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Storage Medium (storage + medium)
Selected AbstractsEvaluation of tooth-fragment reattachment: a clinical and laboratory studyDENTAL TRAUMATOLOGY, Issue 4 2010Yucel Yilmaz Materials and Methods:, The clinical study was conducted on 43 fractured incisors: 22 uncomplicated crown fractures (Group A) and 21 complicated crown fractures (Group B). The 43 incisal fragments: 23 were kept dry for 47 h and 20 were kept wet for 24 h by the patients before they were reattached. The fragments were kept in 0.9% saline solution for 30 min before reattachment. The fragments in Group A were reattached using a dentin bonding agent, a flowable and a hybrid resin composite, whereas the fragments in Group B were reattached to the tooth remnant after a pulpotomy was performed. The laboratory study was conducted on 56 extracted incisors. Teeth were divided equally into four groups: Group I , Uncomplicated crown fracture + wet medium; Group II , Uncomplicated crown fracture + dry medium; Group III , Complicated crown fracture + wet medium, and Group IV , Complicated crown fracture + dry medium. The fragments were then reattached in a manner that was similar to that used in the clinical study. The restored teeth were then re-fractured. All data were analyzed statistically. Results: In the clinical study, the restored teeth were followed up for 2 years. Neither the type of trauma nor the storage medium had any significant effect on the survival, color, and bond strength of the restored teeth when assessed in the clinical and laboratory study. The color disharmony that was encountered initially in restored teeth resolved significantly on its own accord within 12 months after reattachment of the fragment. Conclusion: Fragment reattachment can be used to treat fractured teeth successfully in children and adolescents. [source] Effect of temperature and storage media on human periodontal ligament fibroblast viabilityDENTAL TRAUMATOLOGY, Issue 3 2010Beatriz Dulcineia Mendes Souza The purpose of this study was to compare the effectiveness of several storage media to preserve cultured periodontal ligament fibroblasts (PDLF) under different temperatures. The media tested were: sterile Hank's balanced salt solution (sHBSS), non-sterile HBSS (nHBSS), skimmed milk, Save-A-Tooth®, Minimum Essential Medium (MEM) and water (negative control). MEM at 37°C was used as positive control. PDLF were obtained from explants of extracted healthy human teeth. Plates containing confluent PDLF were soaked in the various media for 3, 6, 24, 48 and 72 h at 37°C and 20°C. After incubation, viability of the cells was determined using the tetrazolium salt-based colorimetric (MTT) assay and the Trypan Blue exclusion test after 6, 24, 48 and 72 h of incubation at 20°C. The results were analyzed statistically using Kruskal,Wallis, Scheffé and Mann,Whitney (, = 5%) tests. Results from the MTT assay at 37°C and 20°C showed that skimmed milk was the best storage medium for up to 24 and 48 h, respectively, followed by nHBSS and sHBSS. Results from the Trypan Blue exclusion test showed that the best storage media were milk, sHBSS and nHBSS, with no statistical differences, for any time period. The Save-A-Tooth® had a detrimental effect on cells after 24 h. The influence of temperature on the effectiveness of the storage media tested showed at 20°C a decreasing order of efficacy as follows: milk > sHBSS and nHBSS > MEM > Save-A-Tooth® > water while at 37°C it was: MEM > nHBSS > milk > sHBSS > Save-A-Tooth® > water. In conclusion, incubation temperature altered the effectiveness of the storage media and skimmed milk at 20°C was better than HBSS in maintaining PDLF viability. [source] Parent and caretaker knowledge about avulsion of permanent teethDENTAL TRAUMATOLOGY, Issue 2 2009Marconi Eduardo Sousa Maciel Santos Tooth avulsion, the most severe dentoalveolar lesion, is a dental emergency. The prognosis of avulsed teeth significantly depends on prompt and efficient action at the site of the accident, thus requiring that parents or caretakers be knowledgeable about the correct management of this situation. The objective of the present study was to assess the level of knowledge of parents or caretakers concerning the management of tooth avulsion and to investigate the association between level of knowledge and schooling, monthly family income and age. We interviewed 107 parents or caretakers using a 12-item questionnaire comprising objective questions whose answers received a score from 0 to 3. The results show that 99% of those interviewed would immediately seek professional help; however, 71% did not know what avulsion was. Only 3% would use milk as storage medium and 16% would attempt replantation of the avulsed tooth. The distribution of final means for the overall level of parent or caretaker knowledge was 44.63% for score 3, 15.88% for score 2, 17.99% for score 1 and 21.47% for score 0, showing a low level of knowledge concerning tooth avulsion. Schooling, monthly family income and age were not associated with the knowledge scores for any of the 12 questions. The level of parent and caretaker knowledge concerning the management of tooth avulsion is low, without association with age, schooling and monthly family income. [source] An audit of the time to initial treatment in avulsion injuriesDENTAL TRAUMATOLOGY, Issue 1 2009Betul Kargul Good outcome requires education of the general public and non-dental professionals. Aim:, Retrospective observational survey of case records of avulsion injuries attending a dental hospital trauma clinic. Method:, Data collected included: hospital number, date of birth, gender, source of patient's referral, date of trauma, number of avulsed teeth, place of initial presentation, storage, hours till initial presentation, and initial treatment. Results:, One hundred and twenty teeth with avulsion were identified in 75 children. The mean age of the patients was 9.8 years (SD = 2.3 years) at the time of trauma with avulsions recorded in 44 (58.7%) boys and in 31 (41.3%) girls. Only 51 (42.5%) teeth were stored in an appropriate medium before attendance at any site and only 48 (40%) of the teeth were seen within 1 h. 83.3% received emergency treatment at general hospital, 89.7% in dental practice and 92.9% at dental hospital. Conclusions:, A minority of avulsion injuries were seen within the first hour and a minority were in appropriate storage medium at presentation. Geographical location plays a huge role in the time taken to reach secondary care. However, improving public and non-dental professional knowledge about tooth storage in avulsion injuries is critical to long-term prognosis of the teeth. [source] An investigation into dentists' management methods of dental trauma to maxillary permanent incisors in Victoria, AustraliaDENTAL TRAUMATOLOGY, Issue 4 2008Thai Yeng To a large extent, the management actions of the dentists involved will determine the clinical outcome and, in turn, these actions will be related to their levels of knowledge. The aim of this study was to investigate dentists' knowledge of managing traumatic injuries to maxillary permanent incisors in children. A self-completion questionnaire containing 19 questions on management methods of treating dental trauma was mailed to 693 dentists in Victoria, Australia. The response rate achieved was 61%. This survey found that some of the respondents had adequate management knowledge for the different types of traumatic injuries, while others did not have the correct information. Approximately half the dentists considered milk as the preferred extraoral storage medium of choice for avulsed teeth and a period of 7,10 days splinting after replantation. A large proportion of dentists showed inadequate knowledge with regard to understanding the biological mechanisms causing replacement root resorption (61%) and external inflammatory root resorption (74%). Overall, the respondents to this survey demonstrated only a moderate level of knowledge in management of traumatic injuries to maxillary permanent incisors in children. Continuing professional development programmes may be a means of improving this deficient knowledge base. [source] Dental therapists' experience in the immediate management of traumatized teethDENTAL TRAUMATOLOGY, Issue 2 2006Teresa Loh Abstract,,, The optimal immediate management of traumatized teeth is known to be important for long-term success. One hundred and sixty-seven school dental therapists with General Certificate of Education ,Ordinary' (GCE ,O') level qualification were surveyed on their knowledge and experience on immediate management of dental trauma. The results showed only 41.2% felt comfortable with their present knowledge on the subject. A high proportion of the respondents (94.6%) indicated a need for more knowledge. All therapists concurred on the need to replant a permanent tooth and most (85.1%) agreed that this should be done within 30 min. More than half (54.8%) were not sure of the optimal storage medium for avulsed teeth. Their attitude towards acquiring knowledge in this aspect was good (80.5%) and all would take immediate action to settle appointments for trauma cases. [source] In vitro viability, mitogenicity and clonogenic capacity of periodontal ligament cells after storage in four media at room temperatureDENTAL TRAUMATOLOGY, Issue 2 2000M. Ashkenazi Abstract , The choice of storage medium for preserving traumatically avulsed teeth is important for the success of future replantation. The objective of this study was to compare the effectiveness of four recommended storage media (Hank's balanced salt solution [HBSS], culture medium, , minimal essential medium [,-MEM], and ViaSpan) to preserve cultured periodontal ligament fibroblasts (PDLF) at room temperature (22°C). PDLF were obtained from explants of extracted healthy human teeth. Plates with confluent PDLF were soaked in the various media for 2, 8 and 24 h at room temperature. A control group was incubated with culture medium at 37°C. After incubation, viability of the cells was determined by trypan blue exclusion test. Viable cells were then analyzed for mitogenic (with thymidine) and clonogenic capacity (by culturing one cell/well). Viability of PDLF stored up to 24 h was comparable in all tested media, and the differences were limited to 1%,3%. PDLF stored for up to 24 h in various media had statistically comparable mitogenicity to the control group. After 8 h of storage, the differences were limited to 2%,9%, except for the ,-MEM group which had 23%,29% lower mitogenic capacity compared to the control group. Increasing the storage time up to 24 h further decreased the mitogenicity of the cells by 22%,47%. The highest mitogenicity after 24 h of storage was found in PDLF stored in culture medium or HBSS, and the lowest in ,-MEM. PDLF stored for 2,8 h in various media had a comparable clonogenic capacity to the control group. However, after 24 h, the cells' clonogenic ability dropped by 14%,66%. A similar trend of reduction was noted in the mitogenic and clonogenic capacity, although it was statistically significant only in the clonogenic capacity. Culture medium and ViaSpan, followed by HBSS, were the most effective in preserving the clonogenic capacity of PDLF after 24 h of storage. The lowest clonogenic capacity after 24 h of storage was in the ,-MEM group (66%, P<0.0025). In conclusion, culture medium, followed by HBSS and ViaSpan, was the most effective media for preserving the viability, mitogenicity and clonogenic capacity of PDLF stored for up to 24 h at room temperature. The lowest functional abilities were found in PDLF stored in ,-MEM. [source] Short-term scheduling of a wind generation and hydrogen storage in the electricity marketEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 5 2010G. Tina Abstract Intermittent renewable energy sources (RES) are promising to be the future of electricity generation. In particular wind generation, owing to its stochastic behaviour, has to be carefully managed. Its lack of sufficient predictability decreases the energy value in the current framework of electrical markets, therefore, beyond a certain threshold; this kind of generation into the electrical system represents a problem for the transmission system operator (TSO) during its despatching service. The coupling of wind energy conversion system (WECS) with a storage medium (i.e. hydrogen) could improve the programmability of such generation plants in electrical markets. In this paper, an economical optimization tool has been developed in order to find the short-term scheduling so as to maximize the economic revenues in the day-ahead electricity market of a storage plant coupled with a wind farm. This tool needs as input the forecasts of both wind generation power and market prices, obtained with the adoption of pre-processing input data algorithm based on different methods that involve both statistical and probabilistic approaches. Copyright © 2009 John Wiley & Sons, Ltd. [source] Simulation of heat transfer in the cool storage unit of a liquid,air energy storage systemHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 4 2002Hidefumi Araki Abstract An energy storage system that stores energy in the form of liquid air was studied. In this system, the cool storage unit was the most important unit. From the viewpoint of safety and economy, it was most promising to store the cold energy as the sensitive heat of a solid such as pebbles or concrete. A simulator was developed to predict temperature variations of the solid cool storage unit. The simulator calculated unsteady heat transfer between a supercritical gas flow and the solid material. Comparison of calculated and experimental results showed that the temperature variation of the metal cool storage medium was accurate within 11%. The calculated results showed for the concrete cool storage unit that a smaller quantity of medium was required with a smaller pitch of the tube. The minimum quantity of concrete calculated at the smallest pitch was three times that of concrete, which was simply estimated from the heat capacity of concrete and air. The volume required for concrete cool storage was less than 1/100 that of reservoirs for a pumped-hydro power station having a vertical drop of 500 m. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(4): 284,296, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10035 [source] A feasibility study of using thermal energy storage in a conventional air-conditioning systemINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 11 2004M. M. Hussain Abstract An Erratum has been published for this article in International Journal of Energy Research 2004; 28 (13): 1213. This paper deals with the simulation of thermal energy storage (TES) system for HVAC applications. TES is considered to be one of the most preferred demand side management technologies for shifting cooling electrical demand from peak daytime hours to off peak night hours. TES is incorporated into the conventional HVAC system to store cooling capacity by chilling ethylene glycol, which is used as a storage medium. The thermodynamic performance is assessed using exergy and energy analyses. The effects of various parameters such as ambient temperature, cooling load, and mass of storage are studied on the performance of the TES. A full storage cycle, with charging, storing and discharging stages, is considered. In addition, energy and exergy analysis of the TES is carried out for system design and optimization. The temperature in the storage is found to be as low as 6.4°C after 1 day of charging without load for a mass of 250 000 kg. It is found that COP of the HVAC system increases with the decrease of storage temperature. Energy efficiency of the TES is found to be 80% for all the mass flow rate of the discharging fluid, whereas exergy efficiency varies from 14 to 0.5%. This is in fact due to the irreversibilities in a TES process destroy a significant amount of the input exergy, and the TES exergy efficiencies therefore become always lower than the corresponding energy efficiencies. Copyright © 2004 John Wiley & Sons, Ltd. [source] Hydrogen Storage Mediated by Pd and Pt NanoparticlesCHEMPHYSCHEM, Issue 15 2009Miho Yamauchi Dr. Abstract The hydrogen storage properties of metal nanoparticles change with particle size. For example, in a palladium,hydrogen system, the hydrogen solubility and equilibrium pressure for the formation of palladium hydride decrease with a decrease in the particle size, whereas hydrogen solubility in nanoparticles of platinum, in which hydrogen cannot be stored in the bulk state, increases. Systematic studies of hydrogen storage in Pd and Pt nanoparticles have clarified the origins of these nanosize effects. We found a novel hydrogen absorption site in the hetero-interface that forms between the Pd core and Pt shell of the Pd/Pt core/shell-type bimetallic nanoparticles. It is proposed that the potential formed in the hetero-interface stabilizes hydrogen atoms rather than interstitials in the Pd core and Pt shells. These results suggest that metal nanoparticles a few nanometers in size can act as a new type of hydrogen storage medium. Based on knowledge of the nanosize effects, we discuss how hydrogen storage media can be designed for improvement of the conditions of hydrogen storage. [source] | ||||||||||