Introduction: Preventive resin restorations (PRR) are the conservative choice for the most common carious lesions in children. Thus, new age flowable resin composites with higher filler content are readily used. The aim of this study was to evaluate the microshear bond strength and microleakage of two flowable resin composites containing different percentages of nano zinc oxide (NZnO) particles, which have proven to have antimicrobial properties.

Methods: This experimental in-vitro study was carried out in the Dental Material Research Center of Babol University of Medical Sciences in 2015. One nanohybrid and one nanofill flowable resin composite were chosen and modified with the incorporation of 1% and 3% Wt NZnO particles. Six groups (n=10, 0%, 1%, and 3%) of resin composite sticks on dental enamel (2×2mm) were prepared to be placed in the microtensile tester. The microshear bond strength magnitude (MPa) was recorded at the point of failure. A class I box (3×0.8×1 mm) was prepared on 60 premolars and filled using the resin composites (6 groups, n=10). The specimens were immersed in a 5% basic fuschin solution and sectioned bucco-lingually to view the microleakage using a stereomicroscope. One-way ANOVA and Tukey tests for microshear and Wilcoxon and Kruskal–Wallis tests for microleakage were used to analyze the data in the IBM SPSS Statistics version 22 software.

Results: The bond strength of the 3% clearfill group significantly decreased while no significant change occurred in the bond strength in other groups. The Z-350 group had significantly lower microleakage as nanoparticles increased. No significant difference was observed in the clearfill group. 

Conclusion: Up to 3% Wt incorporation of NZnO particles will not diversely alter the bond strength, but it will be beneficial in providing antimicrobial effects with lower microleakage rates.


Keywords: Dental leakage; Flowable composite; Nanoparticles; Shear strength; Zinc oxide
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July-September 2019 (Volume 11, Issue 3)


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In the second issue of the journal Electronic Physician for 2019, we have several papers including four Randomized Controlled Trials, a model development study, a case report, an editorial, a letter to editor (LTE), and several original research including two studies with qualitative approach. Authors of this issue are from nine countries: Iran, The Netherlands, Sweden, Italy, India, Thailand, Saudi Arabia, United Arab Emirates (UAE), and Jordan. Read more...


The 6th World Conference on Research Integrity (WCRI) is to be held on June 2-5, 2019 in Hong Kong.

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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: