scholarly journals A Comparative Evaluation of the Marginal and Internal Fit of Laboratory-fabricated Monolithic Zirconia Crowns using Direct and Indirect Methods of Scanning: An in vitro Study

2017 ◽  
Vol 7 (1) ◽  
pp. 22-27
Author(s):  
Kushal N Gandhi
Keyword(s):  
Stainless Steel ◽  
Indirect Method ◽  
Direct Method ◽  
Indirect Methods ◽  
Zirconia Crowns ◽  
Monolithic Zirconia ◽  
The Mean ◽  
Internal Fit ◽  
Direct And Indirect Methods

ABSTRACT Aim To evaluate the marginal and internal fit of laboratoryfabricated monolithic zirconia crowns using direct and indirect methods of scanning. Materials and methods A stainless steel master model was selected, which included stainless steel die, outer cap, and inner cap. The study was divided into two groups. In group I, direct method of scanning was carried out in which the stainless steel die was scanned directly with chairside scanner, and in group II, impression of the stainless steel die was made and gypsum die was fabricated, which was then subjected to scanning. Zirconia blanks or blocks were milled, sintered, and polished to obtain 10 zirconia crowns of each group. Replica technique was used to evaluate fit of crowns by using light body as cement analog. The crowns were then sectioned, viewed under a stereomicroscope, and each predetermined region was measured and evaluated for marginal and internal fit. Results The descriptive statistics showed that the mean marginal fit for indirect method was higher compared with that for direct method. The results of paired-sample t-test revealed that mean marginal and internal fit for indirect method was on the upper side of the scale, whereas the mean for the direct method is on the lower side of the scale. Thus, the difference in the means of two methods was quite large and likely to be significant. Conclusion The results did show better marginal and internal fit in crowns fabricated by the direct method; however, the crowns fabricated by the indirect method had more discrepancy, but were in the clinically acceptable limit. Clinical significance The present study would serve as a useful guide in deciding which method of scanning would give a better marginal and internal fit of monolithic zirconia crowns for longevity of restorations. How to cite this article Gandhi KN, Ram SM. A Comparative Evaluation of the Marginal and Internal Fit of Laboratory-fabricated Monolithic Zirconia Crowns using Direct and Indirect Methods of Scanning: An in vitro Study. J Contemp Dent 2017;7(1):22-27.

scholarly journals Estimating emission from gas power plant in palembang, indonesia using direct and indirect methods

2018 ◽  
Vol 67 ◽  
pp. 02037
Author(s):  
Gabriel Andari Kristanto ◽  
Alditho Farrasi Anantoputra
Keyword(s):  
Power Plant ◽  
Emission Factor ◽  
Indirect Method ◽  
Emission Inventory ◽  
Direct Method ◽  
Total Particulate Matter ◽  
Indirect Methods ◽  
Gas Power Plant ◽  
A Direct Method ◽  
Direct And Indirect Methods

Nowadays, almost every daily activity is supported by the availability of energy, especially electricity. As the Borang 60 MW Gas Power Plant in Palembang, Indonesia emits air pollutants such as SO2, NOx, CO, and total particulate matter (total PM), an emission inventory needs to be developed. Various methods can be used in the inventory of emissions; among others are a direct method based on direct measurement and an indirect method which involves the calculation of total emissions by emission factor. This study aims to estimate the emissions from the gas power plant in Palembang using direct and indirect methods and analyze the most suitable emission factor for Indonesian conditions. The comparison between emissions measured by direct and indirect methods found that the indirect method using the emission factor of AP-42 gives more accurate results for SO2 and NOx, whereas the total emission of CO is more accurately calculated based on the indirect method using the emission factor developed by Kurokawa et al. (2013); the median value of total PM is more accurately calculated based on the indirect method using the emission factor developed by the IPCC.

scholarly journals The usefulness of operating cash flow information: Does format matter?

2012 ◽  
Vol 10 (1) ◽  
pp. 44-52 ◽  
Author(s):  
Shadi Farshadfar
Keyword(s):  
Cash Flow ◽  
Indirect Method ◽  
Direct Method ◽  
Cash Flows ◽  
Indirect Methods ◽  
Flow Information ◽  
Operating Cash Flow ◽  
Future Cash Flows ◽  
Direct And Indirect Methods ◽  
Level Analysis

This study investigates whether the direct method of presenting cash flows from operations is superior to the indirect method in its ability to forecast future cash flows. It also considers the effect of industry characteristics on the relative usefulness of direct and indirect methods of cash flow presentation. The study, which uses a sample of Australian firms, finds that both the direct and indirect methods improve the forecast of future cash flows. However, the indirect method of reporting cash flows from operations is more relevant than the direct method in predicting future cash flows. Evidence from the industry-level analysis overall reinforces the main results.

scholarly journals In Vitro Comparison of Marginal and Internal Fit of Zirconia Copings Fabricated by One CAD/CAM System with Two Different Scanners

2021 ◽  
Author(s):  
Zahra Khamverdi1 ◽  
Elmira Najafrad ◽  
Maryam Farhadian
Keyword(s):  
T Test ◽  
Marginal Fit ◽  
Significant Difference ◽  
Computer Aided ◽  
Cad Cam ◽  
Zirconia Crowns ◽  
Monolithic Zirconia ◽  
The Mean ◽  
Internal Fit ◽  
Paired T Test

Objectives: Marginal and internal fit of restorations are two important clinical factors for assessing the quality and durability of computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated monolithic zirconia restorations. The purpose of this study was to evaluate the marginal and internal fit of CAD/CAM zirconia crowns with two different scanners (i3D scanner and 3Shape D700). Materials and Methods: Twelve extracted sound human posterior teeth were prepared for full zirconia crowns. Two different extraoral scanners namely i3D scanner and 3Shape D700 were used to digitize type IV gypsum casts poured from impressions. The crowns were milled from presintered monolithic zirconia blocks by a 5-axis milling machine. The replica technique and MIP4 microscopic image analysis software were utilized to measure the marginal and internal fit by a stereomicroscope at ×40 magnification. The collected data were analyzed by paired t-test. Results: The mean marginal gap was 203.62 μm with 3Shape D700 scanner and 241.07 μm with i3D scanner. The mean internal gap was 192.30 μm with 3Shape D700 scanner and 196.06 μm with i3D scanner. The results of paired t-test indicated that there was a statistically significant difference between the two scanners in marginal fit (P=0.04); while, there was no statistically significant difference in internal fit (P=0.761). Conclusion: Within the limitations of this study, the results showed that type of extraoral scanner affected the marginal fit of CAD/CAM fabricated crowns; however, it did not have a significant effect on their internal fit.

scholarly journals Effect of Sintering Time on The Marginal and Internal Fit of Monolithic Zirconia Crowns Containing 3-4 Mol% Y2O3

2021 ◽  
Author(s):  
Yunus Emre Ozden ◽  
M.Baris Guncu ◽  
Guliz Aktas ◽  
Senay Canay
Keyword(s):  
Tetragonal Zirconia ◽  
Cubic Phase ◽  
Marginal Gap ◽  
Sintering Time ◽  
Zirconia Crowns ◽  
Monolithic Zirconia ◽  
The Mean ◽  
Internal Fit ◽  
Tetragonal Zirconia Polycrystal ◽  
Gap Values

Abstract Background Short-time sintering may offer advantages including saving time and energy but there is limited evidence on the effect that altering sintering time has on the accuracy of monolithic zirconia crowns. The purpose of this in vitro study was to investigate the effect of shortened sintering time on the marginal and internal fit of 3Y-TZP (three mol% yttria-stabilized tetragonal zirconia polycrystal) and 4Y-TZP (four mol% yttria-stabilized tetragonal zirconia polycrystal) monolithic crowns. Methods Sixty monolithic zirconia crowns were fabricated for the maxillary first molar tooth on the prefabricated implant abutment. Groups were created according to the material composition: 3Y-TZP Generation 1 (alumina wt; ≤0.5%, < 15% cubic phase), 3Y-TZP Generation 2 (alumina wt; ≤0.05%, < 15% cubic phase) and 4Y-TZP (alumina wt; ≤0.05%, > 25% cubic phase). Two different sintering protocols were performed: same final sintering temperature (1500°C) and various rates of heating (10°C/min and 40°C/min), cooling down speed (-10°C/min and − 40°C/min), holding time (45 and 120 minutes), and total sintering time (approximately 2 and 7 hours, respectively). The marginal and internal fit of the crowns were determined using the silicone replica technique. Comparisons between groups and sintering times were analyzed using two-way ANOVA. Pairwise multiple comparisons were performed using the t-test (p < 0.05). Results The mean marginal gap values of 4Y-TZP zirconia revealed statistically significant increase for the speed sintering protocol (p < 0.0001), while no difference was observed between the sintering protocols for the mean marginal gap values of 3Y-TZP groups. Conclusions Although all groups showed clinically acceptable gap values (<120 µm), altering the sintering time had an effect on the marginal fit of the crowns manufactured from 4Y-TZP zirconia. Shortening the sintering time may lead to differences within clinically acceptable limits. The manufacturer's recommendations according to material composition should be implemented with care.

scholarly journals The Preference of Direct or Indirect Methods in Preparing the Statement of Cash Flows in Decision Making: An Academic Perspective

2016 ◽  
Vol 8 (2) ◽  
pp. 206
Author(s):  
Abdullah, S. Hardan ◽  
Majed, A. Qabajeh ◽  
Aymen, M. Alshanti
Keyword(s):  
Decision Making ◽  
Indirect Method ◽  
Direct Method ◽  
Cash Flows ◽  
Decision Makers ◽  
Academic Rank ◽  
Indirect Methods ◽  
Statement Of Cash Flows ◽  
Qualitative Characteristics ◽  
Academic Sector

Two methods are used when reporting cash flows from operating activities: the direct method or the indirect method, both are acceptable from IAS with a preference of direct method. Thus, this paper examines which method of reporting the statement of cash flows provides useful information the decision makers rely on for decision making purposes. To achieve this aim, participants were selected from academic sector represented by universities professors. The study is based on the conceptual framework: qualitative characteristics of accounting information. To be useful, information must be relevant and represents faithfully what it claims to represent. In order to distinguish more useful financial information from those less useful, enhancing qualitative characteristics were examined. Results show that academic professors provide support for direct method of reporting cash flows over indirect method. The study sought to determine the effect of academic rank on these results. Evidence reveals that full and associate professors endorsed the preference of direct method more than assistant professors and lecturers. These results recommend the legislative bodies and entities to adopt the direct method in preparation the statement of cash flows.

scholarly journals Load-Bearing Capacity of Zirconia Crowns Screwed to Multi-Unit Abutments with and without a Titanium Base: An In Vitro Pilot Study

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3056
Author(s):  
Hadas Heller ◽  
Adi Arieli ◽  
Ilan Beitlitum ◽  
Raphael Pilo ◽  
Shifra Levartovsky
Keyword(s):  
Failure Modes ◽  
Load Bearing ◽  
Zirconia Crowns ◽  
Group A ◽  
Monolithic Zirconia ◽  
Loading Tests ◽  
Group B ◽  
Iso 14801 ◽  
Static And Dynamic Loading

The static and dynamic load-bearing capacities and failure modes of zirconia crowns screwed to multi-unit abutments (MUAs) with and without a titanium base (T-base) were determined. Thirty-six monolithic zirconia crowns screwed to straight MUAs torqued to laboratory analogs (30 Ncm) were assigned to two groups (n = 18). In group A, the zirconia crowns were screwed directly to the MUAs; in group B, the zirconia crowns were cemented to the T-base and screwed to the MUAs. All specimens were aged in 100% humidity (37 °C) for one month and subjected to thermocycling (20,000 cycles). Afterwards, the specimens underwent static and dynamic loading tests following ISO 14801. The failure modes were evaluated by stereomicroscopy (20×). There was an unequivocally similar trend in the S-N plots of both specimen groups. The load at which the specimens survived 5,000,000 cycles was 250 N for both groups. Group A failed mainly within the metal, and zirconia failure occurred only at a high loading force. Group B exhibited failure within the metal mostly in conjunction with adhesive failure between the zirconia and T-base. Zirconia restoration screwed directly to an MUA is a viable option, but further studies with larger sample sizes are warranted.

scholarly journals Evaluation of marginal fit of two allceramic copings with two finish lines

2012 ◽  
Vol 06 (02) ◽  
pp. 163-168 ◽  
Author(s):  
Gulce Subasi ◽  
Nilgun Ozturk ◽  
Inan Ozgur ◽  
Nalan Bozogullari
Keyword(s):  
Stainless Steel ◽  
Analysis Of Variance ◽  
In Vitro Study ◽  
Finish Line ◽  
Marginal Fit ◽  
Luting Agent ◽  
All Ceramic ◽  
The Mean ◽  
Line Design

ABSTRACTObjectives: This in-vitro study investigated the marginal fit of two all-ceramic copings with 2 finish line designsMethods: Forty machined stainless steel molar die models with two different margin designs (chamfer and rounded shoulder) were prepared. A total of 40 standardized copings were fabricated and divided into 4 groups (n=10 for each finish line-coping material). Coping materials tested were IPS e.max Press and Zirkonzahn; luting agent was Variolink II. Marginal fit was evaluated after cementation with a stereomicroscope (Leica MZ16). Two-way analysis of variance and Tukey-HSD test were performed to assess the influence of each finish line design and ceramic type on the marginal fit of 2 all-ceramic copings (α =.05) Results: Two-way analysis of variance revealed no statistically significant differences for marginal fit relative to finish lines (P=.362) and ceramic types (P=.065)Conclusion: Within the limitations of this study, both types of all-ceramic copings demonstrated that the mean marginal fit was considered acceptable for clinical application (≤120 μm). (Eur J Dent 2012;6:163-168)

Direct and Indirect Methods for Calculating Thermal Emission From Layered Structures With Nonuniform Temperatures

2011 ◽  
Vol 133 (7) ◽  
Author(s):  
L. P. Wang ◽  
S. Basu ◽  
Z. M. Zhang
Keyword(s):  
Temperature Distribution ◽  
Thermal Emission ◽  
Local Density ◽  
Direct Method ◽  
Direct Methods ◽  
Layered Structures ◽  
Nonuniform Temperature ◽  
Indirect Methods ◽  
Nonuniform Temperature Distribution ◽  
Direct And Indirect Methods

The determination of emissivity of layered structures is critical in many applications, such as radiation thermometry, microelectronics, radiative cooling, and energy harvesting. Two different approaches, i.e., the “indirect” and “direct” methods, are commonly used for computing the emissivity of an object. For an opaque surface at a uniform temperature, the indirect method involves calculating the spectral directional-hemispherical reflectance to deduce the spectral directional emissivity based on Kirchhoff’s law. On the other hand, a few studies have used a combination of Maxwell’s equations with the fluctuation-dissipation theorem to directly calculate the emissivity. The present study aims at unifying the direct and indirect methods for calculating the far-field thermal emission from layered structures with a nonuniform temperature distribution. Formulations for both methods are given to illustrate the equivalence between the indirect and the direct methods. Thermal emission from an asymmetric Fabry–Pérot resonance cavity with a nonuniform temperature distribution is taken as an example to show how to predict the intensity, emissivity, and the brightness temperature. The local density of states, however, can only be calculated using the direct method.

scholarly journals Measurement the “Q” angle through the application of direct method and indirect method

2016 ◽  
Vol 33 (03) ◽  
pp. 168-170
Author(s):  
C. Vanzeli ◽  
A. Reis ◽  
A. Pereira ◽  
M. Tavares ◽  
V. Fazan
Keyword(s):  
Direct Method ◽  
Objective Measure ◽  
Angle Measurement ◽  
Global Alignment ◽  
Ordinary People ◽  
Lateral Deviation ◽  
Indirect Methods ◽  
Q Angle ◽  
Direct And Indirect Methods ◽  
Physiotherapy Clinic

Abstract Introduction: The “Q” angle is used to measure global alignment of the kneecap, representing the kneecap normal alignment. The average of 15 degrees in ordinary people is accepted as “Q” angle value, 14 degrees for men and 17 degrees for women. Anatomic changes caused by variants produces converging kneecaps or lateral deviation of the tibial tuberosity, changing the “Q” angle value and causing pathologies. Objective: Measure the “Q” angle of asymptomatic people, comparing obtained results. Materials and Methods: The “Q” angle measurement was taken from 12 subjects (6 males and 6 females), with ages from 18 to 35, at the Physiotherapy Clinic of José do Rosario Vellano College, in Alfenas, MG. Results: After evaluating the 12 subjects following ANOVA test, using p < 0.05, no significant statistic difference could be observed among examiners, gender or right and left limbs, considering both direct and indirect methods. Conclusion: Data obtained in this research allows us suggest that there is no difference between “Q” angle values among genders, direct and indirect methods and lateral symmetry.

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