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Introduction The evolution of computer-aided design/computer-aided manufacturing (CAD/CAM) systems has heightened the significance of digital models in dentistry, particularly for fabricating prostheses like inlays, crowns, and bridges. While digital dentistry offers enhanced speed and precision, the initial investment in intraoral scanners may pose a barrier for some clinicians. Extraoral or lab scanners, however, offer a viable alternative, reducing laboratory time and providing accurate prostheses fit, though challenges such as reflective surfaces and availability of scanning sprays persist, impacting scanning quality and operator technique. Optical scanning using laboratory scanners is a routine practice in today's age of digital dentistry. Often these require powder opacification to record fine details. There are numbered studies on the accuracy of scanning sprays. Materials and methods Ten casts, poured with type 4 dental stone (Elite Rock, Zhermack, Italy) with single implants, were used for the purpose of this study. Each cast was scanned by two different operators, using both mediums. It was scanned using an extraoral scanner (E4, 3Shape, Copenhagen, Denmark). Operator A used easy scan (Alphadent, Korea), followed by zirconia dust (Upcera, Guangdong, China), whereas operator B used zirconia dust first. Digital models within each group were superimposed individually to measure precision. Results Easy scan operator 1 and zirconia dust operator 1 differ by 0.16000 (p = 0.0802). In scenario 2, easy scan operator 2 and zirconia dust operator 2 differ by 0.21900 (p = 0.0212) . Operator type significantly affects performance, emphasizing the need to account for operator variability in relevant contexts. The trueness values obtained for zirconia dust and easy scan among both operators were statistically insignificant. Conclusion Zirconia dust can be reliably used for extraoral scanning of abutments in place of optical scanning sprays.
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http://dx.doi.org/10.7759/cureus.61633 | DOI Listing |
Cureus
July 2024
Prosthodontics, Sri Ramaswamy Memorial (SRM) Kattankulathur Dental College and Hospital, Chengalpattu, IND.
Aim The aim of this study is to evaluate and compare the microhardness and polymerization shrinkage of polymethyl methacrylate reinforced with residual zirconia. Materials and methods A total of 360 resin samples were fabricated, with dimensions of 12 mm × 12 mm × 3 mm and 12 mm × 8 mm × 6 mm. Zirconia dust (40% by weight) was added to 180 of these samples.
View Article and Find Full Text PDFCureus
June 2024
Prosthodontics, Saveetha Dental College, Chennai, IND.
Introduction The evolution of computer-aided design/computer-aided manufacturing (CAD/CAM) systems has heightened the significance of digital models in dentistry, particularly for fabricating prostheses like inlays, crowns, and bridges. While digital dentistry offers enhanced speed and precision, the initial investment in intraoral scanners may pose a barrier for some clinicians. Extraoral or lab scanners, however, offer a viable alternative, reducing laboratory time and providing accurate prostheses fit, though challenges such as reflective surfaces and availability of scanning sprays persist, impacting scanning quality and operator technique.
View Article and Find Full Text PDFJ Prosthet Dent
December 2023
Professor and Chairman, Department of Dental Laboratory Science, College of Health Sciences, Catholic University of Pusan, Busan, Republic of Korea. Electronic address:
Statement Of Problem: The dry processing of zirconia has the disadvantage of dust dispersal during milling; thus, wet milling may be preferable. However, research on the mechanical properties of dental zirconia milled under different conditions and sintered at different temperatures is lacking.
Purpose: The purpose of this in vitro study was to evaluate changes in the mechanical properties of zirconia specimens after milling under dry and wet conditions at different sintering temperatures.
Sci Total Environ
March 2021
Departamento de Geología, Universidad de Sonora, Rosales y Encinas, Hermosillo, Sonora 83000, Mexico.
Using catalytic converters is one of the most effective methods to control vehicle emissions. A washcoat of cerium oxide-zirconia (CeO-ZrO) has been used to enhance the performance of the catalytic converter device. To date, the prevalence of this material in the environment has not been assessed.
View Article and Find Full Text PDFJ Hazard Mater
July 2020
School of Safety Science and Emergency Management, Wuhan University of Technology, Wuhan 430070, China.
Flame propagation characteristics of wood dust deflagration and suppression mechanism of ultrafine powders are investigated systematically. The deflagration reaction intensity of wood dust increases firstly and then decreases with the increase in dust cloud concentration. This is due to factors such as oxygen supply, positive feedback among flame characteristic parameters.
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