Written by Effat Khodadadi, Soraya Khafri, Mahdiyeh Aziznezhad
Parent Category: Year 2016, Volume 8
Category: Volume 8, Issue 5, May 2016
Introduction: Colored compomers are a group of restorative materials that were introduced in 2002 to repair primary teeth, and they provide attractive color and ease of use in pediatric dentistry. The aim of this study was to evaluate the effect of QTH and LED light-curing units on the surface hardness of different colors of Twinky Star compomers.
Methods: In this experimental study, a composite resin (Z250, 3M, and USA), an ionosit compomer (DMG, Germany) with A3 shade and 8 different Twinky Star colored compomer (Voco, Germany) samples were used. In all, 100 samples were prepared with 10 samples in each group, i.e., 10 Z250 composite resin, 10 ionosit compomers, and 10 Twinky Star compomer samples of each color. The samples were prepared in a 4×4-mm Teflon mold. Half of the samples were light-cured with QTH and the other half with LED units. Then, the surface microhardness was measured by Vickers hardness test. The data were analyzed with IBM-SPSS version 22, using the t-test and ANOVA.
Results: Two-way ANOVA showed that the mean surface hardness of the compomer samples cured with the QTH unit was significantly higher than that cured with the LED unit (p < 0.001). In each curing unit, surface hardness of some materials exhibited significant differences with the highest hardness being observed in the Z250 composite resin (650.35 ± 56.320) and the lowest hardness being detected in the ionosit compomers (461.10 ± 96.170). One-way ANOVA also showed that, among the different colors of the Twinky Star compomer, the lowest hardness with both units (QTH and LED) was observed in the gold color (214.32 ± 22.026 and 175.116 ± 15.918, respectively).
Conclusion: The colored compomer and the type of light-curing unit affected the microhardnesses of the surfaces. Different colors of Twinky Star compomers exhibited different surface microhardnesses.
Спортивные костюмыNike WMNS Air Force 1 Shadow White/Hydrogen Blue-Purple
Keywords: Colored compomer, Surface hardness, QTH, LED
Volume 12, Issue 4, October-December 2020
The worldwide spread of COVID-19 as an emerging, rapidly evolving situation, and the dramatic need of urgent medicine or vaccine, has rapidly brought new hypotheses for pathophysiology and potential medicinal agents to the fore. It is crucial that the research community provide a way to publish this research in a timely manner.
To contribute to this important public health discussion, the Electronic Physician Journal is excited to announce a fast-track procedure to help researchers publish their articles on COVID-19 related subjects that fall under the broad definition of public health, internal medicine, and pharmacology. We are especially welcome to all hypotheses about the pathological basis of the COVID-19 infection and the possible characteristics of potential medicine and vaccine. Submit your manuscript here
The 6th World Conference on Research Integrity (WCRI) is to be held on June 2-5, 2019 in Hong Kong.
The WCRI is the largest and most significant international conference on research integrity. Since the first conference in Lisbon in 2007, it has given researchers, teachers, funding agencies, government officials, journal editors, senior administrators, and research students opportunities to share experiences and to discuss and promote integrity in research. Read more:
TDR Clinical Research and Development Fellowships
Call for applications
Deadline for submission: 7 March 2019, 16:00 (GMT)
TDR provides fellowships for early- to mid-career researchers and clinical trial staff (e.g. clinicians, pharmacists, medical statisticians, data managers, other health researchers) in low- and middle-income countries (LMICs) to learn how to conduct clinical trials. Read more:
Meta-Analysis Workshops in New York, USA, and London, UK, in April and May 2019
Don't miss this exceptional opportunity to learn how to perform and report a Meta-analysis correctly. Two Meta-analysis workshops are organized in April and May 2019 by Dr. Michael Borenstein in New York, USA (April 08-10, 2019) and London, UK (May 27-29).
About the Instructor
Dr. Michael Borenstein, one of the authors of Introduction to Meta-Analysis, is widely recognized for his ability to make statistical concepts accessible to researchers as well as to statisticians. He has lectured widely on meta-analysis, including at the NIH, CDC, and FDA. Read more: