The influence of storage conditions on the physicochemical properties and dimensional accuracy of the alginate impressions

2018 ◽  
Vol 2 (87) ◽  
pp. 68-76
Author(s):  
K. Żelezińska ◽  
M. Nowak ◽  
J. Żmudzki ◽  
C. Krawczyk ◽  
G. Chladek
Keyword(s):  
Tensile Strength ◽  
Design Methodology ◽  
Dimensional Accuracy ◽  
Storage Conditions ◽  
Materials Properties ◽  
Dimensional Changes ◽  
Impression Materials ◽  
Master Model ◽  
Good Relation ◽  
Practical Implications

Purpose: Alginate impression materials are the most commonly used masses for taking impressions. They are characterized by good relation of properties to the price. However, the main problem associated with use of the impression masses is dimensions stability. Manufacturers of alginate masses recommend storage impression without any source of moisture, but dentists frequently store impressions wrapped in a wet materials. This may be the a reason of changes in dimensions and other properties. Moreover, it is recognized, that casting the model in the soon after making impression guarantee better dimensional accuracy. However, models are made usually after 24h. For some masses producers claim unequivocally, that the impressions can be stored for up to 168 h without changing the dimensions. So in this study was investigates how storage conditions affect chosen properties of alginate mass, including the accuracy of the models. Design/methodology/approach: Samples were prepared according to the manufacturer instruction and divided into 5 groups. Measurements were made 20 min after taking the impression and after 24h/168h of storage with/ without the resource of moisture. The measurements of Shore A hardness, tensile strength, mass changes and dimensional changes were made. Accuracies of the dental stone models were investigated with models manufactured after 20 min and 168 h after impressions, in comparison to the master model. Findings: The study showed that the storage conditions and time of storage had influence on properties of alginate impression mass. The resource of moisture has got an influence on dimensions and mass changes, tensile strength, elongation and shore A hardness. The results show that the use of the resource of moisture may be a cause of unfavourable changes in the gypsum model dimensions. Research limitations/implications: The storing of the alginate impressions with the resource of moisture is commonly practiced by the doctors, but it inconsistent with the manufacturer's recommendation. Practical implications: The method storing of the alginate impressions determined not only the materials properties, but also the clinical properties of final products like dentures. Originality/value: The significant of the method of the storing of alginate impression materials on the chosen properties of the materials and the accuracy of the dental stone models were shown.

scholarly journals Evaluation and Comparison of Dimensional Accuracy of Newly Introduced Elastomeric Impression Material using 3D Laser Scanners: An in vitro Study

2013 ◽  
Vol 14 (2) ◽  
pp. 265-268 ◽  
Author(s):  
Naveen S Yadav ◽  
Teerthesh Jain ◽  
Amrita Pandita ◽  
SMA Feroz ◽  
Pradeep LNU ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Laser Scanner ◽  
In Vitro Study ◽  
Dimensional Accuracy ◽  
Time Intervals ◽  
Impression Material ◽  
Impression Materials ◽  
Laser Scanners ◽  
Master Model

ABSTRACT Aim Aim of the present study was to comparatively evaluate dimensional accuracy of newely introduced elastomeric impression material after repeated pours at different time intervals. Materials and methods In the present study a total of 20 (10 + 10) impressions of master model were made from vinyl polyether silicone and vinyl polysiloxane impression material. Each impression was repeatedly poured at 1, 24 hours and 14 days. Therefore, a total of 60 casts were obtained. Casts obtained were scanned with three-dimensional (3D) laser scanner and measurements were done. Results Vinyl polyether silicone produced overall undersized dies, with greatest change being 0.14% only after 14 days. Vinyl polysiloxane produced smaller dies after 1 and 24 hours and larger dies after 14 days, differing from master model by only 0.07% for the smallest die and to 0.02% for the largest die. Conclusion All the deviations measured from the master model with both the impression materials were within a clinically acceptable range. Clinical significance In a typical fixed prosthodontic treatment accuracy of prosthesis is critical as it determines the success, failure and the prognosis of treatment including abutments. This is mainly dependent upon fit of prosthesis which in turn is dependent on dimensional accuracy of dies, poured from elastomeric impressions. How to cite this article Pandita A, Jain T, Yadav NS, Feroz SMA, Pradeep, Diwedi A. Evaluation and Comparison of Dimensional Accuracy of Newly Introduced Elastomeric Impression Material using 3D Laser Scanners: An in vitro Study. J Contemp Dent Pract 2013;14(2):265-268.

scholarly journals A Comparative Study on Accuracy and Reproducibility of Alginate and Addition Reaction Silicone as an Impression Materials.

2014 ◽  
Vol 3 (2) ◽  
pp. 28-33
Author(s):  
Shakila Fatema ◽  
Sheikh Md Shahriar Quader ◽  
Mohammad Shamsuzzaman ◽  
Mirza Md Arifur Rahman ◽  
Nasima Khan
Keyword(s):  
Addition Reaction ◽  
In Vitro Study ◽  
Dimensional Accuracy ◽  
Horizontal Line ◽  
Impression Material ◽  
Dimensional Changes ◽  
Impression Materials ◽  
Study Results ◽  
Surface Detail

Background: To achieve accuracy and exact reproduction of prosthesis, choosing a perfect impression material is essential. Especially to make the prosthesis as accurately as possible, impression material should possess some essential properties, like; minimum dimensional changes, good flow ability and easy removal. Purpose: The aim of this study was to evaluate the accuracy and surface detail reproduction of Alginate and Addition Reaction Silicone as an impression materials. Method: This is an experimental in vitro study. In this study Impression by Alginate and Addition Reaction Silicone were made using a round stainless steel test block with three horizontal lines and two vertical lines. The horizontal lines were used for evaluating the surface detail reproduction, and vertical lines were provided for the dimensional accuracy. For dimensional accuracy the length of the middle horizontal line in between vertical lines and the distance between the top and bottom horizontal line was measured using travelling microscope. And for surface detail reproduction three horizontal line of one segment were observed under stereomicroscope. Result: According to study results Addition Reaction Silicone is better than Alginate regarding quality of impression. Conclusion: In comparison to Alginate, Addition Reaction Silicone might have better performance about accuracy and surface detail reproduction. DOI: http://dx.doi.org/10.3329/updcj.v3i2.17996 Update Dent. Coll. j: 2013; 3 (2): 28-33

Structure changes and water filtration properties of electrospun polyamide nanofibre membranes

2016 ◽  
Vol 73 (8) ◽  
pp. 1920-1926 ◽  
Author(s):  
N. Daels ◽  
L. Harinck ◽  
A. Goethals ◽  
K. De Clerck ◽  
S. W. H. Van Hulle
Keyword(s):  
Tensile Strength ◽  
Dimensional Change ◽  
Storage Conditions ◽  
Water Filtration ◽  
Dimensional Changes ◽  
Structure Changes ◽  
Bacterial Removal ◽  
Heat Treated ◽  
Filtration Properties

Nanofibre membranes are studied extensively in water treatment. Inappropriate storage, however, could alter their performance, e.g. regarding water filtration. This shows the need for investigating this effect in more detail so as to offer a solution for long-term behaviour and stability. In this study, polyamide nanofibre membranes were treated under different conditions, simulating the diverse storage conditions and to simulate their use in water filtration systems. Under all these different settings, nanofibre properties (scanning electron microscope pictures, dimensional changes, tensile strength) and water filtration performance (clean water permeability (CWP), bacterial removal) were investigated. The results demonstrate that, as soon as the dimensional change of a membrane is >2%, the CWP, tensile strength and bacterial removal significantly decrease. These dimensional changes occurred when the membrane became dry after it had been in contact with water. As such, it is important to keep the membrane either in dry or in wet conditions to store its unique properties. When heat-treated, the membrane had a higher tensile strength and kept its morphology and characteristics better during storage.

scholarly journals Linear Dimensional Change and Ultimate Tensile Strength of Polyamide Materials for Denture Bases

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3446
Author(s):  
Bozhana Chuchulska ◽  
Stefan Zlatev
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
The Netherlands ◽  
Artificial Aging ◽  
Dimensional Change ◽  
Storage Conditions ◽  
Control Group ◽  
P Values ◽  
Dimensional Changes ◽  
And Storage

The aim of the current study was to evaluate the dimensional changes and ultimate tensile strength in three polyamide materials for denture bases fabrication through injection molding, subjected to artificial aging and different storage conditions. A total of 333 test specimens fabricated from Biosens (BS; Perflex, Netanya, Israel), Bre.flex 2nd edition (BF; Bredent, Senden, Germany) and ThermoSens (TS; Vertex Dental B.V., Soesterberg, The Netherlands)—n = 111 per material—were equally divided into three groups (n = 37) based on different treatments and storage conditions. Test samples allocated to the “Control group” were not artificially aged and stored in water for 24 h. Both “Treatment 1 group” and “Treatment 2 group” were subjected to thermocycling, the former dehydrated and the latter stored in water between cycle-sets. Linear changes and ultimate tensile strength were measured and analyzed for storage condition and material influence on the outcome variables. A Welch ANOVA test with Games–Howell post-hoc analysis was used to compare the influence of treatments across different materials. Significant differences were found for all three included materials with p values ranging from <0.05 to <0.001 for linear dimensional changes. The magnitude of alterations varied and was large for BS (Perflex, Israel) (ω2 = 0.62) and BF (Bredent, Germany) (ω2 = 0.47) and small but significant for TS (Vertex Dental B.V., The Netherlands) (ω2 = 0.05). However, results seem to fall into clinically acceptable range. Significant differences were also observed for the ultimate tensile strength test with the same range of p-values. All three materials showed different initial ultimate tensile strengths and varying reaction to artificial aging and storage with the lowest alterations observed for BF (Bredent, Germany) (ω2 = 0.05). Within the limitation of this study, it can be concluded that all three materials show different dimensional and mechanical properties when subjected to artificial aging and different storage. Although linear dimensions show significant changes, they seem to be clinically irrelevant, whereas the change in ultimate tensile strength after only 6-month equivalent clinical use was substantial for BS (Perflex, Israel) and TS (Vertex Dental B.V., The Netherlands).

Consumer value creation through WhatsApp use

2019 ◽  
Vol 32 (4) ◽  
pp. 455-471
Author(s):  
Jorge Cruz-Cárdenas ◽  
Jorge Guadalupe-Lanas ◽  
Ekaterina Zabelina ◽  
Andrés Palacio-Fierro ◽  
Margarita Velín-Fárez ◽  
...  
Keyword(s):  
Latin American ◽  
Value Creation ◽  
Emotional Support ◽  
Design Methodology ◽  
Instant Messaging ◽  
Role Performance ◽  
Content Type ◽  
Consumer Value ◽  
Depth Interviews ◽  
Practical Implications

Purpose The purpose of this paper is to understand in-depth how consumers create value in their lives using WhatsApp, the leading mobile instant messaging (MIM) application. Design/methodology/approach The study adopts the perspective of customer-dominant logic (CDL) and uses a qualitative multimethod design involving 3 focus groups and 25 subsequent in-depth interviews. The research setting was Ecuador, a Latin American country. Findings Analysis and interpretation of the participants’ stories made it possible to identify and understand the creation of four types of value: maintaining and strengthening relationships; improving role performance; emotional support; and entertainment and fun. In addition, the present study proposes a conceptual model of consumer value creation as it applies to MIM. Practical implications Understanding the way consumers create value in their lives using MIM is important not only for organizations that offer MIM applications, but also for those companies that develop other applications for mobile phones or for those who wish to use MIM as an electronic word-of-mouth vehicle. Originality/value The current study is one of the first to address the topic of consumer behavior in the use of technologies from the perspective of CDL; this perspective enables an integrated qualitative vision of value creation in which the consumer is the protagonist.

scholarly journals Advantages and potential challenges of data management in e-maintenance

2019 ◽  
Vol 25 (3) ◽  
pp. 378-396 ◽  
Author(s):  
Arian Razmi-Farooji ◽  
Hanna Kropsu-Vehkaperä ◽  
Janne Härkönen ◽  
Harri Haapasalo
Keyword(s):  
Data Management ◽  
Design Methodology ◽  
Management Practices ◽  
Future Research ◽  
Conceptual Approach ◽  
Content Type ◽  
Different Types ◽  
Maintenance Systems ◽  
Industry Leader ◽  
Practical Implications

Purpose The purpose of this paper is twofold: first, to understand data management challenges in e-maintenance systems from a holistically viewpoint through summarizing the earlier scattered research in the field, and second, to present a conceptual approach for addressing these challenges in practice. Design/methodology/approach The study is realized as a combination of a literature review and by the means of analyzing the practices on an industry leader in manufacturing and maintenance services. Findings This research provides a general understanding over data management challenges in e-maintenance and summarizes their associated proposed solutions. In addition, this paper lists and exemplifies different types and sources of data which can be collected in e-maintenance, across different organizational levels. Analyzing the data management practices of an e-maintenance industry leader provides a conceptual approach to address identified challenges in practice. Research limitations/implications Since this paper is based on studying the practices of a single company, it might be limited to generalize the results. Future research topics can focus on each of mentioned data management challenges and also validate the applicability of presented model in other companies and industries. Practical implications Understanding the e-maintenance-related challenges helps maintenance managers and other involved stakeholders in e-maintenance systems to better solve the challenges. Originality/value The so-far literature on e-maintenance has been studied with narrow focus to data and data management in e-maintenance appears as one of the less studied topics in the literature. This research paper contributes to e-maintenance by highlighting the deficiencies of the discussion surrounding the perspectives of data management in e-maintenance by studying all common data management challenges and listing different types of data which need to be acquired in e-maintenance systems.

An exploratory empirical study of whistleblowing and whistleblowers

2020 ◽  
Vol 27 (3) ◽  
pp. 755-770
Author(s):  
Maria Krambia-Kapardis
Keyword(s):  
Statistical Analysis ◽  
Design Methodology ◽  
Research Topic ◽  
Due Date ◽  
Content Type ◽  
Unethical Behaviour ◽  
Eu Member States ◽  
European Directive ◽  
Original Survey ◽  
Practical Implications

Purpose The purpose of this study is to develop a profile of whistleblowers and to determine whether whistleblowing legislation would encourage those individuals to bring to light some illegal or unethical behaviour that otherwise would remain in the shadows. Design/methodology/approach Having identified whistleblowing correlation, a survey was carried out in Cyprus of actual whistleblowers and could-have-been whistleblowers. Findings Males between 46 and55 years of age, regardless of whether they have dependents or hold senior positions in organizations are significantly more likely to blow the whistle. However, could-have-been whistleblowers did not go ahead because they felt that the authorities would not act on their information. Research limitations/implications Because of the sensitive nature of the research topic and the fact that only whistleblowers or intended whistleblowers could participate in the study, the sample size is limited as a result. This, in turn, limits both the number of respondents in each category (actual and intended) as well as constrains the statistical analysis that could be carried out on the data. Practical implications It remains to be seen whether EU Member States shall implement the European Directive 2019/1937 on the protection of persons who report breaches of Union Law, in its entirety by the due date, namely December 2021. Originality/value This study provides a literature review of whistleblowing and reports an original survey against the backdrop of the European Directive.

scholarly journals Evaluation of dimensional accuracy of dental bridges manufactured with conventional casting technique and CAD/CAM system with Ceramill Sintron blocks using CMM

2018 ◽  
Vol 12 (4) ◽  
pp. 264-271 ◽  
Author(s):  
Alireza Izadi ◽  
Fariborz Vafaee ◽  
Arash Shishehian ◽  
Ghodratollah Roshanaei ◽  
Behzad Fathi Afkari
Keyword(s):  
Reference Model ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Three Dimensions ◽  
Casting Technique ◽  
Dimensional Changes ◽  
Conventional Casting ◽  
Cad Cam ◽  
Milling Method ◽  
Measuring Machine

Background. Recently, non-presintered chromium-cobalt (Cr-Co) blocks with the commercial name of Ceramill Sintron were introduced to the market. However, comprehensive studies on the dimensional accuracy and fit of multi-unit frameworks made of these blocks using the coordinate measuring machine (CMM) are lacking. This study aimed to assess and compare the dimensional changes and fit of conventional casting and milled frameworks using Ceramill Sintron. Methods. A metal model was designed and scanned and 5-unit frameworks were fabricated using two techniques: (I) the conventional casting method (n=20): the wax model was designed, milled in the CAD/CAM machine, flasked and invested; (II) the milling method using Ceramill Sintron blocks (n=20): the wax patterns of group 1 were used; Ceramill Sintron blocks were milled and sintered. Measurements were made on the original reference model and the fabricated frameworks using the CMM in all the three spatial dimensions, and dimensional changes were recorded in a checklist. Data were analyzed with descriptive statistics, and the two groups were compared using one-way ANOVA and Tukey test (α=0.05). Results. The fabricated frameworks in both groups showed significant dimensional changes in all the three dimensions. Comparison of dimensional changes between the two groups revealed no significant differences (P>0.05) except for transverse changes (arch) that were significantly greater in Ceramill Sintron frameworks (P<0.05). Conclusion. The two manufacturing processes were the same regarding dimensional changes and the magnitude of marginal gaps and both processes resulted in significant dimensional changes in frameworks. Ceramill Sintron frameworks showed significantly greater transverse changes than the conventional frameworks.

How Phillips saw the light

2020 ◽  
Vol 36 (8) ◽  
pp. 29-31
Keyword(s):  
Design Methodology ◽  
Reading Time ◽  
Daily Basis ◽  
Business World ◽  
Content Type ◽  
Freak Show ◽  
The World ◽  
Pertinent Information ◽  
The One ◽  
Practical Implications

Purpose Reviews the latest management developments across the globe and pinpoints practical implications from cutting-edge research and case studies. Design/methodology/approach This briefing is prepared by an independent writer who adds their own impartial comments and places the articles in context. Findings The problem with developing a reputation of being something of an oracle in the business world is that all of a sudden, everyone expects you to pull off the trick of interpreting the future on a daily basis. Like a freak show circus act or one-hit wonder pop singer, people expect you to perform when they see you, and they expect you to perform the thing that made you famous, even if it is the one thing in the world you don’t want to do. And when you fail to deliver on these heightened expectations, you are dismissed as a one trick pony, however good that trick is in the first place. Originality/value The briefing saves busy executives and researchers hours of reading time by selecting only the very best, most pertinent information and presenting it in a condensed and easy-to-digest format.

scholarly journals Examining the accounts of oil spills crises in Nigeria through sensegiving and defensive behaviours

2020 ◽  
Vol 33 (8) ◽  
pp. 2053-2076 ◽  
Author(s):  
Osamuyimen Egbon ◽  
Chijoke Oscar Mgbame
Keyword(s):  
Policy Implication ◽  
Design Methodology ◽  
Oil Spills ◽  
Burden Of Proof ◽  
Multinational Companies ◽  
External Factors ◽  
Content Type ◽  
Political Dynamics ◽  
Defensive Behaviours ◽  
Practical Implications

PurposeThe paper examines how oil multinational companies (MNCs) in Nigeria framed accounts to dissociate themselves from causing oil spills.Design/methodology/approachThe authors utilised data from relevant corporate reports, external accounts and interviews, and used sensegiving with defensive behaviours theoretical framing to explore corporate narratives aimed at altering stakeholders' perceptions.FindingsThe corporations gave sense to their audience by invoking scapegoating blame avoidance narrative in attributing the cause of most oil spills in Nigeria to outsiders (sabotage), despite potentially misclassifying the sabotage-corrosion dichotomy. Corporate stance was reinforced through justifying narrative, which suggested that multi-stakeholders jointly determined the causes of oil spills, thus portraying corporate accounts as transparent, credible and objective.Research limitations/implicationsThe socio-political dynamics in an empirical setting affect corporate accounts and how those accounts appear persuasive, implying that such contextual factors merit consideration when evaluating corporate accounts. For example, despite contradictions in corporate accounts, corporate attribution of oil spills to external factors appeared persuasive due to the inherently complicated socio-political dynamics.Practical implicationsWith compensation to oil spills' victims only legally permitted for non-sabotage-induced spills alongside the burden of proof on the victims, the MNCs are incentivised to attribute most oil spills to sabotage. On policy implication, accountability would be best served when the MNCs are tasked both with the burden of proof and a responsibility to demonstrate their transparency in preventing oil spills, including those caused by sabotage.Originality/valueCrisis situations generate multiple and competing perspectives, but sensegiving and defensive behaviours lenses enrich our understanding of how crisis-ridden companies frame narratives to alter stakeholders' perceptions. Accounts-giving therefore partly satisfies accountability demands, and acts as sensegiving signals aimed at reframing/redefining existing perceptions.

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