximation to teeth in situ and play important roles in dental education and materials research. Since extracted teeth are potentially infectious, the Centers for Disease Control recommend their sterilization by autoclaving or disinfection by formalin immersion to ensure safe handling. However, autoclaving is not recommended for teeth with amalgam fillings and formalin is hazardous. The goal of the present study was to investigate the potential of peracetic acid (PA) as an alternative method to achieve reliable disinfection of freshly extracted teeth. A total of 80 extracted teeth were collected for this study. Whole teeth were incubated in one of four solutions for defined periods of time: sterile water (2 weeks), formalin (2 weeks), PA 1000 ppm (2 weeks), and PA 2000 ppm (1 week). After sectioning, the crown and root fragments were transferred into separate tubes containing brain–heart infusion broth and incubated at 37 °C under anaerobic conditions for 72 h. Absence of broth turbidity was used to assess effectiveness of disinfection. No turbidity was observed in any of the formalin-treated or peracetic acid-treated samples, signifying complete disinfection. Our results indicate that PA can effectively disinfect extracted human teeth, providing a reliable alternative to formalin and autoclaving.

THE EFFECT OF "COMPETASE" ON DNA UPTAKE IN PROVOKED TRANSFORMATION OF A STREPTOCOCCUS

1965 ◽  
Vol 11 (5) ◽  
pp. 823-827 ◽  
Author(s):  
R. Pakula ◽  
A. H. W. Hauschild
Keyword(s):  
Deoxyribonucleic Acid ◽  
Brain Heart Infusion ◽  
Streptomycin Resistance ◽  
Brain Heart Infusion Broth ◽  
Dna Uptake ◽  
Retarding Effect ◽  
Competence Factor ◽  
Effect On Growth

The competence-provoking factor produced by the highly transformable group H streptococcus, strain Challis, was used to provoke efficient transformability in the poorly transformable group H streptococcus, strain Wicky. Transformations to streptomycin resistance were carried out with C14-labelled DNA which was extracted from bacteria fed with thymidine-2-C14.When cultures of strain Wicky were grown in Difco brain–heart infusion broth, supplemented with serum, and treated with competence factor and deoxyribonucleic acid, 25 to 40% of viable units were transformed while no transformation occurred without the factor. At the same time, the incorporation of C14 into cells treated with competence factor was higher than incorporation of C14 into untreated cells.Crude preparations of the competence factor had a retarding effect on growth of the streptococcus, irrespective of whether DNA was added.

Toxin Production by Psychrotrophic Bacillus spp. Present in Milk

1990 ◽  
Vol 53 (9) ◽  
pp. 790-792 ◽  
Author(s):  
M. W. GRIFFITHS
Keyword(s):  
Bacillus Cereus ◽  
Brain Heart Infusion ◽  
Bacterial Count ◽  
Toxin Production ◽  
Latex Agglutination ◽  
Brain Heart Infusion Broth ◽  
Agglutination Assay ◽  
Bacillus Spp ◽  
Latex Agglutination Assay

Using a reversed passive latex agglutination assay, about 85% of psychrotrophic Bacillus spp. tested were shown to produce diarrhoegenic toxin during growth on brain heart infusion broth at 25°C. The majority of these strains were identified as Bacillus cereus or cereus-related strains. However, a number of other species was capable of synthesizing the toxin. Further investigation of four psychrotrophic Bacilli showed that the toxin was produced during growth in milk at temperatures ranging from 6 to 21°C. Toxin production increased with increasing temperatures and was not synthesized in appreciable quantities until the bacterial count exceeded 1 × 107 cfu/ml.

In Situ Testing Using Synchrotron Radiation Computed Tomography in Materials Research

MRS Advances ◽  
2019 ◽  
Vol 4 (51-52) ◽  
pp. 2831-2841
Author(s):  
Xinchen Ni ◽  
Nathan K. Fritz ◽  
Brian L. Wardle
Keyword(s):  
Computed Tomography ◽  
Synchrotron Radiation ◽  
Three Dimensional ◽  
Lithium Ion ◽  
Time Lapse ◽  
In Situ Testing ◽  
Temporal Dimension ◽  
Analysis Measurement ◽  
Materials Research

ABSTRACTHigh resolution (< 1 µm) computed tomography is an attractive tool in materials research due to its ability to non-destructively visualize the three-dimensional internal microstructures of the material. Recently, this technique has been further empowered by adding a fourth (temporal) dimension to study the time-lapse material response under load. Such studies are referred to as four-dimensional or in situ testing. In this snapshot review, we highlight three representative examples of in situ testing using synchrotron radiation computed tomography (SRCT) for composites failure analysis, measurement of local corrosion rate in alloys, and visualization and quantification of electrochemical reactions in lithium-ion batteries, as well as forward-looking integration of machine learning with in situ CT. Lastly, the future opportunities and challenges of in situ SRCT testing are discussed.

scholarly journals Antimicrobial efficiency of photodynamic therapy with different irradiation durations

2013 ◽  
Vol 07 (04) ◽  
pp. 469-473 ◽  
Author(s):  
Cihan Yildirim ◽  
Emine Sirin Karaarslan ◽  
Semih Ozsevik ◽  
Yasemin Zer ◽  
Tugrul Sari ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Brain Heart Infusion ◽  
Control Group ◽  
Test Results ◽  
Human Teeth ◽  
Root Canals ◽  
Single Root ◽  
Antimicrobial Efficiency ◽  
Before And After ◽  
Group 2

ABSTRACT Objective: This study aimed to evaluate the antimicrobial efficiency of PDT and the effect of different irradiation durations on the antimicrobial efficiency of PDT. Materials and Methods: Sixty freshly extracted human teeth with a single root were decoronated and distributed into five groups. The control group received no treatment. Group 1 was treated with a 5% sodium hypochlorite (NaOCl) solution. Groups 2, 3, and 4 were treated with methylene-blue photosensitizer and 660-nm diode laser irradiation for 1, 2, and 4 min, respectively. The root canals were instrumented and irrigated with NaOCl, ethylenediamine-tetraacetic acid, and a saline solution, followed by autoclaving. All the roots were inoculated with an Enterococcus faecalis suspension and brain heart infusion broth and stored for 21 days to allow biofilm formation. Microbiological data on microorganism load were collected before and after the disinfection procedures and analyzed with the Wilcoxon ranged test, the Kruskal-Wallis test, and the Dunn′s test. Results: The microorganism load in the control group increased. The lowest reduction in the microorganism load was observed in the 1-min irradiation group (Group 2 = 99.8%), which was very close to the results of the other experimental groups (99.9%). There were no significant differences among the groups. Conclusions: PDT is as effective as conventional 5% NaOCl irrigation with regard to antimicrobial efficiency against Enterococcus faecalis.

scholarly journals The High Energy Materials Science Beamline (HEMS) at PETRA III

2013 ◽  
Vol 772 ◽  
pp. 57-61 ◽  
Author(s):  
Norbert Schell ◽  
Andrew King ◽  
Felix Beckmann ◽  
Torben Fischer ◽  
Martin Müller ◽  
...  
Keyword(s):  
Smart Materials ◽  
Materials Science ◽  
High Energy ◽  
Test Facility ◽  
Polycrystalline Materials ◽  
Energy Materials ◽  
Friction Stir ◽  
Materials Research ◽  
Set Up

The HEMS beamline at PETRA III has a main energy of 120 keV, is tunable in the range 30-200 keV, and optimized for sub-micrometer focusing with Compound Refractive Lenses. Design, construction, and main funding was the responsibility of the Helmholtz-Zentrum Geesthacht, HZG. Approximately 70 % of the beamtime is dedicated to Materials Research, the rest reserved for “general physics” experiments covered by DESY, Hamburg. The beamline P07 in sector 5 consists of an undulator source optimized for high energies, a white beam optics hutch, an in-house test facility and three independent experimental hutches, plus additional set-up and storage space for long-term experiments. HEMS has partly been operational since summer 2010. First experiments are introduced coming from (a) fundamental research for the investigation of the relation between macroscopic and micro-structural properties of polycrystalline materials, grain-grain-interactions, recrystallisation processes, and the development of new & smart materials or processes; (b) applied research for manufacturing process optimization benefitting from the high flux in combination with ultra-fast detector systems allowing complex and highly dynamic in-situ studies of microstructural transformations, e.g. in-situ friction stir welding; (c) experiments targeting the industrial user community.

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