Objectives: Due to its high fracture toughness ceria-stabilized ZrO(2)/Al(2)O(3) nanocomposite (Ce-TZP/A) could be superior to Y-TZP in clinical use. However, the compatibility to veneering ceramics is not yet investigated and therefore subject of this study.
Methods: Fracture strength and crazing resistance of veneered Ce-TZP/A frameworks (Nanozir, Matsushita Electric Works) were investigated in comparison to sintered and hipped Y-TZP (Hint-ELs). Frameworks were machined (HiCut, Hint-ELs), sintered where applicable (hiTherm, Hint-ELs), and veneered in a standardized procedure (Cerabien ZR, Noritake). Fracture strength of the crowns was assessed in a shear test (n=10). Biaxial flexural strength of the core materials was measured according to ISO 6872 (n=10). To assess the thermal compatibility between framework and veneer the coefficient of thermal expansion (CTE) of all materials was determined (n=3) and a crazing test carried out (n=12).
Results: Fracture strength was equal for crowns with Ce-TZP/A (866.6+/-132.1N) and sintered Y-TZP (904.5+/-168.2N), while crowns with hipped Y-TZP were significantly stronger (1380.6+/-253.2N) (Student's t-test, p<0.05). These values correlated with the biaxial flexural strength of the three core materials (Ce-TZP/A: 1238.0+/-200.0MPa, sintered Y-TZP: 1181.8+/-232.5MPa and hipped Y-TZP: 1521.8+/-163.8MPa). Failure of both hipped and sintered Y-TZP crowns occurred by chipping of the veneer or total fracture, while the Ce-TZP/A crowns predominantly failed by chipping of the veneer. In the crazing test both sintered and hipped Y-TZP performed slightly better than Ce-TZP/A. CTE's were as follows: Ce-TZP/A: 10.3microm/mK, sintered Y-TZP: 10.7microm/mK, hipped Y-TZP: 10.9microm/mK, and Cerabien ZR: 9.9microm/mK.
Significance: The CTE of the veneering ceramic has to be adjusted to Ce-TZP/A frameworks.
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http://dx.doi.org/10.1016/j.dental.2007.01.005 | DOI Listing |
J Clin Densitom
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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.
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January 2025
Advanced Glass and Glass Ceramic Research Laboratory, Department of Physics, University of Lucknow, Lucknow, 226007, India.
Recently, 3-D porous architecture of the composites play a key role in cell proliferation, bone regeneration, and anticancer activities. The osteoinductive and osteoconductive properties of β-TCP allow for the complete repair of numerous bone defects. Herein, β-TCP was synthesized by wet chemical precipitation route, and their 3-D porous composites with HBO and Cu nanoparticles were prepared by the solid-state reaction method with improved mechanical and biological performances.
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 PDFBackground: There has been an increase in both primary anatomic (aTSA) and reverse total shoulder arthroplasty (rTSA) over the last decade, with rates peaking for patients aged 75 years and older. Despite aTSA being the mainstay of treatment for patients with glenohumeral arthritis in the absence of rotator cuff insufficiency, there has been an upward trend of rTSA utilization in the elderly due to concerns about rotator cuff integrity, regardless of deformity. The purpose of this study is to evaluate outcomes including pain, function, range of motion, satisfaction, and complications in patients 80 years or older following primary anatomic and reverse total shoulder arthroplasty for osteoarthritis without full thickness rotator cuff tears.
View Article and Find Full Text PDFJ Mech Behav Biomed Mater
January 2025
School of Materials Science and Engineering, University of Jinan, Jinan, 250022, China. Electronic address:
Silicon nitride (Si₃N₄) ceramics exhibit excellent mechanical properties and biocompatibility, making them highly suitable for biomedical applications, particularly in implants. In this study, the mechanical properties and bioactivity of Si₃N₄ ceramics with varying amounts of Y₂O₃-Al₂O₃-SiO₂ sintering aids were investigated. Increasing the sintering additive content from 4 wt% to 8 wt% substantially improved the bulk density of the ceramics, leading to notable enhancements in mechanical properties.
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