Objective: This study evaluated the effect of ferrule preparation (Fp) on the fracture resistance of endodontically treated teeth, restored with composite resin cores with or without glass fiber posts.
Material And Methods: Forty-four bovine teeth were sectioned 19 or 17 mm (2 mm ferrule) from the apex, endodontically treated and assigned to four groups (n = 11): Group 1: Fp and post; Group 2: Fp and without post; Group 3: without Fp and with post; Group 4: without Fp and without post. All specimens were restored with composite resin core and metal crown. Specimens were subjected to fracture resistance testing in a universal testing machine at a crosshead speed of 0.5 mm/min. The data were analyzed by two-way ANOVA and Tukey's tests (α=0.05).
Results: The mean fracture resistance values were as follows: Group 1: 573.3 N; Group 2: 552.5 N; Group 3: 275.3 N; Group 4: 258.6 N. Significantly higher fracture resistance was found for the groups with Fp (p<0.001).
Conclusion: There was no statistically significant interaction between the "Fp" and "post" factors (p = 0.954). The ferrule preparation increased the fracture resistance of endodontically treated teeth. However, the use of glass fiber post showed no significant influence on the fracture resistance.
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http://dx.doi.org/10.1590/s1678-77572010000400007 | DOI Listing |
Mater Horiz
January 2025
College of Materials Science & Engineering, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
Developing hydrogels with high conductivity and toughness a facile strategy is important yet challenging. Herein, we proposed a new strategy to develop conductive hydrogels by growing metal dendrites. Water-soluble Sn ions were soaked into the gel and then converted to Sn dendrites an electrochemical reaction; the excessive Sn ions were finally removed by water dialysis, accompanied by dramatic shrinkage of the gel.
View Article and Find Full Text PDFACS Macro Lett
January 2025
School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.
Stimuli-responsive polymers have demonstrated significant potential in the development of smart materials due to their capacity to undergo targeted property changes in response to external physical or chemical stimuli. However, the scales of response in most existing stimuli-responsive polymer systems are mainly focused on three levels: functional units, chain conformations, or polymer topologies. Herein, we have developed a covalent polymer network (CPN) capable of converting into a supramolecular polymer network (SPN) within bulk materials directly at the scale of polymer network types.
View Article and Find Full Text PDFJ Clin Densitom
January 2025
Department of Physical Education, Faculty of Arts and Sciences, University of Balamand, El-Koura, Lebanon. Electronic address:
The main aim of the current study was to compare the effects of two strength training modalities (hypertrophy vs. contrast training) on bone health parameters, physical performance and quality of life in a group of subjects aged 60 and above with low skeletal muscle mass index (SMI). 45 older adults voluntarily participated in this study, but only 41 (22 women and 19 men) completed it.
View Article and Find Full Text PDFSci Bull (Beijing)
January 2025
Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Hubei Provincial Engineering Research Center of Emerging Functional Coating Materials, School of Resource and Environmental Sciences, Wuhan University, Wuhan 430079, China. Electronic address:
The discontinuous fiber reinforced hydrogels are easy to fail due to the fracture of the fiber matrix during load-bearing. Here, we propose a novel strategy based on the synergistic reinforcement of interconnected natural fiber networks at multiple scales to fabricate hydrogels with extraordinary mechanical properties. Specifically, the P(AA-AM)/Cel (P(AA-AM), poly(acrylic acid-acrylamide); Cel, cellulose) hydrogel is synthesized by copolymerizing AA and AM on a substrate of paper with an interconnected hollow cellulose microfiber network.
View Article and Find Full Text PDFPolymers (Basel)
January 2025
N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russia.
In this work, the fracture mechanism of winding carbon-fiber-reinforced plastics (CFRPs) based on epoxy matrices reinforced by polysulfone film was investigated. Two types of polymer matrices were used: epoxy oligomer (EO) cured by iso-methyltetrahydrophthalic anhydride (iso-MTHPA), and EO-modified polysulfone (PSU) with active diluent furfuryl glycidyl ether (FGE) cured by iso-MTHPA. At the winding stage, the reinforcing film was placed in the middle layer of the CFRP.
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