Effect of zirconia ceramic sintering condition on the precision of fit in dental restorations

Zirconia is the preferred material for dental restorations; however, dental restorations are usually affected by zirconia fractures due to chipping and delamination of the veneer ceramic. One effective solution for repairing chemically inert zirconia frameworks is to strongly chemically bond them with the composite resin via surface modification. Thus, the bonding strength between the zirconia and composite resin determines the performance of dental restoration. Herein, we investigate the shear bond strength between zirconia ceramic and two ceramic repair systems before and after thermal cycling based on different surface pretreatments, including air-abrasion and a novel silane coupling agent. When treated with combined sandblasting, novel silane and 10-methacryloyloxydecyl hydrogen phosphate act as a bonding agent for the zirconia surface, and the maximum shear bond strength achieves 27.5 MPa, as measured by a universal testing machine through the average of 16 separate measurements. The results show that the combined treatment resists the interface damage caused by expansion and contraction during thermal cycling. The long-term bond durability is due to the micro-mechanical bond force formed by resin and ceramic, and the chemical bonds of Zr-O-Si at the interface. Results indicate that selective pretreating the surface results in high bond strength between the zirconia and the composite resin, which is meaningful to optimize dental restoration.

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Surface Properties of Dental 3Y-TZP with Different Treatments

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.633.352 ◽

2014 ◽

Vol 633 ◽

pp. 352-356

Author(s):

Yi Hong Liu ◽

Yong Wang

Keyword(s):

Computer Aided Design ◽

Tetragonal Zirconia ◽

Optical Microscope ◽

Milling Process ◽

Machining Process ◽

Uniaxial Pressure ◽

Zirconia Ceramic ◽

Full Density ◽

Green Body ◽

Dental Restorations

The purpose of this study was to study the surface characteristics of the dental 3Y-TZP (3 mol% yttria stabilized tetragonal zirconia) ceramic treated by machining process and analysis what impact on the mechanical properties of the 3Y-TZP dental restorations. Dense core ceramic discs were made of 3Y-TZP. The samples were partially sintered to get part strength after uniaxial pressure moulding. The partially sintering green body could be treated by grinding, incising and milling and incising to simulate the CAD-CAM (computer aided design/computer aidedmanufacturing) process in dentistry. The partially sintering samples were then sintered to achieve full density. The dense sintered ceramics were also treated by grinding and incising to simulate the dental restorations adjusting process in dental clinic. The both surface of thespecimens were studied with an optical microscope and field emission SEM. Bulges were observed on the surface of the sample after uniaxial pressure moulding process. The defects due to partially sintered green body milling process were different from incising process in size and shape. Groves are observed on the surfaces of the samples after grinding process. The conclusions were that (i) machining of the final sintered dental 3Y-TZP ceramic brought more critical damage than the machining of partly-sintered green-bodies; (ii) the milling process ofthe partially sintered green-body brought less damage to the 3Y-TZP samples than the incising process.

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Dental restorations. Phosphate-bonded refractory die materials

10.3403/02049216u ◽

2015 ◽

Keyword(s):

Dental Restorations ◽

Die Materials

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Study of Electrochemical Behavior of Some Dental Alloys

Revista de Chimie ◽

10.37358/rc.18.6.6377 ◽

2018 ◽

Vol 69 (6) ◽

pp. 1598-1602

Author(s):

Alice Arina Ciocan Pendefunda ◽

Constanta Mocanu ◽

Doriana Agop Forna ◽

Cristina Iordache ◽

Elena Luca ◽

...

Keyword(s):

Oral Cavity ◽

Electrochemical Behavior ◽

Base Alloy ◽

Artificial Saliva ◽

Surface Condition ◽

Continuous Process ◽

Metal Alloys ◽

Alloy Surface ◽

Dental Alloys ◽

Dental Restorations

The purpose of the study is to investigate the electrochemical behavior of two dental alloys: palladium alloy (Palidor) and Ni-Cr alloy (Verasoft) in three types of artificial saliva. Determination of corrosion potential and recording of linear and cyclic polarization curves were performed with PGP201 potentiostat (VoltaLab 21- Radelkis Copenhagen. In order to study the modifications produced on the surface of the electrodes, a complex optical microscope MC 1 research type (IOR, Romania) was used, adapted to a digital camera, which was connected to a computer for the digital acquisition of images . Two metal alloys based on Ag-Pd and Ni-Cr were used for the experiments. The materials used came from different types of dental restorations removed from the oral cavity of the patients after a 5-15 years period. As corrosion environments, three artificial saliva were used: Fusayama, Afnor and Rondelli. The Pd-Ag dental alloy exhibits a very good corrosion resistance and the treatment in the Afnor saliva does not affect the surface of the alloy. Electrochemical behavior in Fusayama-Meyer�s saliva of the alloy surface results in a series of spots representing deposits of insoluble salts resulting from the oxidation process, while in the Rondelli saliva there is a series of small corrosion points on the alloy surface. The behavior of the Verasoft alloy in the Afnor and Rondelli saliva is similar; In both solutions, the potential breakthroughs are very close, but in Fusayama-Meyer�s saliva, the potential for initiation of corrosion points is very low (206 mV), a potential that can be encountered in the oral cavity. All metals and metal alloys, even the noble and semi-precious ones, are susceptible to corrosion, forming compounds with properties different from those of the metal or base alloy, which change their surface condition. Metallic dental restorations are permanently affected by the factors of the oral environment (physical-mechanical, chemical and biological), being subjected to a continuous process of degradation.

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EVALUATION OF DIFFERENT SURFACE CONDITIONING METHODS ON THE BOND STRENGTH OF ZIRCONIA CERAMIC TO A RESIN CEMENT

Egyptian Dental Journal ◽

10.21608/edj.2017.76432 ◽

2017 ◽

Vol 63 (4) ◽

pp. 3667-3672

Author(s):

Tarek Abdelrehim

Keyword(s):

Bond Strength ◽

Resin Cement ◽

Zirconia Ceramic ◽

Surface Conditioning

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Maximum Temperature Through a Yttrium Stabilized Zirconia Ceramic After Er,Cr:YSGG Laser Irradiation

Current Dentistry ◽

10.2174/2542579x02999200806160149 ◽

2020 ◽

Vol 02 ◽

Author(s):

Laurel Stringer ◽

Sarah Malley ◽

Darrell M. Hutto ◽

Jason A. Griggs ◽

Susana M. Salazar Marocho

Keyword(s):

High Speed ◽

Potential Method ◽

Maximum Temperature ◽

Zirconia Ceramic ◽

Tooth Pulp ◽

Control Group ◽

Stabilized Zirconia ◽

Significant Difference ◽

Power Setting ◽

Group A

Background: The most common approach to remove yttria stabilized zirconia (YSZ) fixed-dental prostheses (FDPs) is by means of diamond burs attached to a high-speed handpiece. This process is time-consuming and destructive. The use of lasers over mechanical instrumentation for removal of FDPs can lead to efficient and predictable restoration retrievability. However, the heat produced might damage the tooth pulp (>42˚C). Objective: The purpose of this study was to determine the maximum temperature (T) reached during the use of different settings of the erbium, chromium:yttrium-scandium-gallium-garnet Er,Cr:YSGG laser through a YSZ ceramic. Methods: YSZ slices (1 mm thick) were assigned into 7 groups. For the control group, a diamond bur was used to cut a 1 mm groove into the YSZ slices. For the 6 experimental groups, the laser was operated at a constant combination of 33% water and 66% air during 30 s with two different power settings (W) at three frequencies (PPS), as follows (W/PPS): 2.5/20, 2.5/30, 2.5/45, 4.5/20, 4.5/30, 4.5/45. The T through the YSZ slice was recorded in degrees Celsius by using a digital thermometer with a K thermocouple. Results: The median T of the control group was 26.5˚C. The use of 4.5 W resulted in the median T (˚C) of 44.2 at 20 PPS, 53.3 at 30 PPS, and 58.9 at 45 PPS, while 2.5 W showed 34.6, 31.6, and 25.0 at 20, 30, and 45 PPS, respectively. KruskalWallis one-way ANOVA showed that within each power setting, the T was similar. The high power and lowest frequency (4.5/20) showed no significant difference from the 2.5 W settings and the control group. Conclusion: The lower power setting (2.5 W) is a potential method for the use of the Er,Cr:YSGG laser to debond YSZ structures. The higher power (4.5 W) with high frequencies (30 and 45 PPS) is unsuitable.

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