Objective: The aim of this study was to microstructurally characterize and to make comparisons of the physical properties of sintered dental porcelains prepared by mixing with distilled water and with their modeling liquid.
Methods: Six commercial porcelain powders: IPS Classic (Ivoclar Vivadent AG, Schaan, Liechtenstein), IPS d.SIGN (Ivoclar Vivadent AG), IPS InLine (Ivoclar Vivadent AG), Vita VMK95 (Vita Zahnfabrik, Bad Sackingen, Germany), Vita OMEGA 900 (Vita) and Ceramco III (Ceramco-Dentsply, Burlington, NJ, USA) were used as starting powders. Following particle size and BET analyses of starting powders, each porcelain powder was mixed with distilled water and with its own modeling liquid. Disc specimens were sintered in accordance with each manufacturer's instructions. Specimens were characterized using X-ray diffraction (XRD), optical microscopy and SEM analysis and their physical properties such as bulk density, microhardness and biaxial flexural strength were determined.
Results: The sintered dental porcelains premixed with modeling liquid had density, biaxial flexural strength and microhardness values slightly higher than those premixed with distilled water. Mixing with distilled water and modeling liquid caused statistically significant differences between the density values of Vita VMK 95 and microhardness values of IPS d.SIGN and IPS InLine. Characterization investigations (XRD and SEM) revealed the coexistence of the tetragonal leucite (1-3 microm) and hexagonal fluorapatite crystals (0.4-1.2 microm) in a feldspathic glassy matrix in the microstructure of IPS d.SIGN and only leucite crystals (3-6 microm) in the microstructures of other porcelains.
Significance: Mixing the porcelain powders with distilled water or modeling liquid prior to sintering has no effect on the resultant sintered crystalline microstructure. On the other hand, significant differences exist between the physical properties of some porcelains.
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http://dx.doi.org/10.1016/j.dental.2005.08.007 | DOI Listing |
Glob Chang Biol
January 2025
Geography and Environmental Science, University of Southampton, Southampton, UK.
The concepts of planetary boundaries are influential in the sustainability literature and assist in delineating the 'safe operating spaces' beyond which critical Earth system processes could collapse. Moving away from our current trajectory towards 'hothouse Earth' will require knowledge of how Earth systems have varied throughout the Holocene, and whether and how far we have deviated from past ranges of variability. Such information can inform decisions about where change could be resisted, accepted or where adaptation is inevitable.
View Article and Find Full Text PDFNarra J
December 2024
Department of Tropical Biology, Faculty of Biology, Universitas Gadjah Mada, Yogyakarta, Indonesia.
Dengue hemorrhagic fever (DHF) is a major health concern in tropical and subtropical countries. Indonesia has DHF cases perennially every year. On the other hand, Indonesia is abundant with seaweed ), which can be found across its seashore.
View Article and Find Full Text PDFClin Oral Investig
January 2025
Department of Pedodontics, Faculty of Dentistry, Erciyes University, 38039, Kayseri, Türkiye.
Objectives: This study evaluates the effect of different irrigation solutions for postoperative pain in the regenerative endodontic treatments (RET) of necrotic teeth with open apex.
Materials And Methods: This study included necrotic, deeply carious lower molars of 42 patients. Access cavities of the teeth were opened and working lengths were measured at the first visit.
Sci Rep
January 2025
Dental Students, College of Medicine and Dentistry, Riyadh Elm University, Riyadh, KSA, Saudi Arabia.
Objective To evaluate the stain resistance and color stability of four Clear aligners (CA) brands against various beverages at different intervals, along with assessing the elaboration of cleaning agents. Methods In a strictly controlled lab environment, 48 CAs from four different companies (Invisalign, EON, Clear Cap, and K clear) were immersed for seven days in six different beverages based on their pH (Pepsi, orange juice, milk, coffee, and black tea), as well as a control solution (distilled water). The VITA Easy-Shade compact colorimeter used the Commission International lightening L*a*b* color scheme to evaluate the color change of the aligners at four intervals.
View Article and Find Full Text PDFSci Total Environ
January 2025
Social Development and Health Promotion Research Center, Health Policy and Promotion Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran. Electronic address:
Nowadays, polyethylene terephthalate (PET) bottles are widely used for packaging drinks and food. However, concerns have been raised about the possible migration of harmful chemicals, particularly phthalates, from these containers into their contents. Therefore, this study investigates the effects of sunlight exposure and PET bottle reuse on phthalate migration, focusing on three common phthalates: bis(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), and benzyl butyl phthalate (BBP).
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