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Sindel, J.; Petschelt, Anselm; Grellner, F.; Dierken, C.; Greil, Peter

doi:10.1023/a:1008812929476

Cited by 55 publications

(10 citation statements)

References 3 publications

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“…Studies on subsurface damage in feldspathic porcelain and Dicor MGC glass ceramic revealed microcracking, chipping, crushing and crumbling. The response of Dicor MGC, a mica based glass ceramic, with CEREC-1 CAD CAM system and a high speed diamond wheel showed similar material removal mechanism of brittle fracture and micro-chipping to the experimental zirconia reinforced mica glass ceramic in the present study [58].…”

Section: Multiple Comparison Of Mean Differences Between Different Grsupporting

confidence: 72%

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: Multiple Comparison Of Mean Differences Between Different Grsupporting

confidence: 72%

Machinability of Zirconia Toughened Mica Glass Ceramics for Dental Restorations

Gali¹,

Suresh

2020

BDS

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“…Due to the brittle nature of ceramics, it is very likely that it will be more affected than metal [44]. Subcritical ceramic surface damage could develop in the form of surface microfractures, chipping defects, and altered surface quality [51, 52] and could constitute a point for crack propagation within the restoration under occlusal forces [52]. The extent of the damage is dependent on the material of the workpiece [53] and ranges from 15 to 60 μ m [54–56].…”

Section: Computer-aided Production Streamsmentioning

confidence: 99%

Trends in Computer-Aided Manufacturing in Prosthodontics: A Review of the Available Streams

Abduo

Lyons

Bennamoun

2014

International Journal of Dentistry

278

220

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In prosthodontics, conventional methods of fabrication of oral and facial prostheses have been considered the gold standard for many years. The development of computer-aided manufacturing and the medical application of this industrial technology have provided an alternative way of fabricating oral and facial prostheses. This narrative review aims to evaluate the different streams of computer-aided manufacturing in prosthodontics. To date, there are two streams: the subtractive and the additive approaches. The differences reside in the processing protocols, materials used, and their respective accuracy. In general, there is a tendency for the subtractive method to provide more homogeneous objects with acceptable accuracy that may be more suitable for the production of intraoral prostheses where high occlusal forces are anticipated. Additive manufacturing methods have the ability to produce large workpieces with significant surface variation and competitive accuracy. Such advantages make them ideal for the fabrication of facial prostheses.

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“…According to Sindel et al [24] CAD/CAM machining of zirconia induces compressive stresses on the surface of the material. After machining of the material, the sintering process that follows partially heals microflaws and cracks created during machining [25].…”

Section: Discussionmentioning

confidence: 99%

The Influence of Sandblasting and Aging on Y-TZP Ceramic During Static and Dynamic Loading

Ziozios¹

2017

Ceramics - Silikaty

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loss modulus and tanδ were investigated, while surface characterization was performed through Scanning Electron Microscopy (SEM) and X-Ray Diffraction Analysis (XRD). Sandblasting as well as the aging environment caused a raise of zirconia's shear modulus, Young's modulus and storage modulus. The most prominent increase, in these parameters was observed when both treatments where combined. Under the limitations of this in-vitro study it can be concluded that the proposed sandblasting and aging procedures do not impair the mechanical properties of zirconia ceramics, as long as the amount of monoclinic zirconia content is kept under low values, capable to induce the transformation toughening mechanism.

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Cited by 55 publications

References 3 publications

Machinability of Zirconia Toughened Mica Glass Ceramics for Dental Restorations

Machinability of Zirconia Toughened Mica Glass Ceramics for Dental Restorations

Trends in Computer-Aided Manufacturing in Prosthodontics: A Review of the Available Streams

The Influence of Sandblasting and Aging on Y-TZP Ceramic During Static and Dynamic Loading

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