Influence of Presintering Parameters on the Mechanical Properties of Presintered Dental Zirconia Block

Amat, Noor Faeizah; Raji, Shari Lawuo; Muchtar, Andanasuti; Amril, Muhammad Sufiyan; Ghazali, Mariyam Jameelah; Yahaya, Norziha

doi:10.30880/ijie.2018.10.05.011

Cited by 4 publications

(4 citation statements)

References 9 publications

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“…Material removal rate depends on a number of factors such as tool grit size, tool design, tool sequence and the type of material, its surface hardness and surface roughness [60]. As the milling tools have been standardized in the present study, the variation in the tool penetration rates between the ceramic groups could be attributed to the differences in the mechanical properties of the investigated ceramics such as hardness, toughness and their related brittleness index [24,61,62]. The pre-crystallized IPS CAD with 40% lithium metasilicate interlocked platelet crystals of low aspect ratio in its glass matrix with brittleness index of 2.5~2.9 µm -1/2 and hardness of 6~9 GPa is a well-known machinable ceramic.…”

Section: Tool Penetration Rates and Edge Chippingmentioning

confidence: 92%

Machinability of Zirconia Toughened Mica Glass Ceramics for Dental Restorations

Gali¹,

Suresh

2020

BDS

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Objective: For a dental material to be machinable for CAD/CAM technology, it must offer convenient machining, under a given set of cutting conditions. Quantitative evaluation of machinability has been assessed in literature through various parameters such as tool wear, penetration rates, surface roughness, cutting force and power. A machinable ceramic will typically demonstrate a higher tool penetration rate with signs of reduced diamond tool wear and edge chipping. The purpose of this in vitro study was to evaluate the feasibility of machining an experimental ceramic, 20 wt.% zirconia reinforced mica glass ceramics (G20Z) for indirect dental restorations and compare the tool penetration rates of G20Z to commercially available dental ceramics, Presintered Zirconia (PSZ) and IPS emax CAD. Material and Methods: Precursors of base glass (SiO2 -Al2O3 -K2O -MgO-B2O3 -F) were melted at 15000C for 2 h in a platinum crucible and quenched in deionised water. The glass frit was ball milled with 20 wt. % YSZ (G20Z) and subject to two stage heat treatment in a muffle furnace. Specimens of G20Z (12 X 2 mm) were evaluated for their feasibility of machining under varying spindle speed, depth of cut, and feed rates. Influence of depth of cut, spindle speed and feed rate (vc=8000-16000 rpm, d=0.4-0.8 mm, f=0.1- 0.3 mm/tooth) on cutting forces, material response, surface roughness and tool wear were investigated. Tool penetration rates, tool wear and margin chipping were also evaluated and compared with Pre-sintered Zirconia (PSZ) and e.max CAD in a custom dental milling surveyor at 30,000 rpm with a load of 0.98 N under water lubrication for 6 min. Tool penetration rates were calculated as the ratio of length of cut and milling time with a measuring microscope and scanning electron microscope was used for tool wear and edge chipping. ANOVA and Tukey Kramer tests were used for statistically comparing the means of each group. Results: Spindle speed and feed rate play a significant role in influencing surface roughness, thrust force, cutting forces and tool wear. Penetration rates of G20Z (0.32 ±0.12 mm/min) was significantly greater than PSZ (0.26 ±0.06 mm/min) and IPS e.max CAD (0.21 ±0.05 mm/min). SEM observations reveal tool abrasion and edge chipping regardless of the ceramic type. Conclusion: High spindle speeds delivers low cutting forces with an average surface roughness of 1.61 µm, with abrasive wear of the tool insert and brittle fracture of zirconia mica glass ceramic composites. G20Z with its machinable nature demonstrates greater tool penetration rates than PSZ and IPS e.max CAD. Tool wear and edge chipping is seen in all the investigated ceramics. Keywords Machinability, Dental Ceramics, Mica Glass-Ceramics, Dental Zirconia, Tool penetration rates.

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Section: Tool Penetration Rates and Edge Chippingmentioning

confidence: 92%

Machinability of Zirconia Toughened Mica Glass Ceramics for Dental Restorations

Gali¹,

Suresh

2020

BDS

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“…29 When zirconia is added to metal oxides, including magnesium oxide (MgO), calcium oxide (CaO), and yttrium oxide (Y 2 O 3 ), it generates high molecular stability. 30 Nanomaterials are excellent prospects for various applications in research and industry due to their unique characteristics and capabilities. 31 Magnesium oxide is one of the most valuable materials in this sector because of its high melting point, catalytic characteristics, nanocomposite for dental types of cement, 32 and other qualities.…”

Section: Magnesium Oxide As Biomaterials In Dentistrymentioning

confidence: 99%

Application of Magnesium Oxide Nanoparticles in Dentistry: A Literature Review

Sharifian,

Loghmani,

Nayyerain

et al. 2023

European Journal of General Dentistry

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Magnesium oxide (MgO) nanoparticles' biocompatibility and degraded by-products are the two most important factors that make this material preferable in dental care. Their specific characteristics, such as antibacterial action against cariogenic microbes, are potential antibacterial agents for dental applications. This paper investigates the properties of MgO in dentistry and sets the groundwork for future research. Electronic databases, including PubMed/Medline, Scopus, Google Scholar, and scientific-research journals of domestic universities were reviewed from 1972 to 2022, and all the relevant papers were surveyed. After a search in electronic databases, 60 articles were involved, and the needed details were extracted. The biochemical features and application of magnesium oxide nanoparticles (MgONPs) in dentistry and new fields have been discussed in detail. Nanoparticles (NPs) may provide a unique method for treating and preventing dental infections. MgO nanoparticles are a good choice in several fields because their unique properties, such as antibacterial activity against cariogenic microorganisms, make them ideal antibacterial agents for dental applications.

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“…Sintering causes a volume reduction, a decrease in roughness and pore volume (ref. [ 24 , 25 , 26 ]), and the transformation from the monoclinic to the tetragonal phase [ 27 ]. In order to achieve a complete phase transformation and, at the same time, minimize restraint stresses in the cross-section of the restoration, the heating and cooling rate [ 28 ] as well as the holding time during the re-sintering process have to be controlled.…”

Section: Introductionmentioning

confidence: 99%

Influence of Manufacturing Regimes on the Phase Transformation of Dental Zirconia

et al. 2021

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Background: The influence of typical manufacturing regimes for producing fixed dental prostheses (FDPs) from yttria partly-stabilized zirconia polycrystals (3Y/4Y/5Y-TZP) on the phase composition is quantified. Methods: Fixed dental prostheses (FDPs) were designed using a CAD process and machined from different Y-TZP blanks from two manufacturers differing in yttria contents. Subsequent to sintering, the FDPs were glaze fired and air-blasted using alumina particles. Phase composition was determined with X-ray diffraction and quantified with Rietveld refinement. Results: The blanks from VITA Zahnfabrik (VITA YZ HT, VITA YZ ST, VITA YZ XT) and Dental Direct (DD Bio ZX2, DD cube ONE, DD cube X2) featured a rhombohedral portion with rather small crystallites and a small monoclinic portion for 3Y/4Y-TZPs, which increased after machining and disappeared after sintering. Glaze firing and air-blasting with alumina particles had no significant influence on the phase composition. Conclusion: The phase history of dental zirconia is revealed, which may have implications on further processing and aging of the FDP (e.g., low temperature degradation) in mouth.

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Influence of Presintering Parameters on the Mechanical Properties of Presintered Dental Zirconia Block

Abstract: The zirconia nanopowder used in this study was 3YSZ (Inframat Advanced Materials, USA), which presents a specific surface area of 30-60 m 2 /g. The

Cited by 4 publications

References 9 publications

Machinability of Zirconia Toughened Mica Glass Ceramics for Dental Restorations

Machinability of Zirconia Toughened Mica Glass Ceramics for Dental Restorations

Application of Magnesium Oxide Nanoparticles in Dentistry: A Literature Review

Influence of Manufacturing Regimes on the Phase Transformation of Dental Zirconia

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