Factors Affecting the Wear Behavior of Monolithic Zirconia and the Antagonists: Literature Review

2020 ◽  
Vol 2 (1) ◽  
pp. 4-11
Author(s):  
Marcia Borba ◽  
Paula Benetti ◽  
Giordana P. Furini ◽  
Kátia R. Weber ◽  
Tábata M. da Silva

Background: The use of zirconia-based ceramics to produce monolithic restorations has increased due to improvements in the optical properties of the materials. Traditionally, zirconiabased ceramics were veneered with porcelain or glass-ceramic and were not directly exposed to the oral environment. Therefore, there are several doubts regarding the wear of the monolithic zirconia restoration and their antagonists. Additionally, different surface treatments are recommended to promote a smooth surface, including glaze and several polishing protocols. To support the correct clinical application, it is important to understand the advantages and limitations of each surface treatment. Objective: The aim of this short literature review is to investigate the factors that may affect the wear of monolithic zirconia restorations in service and their antagonists. Methods: Pubmed/Medline database was accessed to review the literature from a 10-year period using the keywords: zirconia, monolithic, prosthesis, wear. Both clinical and in vitro studies were included in the review. Results: Studies investigated the effect of several surface treatments, including grinding with diamond- burs, polishing and glazing, on the surface roughness, phase transformation and wear capacity of monolithic zirconia. The wear behavior of monolithic zirconia was frequently compared to the wear behavior of other ceramics, such as feldspathic porcelain, lithium disilicate-based glassceramic and leucite-reinforced glass-ceramic. Human tooth, ceramics and resin composites were used as antagonist in the investigations. Only short-term clinical studies are available (up to 2 years). Conclusion: Literature findings suggest that zirconia monolithic restorations are wear resistant and unlikely to cause excessive wear to the antagonist, especially when compared to feldspathic porcelain and glass-ceramics. Monolithic zirconia should be polished rather than glazed. Yet, none of the polishing systems studied was able to completely restore the initial surface conditions of zirconia after being adjusted with burs. More clinical evidence of the antagonist tooth wear potential of monolithic zirconia is needed.

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 160 ◽  
Author(s):  
Roxana-Diana Vasiliu ◽  
Sorin-Daniel Porojan ◽  
Mihaela-Ionela Bîrdeanu ◽  
Ion-Dragoș Uțu ◽  
Liliana Porojan

Dental ceramic restorations are widely used in restorative dentistry. However, these restorations can be affected once cemented in the oral cavity by several factors. How can conventional surface treatments, such as glazing and mechanical polishing, diminish the effects of aging? The purpose of this in vitro study was to evaluate the effect of thermocycling and conventional surface treatments on the surface roughness and microhardness of three types of glass-ceramics by using a profilometer, scanning electron microscopy (SEM), atomic force microscopy (AFM), and a microhardness tester. Three types of ceramic systems (zirconia reinforced lithium silicate glass-ceramic, lithium disilicate glass-ceramic, and feldspathic glass-ceramic) (n = 48) were prepared. The samples were subjected to thermocycling for 10,000 cycles. Surface roughness was evaluated numerically using a profilometer and visually by using SEM and AFM. Microhardness was performed using a microhardness tester. The data were interpreted using the ANOVA test, and the results were correlated using Pearson’s correlation formula (r). Significant differences were found before and after thermocycling for the Ra (p < 0.01) and Rz (p < 0.05) parameters. As well, differences between glazed and polished surfaces were significant before and after thermocycling for surface roughness and microhardness (p < 0.05). A correlation was made between average surface roughness and microhardness (r = −460) and for the maximum surface roughness and microhardness (r = −606). Aging increases the roughness and decreases in time the microhardness. The tested ceramic systems behaved differently to the aging and surface treatments. Surface treatments had a significant impact on the microhardness and surface characteristics. The glazed groups were reported with higher surface roughness and lower microhardness when compared to the polished groups before and after thermocycling. The measuring roughness techniques determine the scale-dependent values for the Ra (Sa) and Rz (Sq) parameters. Thermocycling almost doubled the surface roughness for all the tested samples. Microhardness decreased only for the Celtra glazed samples. Nano-roughness increased the values for Vita and slightly for Emax. Thermocycling had little effect on Emax ceramic and a more significant impact on Celtra Press ceramic.


Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 381 ◽  
Author(s):  
Roxana-Diana Vasiliu ◽  
Sorin Daniel Porojan ◽  
Mihaela Ionela Bîrdeanu ◽  
Liliana Porojan

Dental ceramic restorations are widely spread nowadays due to their aesthetics and biocompatibility. In time, the colour and structure of these ceramic materials can be altered by aging processes. How does artificial aging affect the optical and surface roughness of ceramics? This study aims to assess the effect of thermocycling, surface treatments and microstructure upon translucency, opalescence and surface roughness on CAD-CAM and heat-pressed glass-ceramic. Forty-eight samples (1.5 mm thickness) were fabricated from six types of A2 MT ceramic: heat-pressed and milled glass-ceramic (feldspathic, lithium disilicate and zirconia reinforced lithium silicate). The samples were obtained respecting the manufacturer’s instructions. The resulted surfaces (n = 96) were half glazed and half polished. The samples were subjected to thermocycling (10,000 cycles) and roughness values (Ra and Rz), colour coordinates (L*, a*, b*) and microstructural analyses were assessed before and after thermocycling. Translucency (TP) and opalescence (OP) were calculated. Values were statistically analysed using ANOVA test (one way). TP and OP values were significantly different between heat-pressed and milled ceramics before and also after thermocycling (p < 0.001). Surface treatments (glazing and polishing) had a significant effect on TP and OP and surface roughness (p < 0.05). The heat-pressed and milled zirconia reinforced lithium silicate glass-ceramic experienced a loss in TP and OP. Ra and Rz increased for the glazed samples, TP and OP decreased for all the samples after thermocycling. Microstructural analyse revealed that glazed surfaces were more affected by the thermocycling and especially for the zirconia reinforced lithium silicate ceramic. Optical properties and surface roughness of the chosen ceramic materials were affected by thermocycling, surface treatments and microstructural differences. The least affected of the ceramics was the lithium disilicate ceramic heat-pressed polished and glazed.


2006 ◽  
Vol 309-311 ◽  
pp. 325-328 ◽  
Author(s):  
Gültekin Göller ◽  
Ipek Akin ◽  
A. Kahraman ◽  
Erdem Demirkesen ◽  
M. Urgen

In this study; in-vitro bioactivity characterization of machinable glass-ceramics having 85 wt% sodium mica (NaMg3AlSi3O10F2) and 15 wt% fluoroapatite has been carried out. Two different heat treatment procedures are applied to the machinable glass-ceramics. The first one is nucleation at 610°C for 2 hours and crystallization at 1000°C for 3 hours and the second is nucleation at 610°C for 2 hours and crystallization at 1000°C for 4 hours. It is observed that increasing the crystallization time to 4 hours resulted in the increasing the formation of hydroxyapatite layer on surface. According to the microstructural investigations, the morphology of the precipitated crystals are different. In addition, the speed of the precipitation of hydroxyapatite is higher in glass-ceramic B than A. Thin film XRD analysis supports these results.


2006 ◽  
Vol 309-311 ◽  
pp. 289-292
Author(s):  
Ruth D. Goodridge ◽  
Chikara Ohtsuki ◽  
Masanobu Kamitakahara ◽  
David J. Wood ◽  
Kenny W. Dalgarno

The feasibility of processing glass-ceramics using the layer manufacturing technique, selective laser sintering (SLS), to produce parts with suitable biological and mechanical properties for use in bone replacement applications, has been investigated. Glass-ceramics derived from glasses based on several different systems have been considered. Initial experiments using an apatite-mullite glass-ceramic (4.5SiO2⋅3Al203⋅1.6P2O5⋅3CaO⋅2CaF2) demonstrated the ability to process glass-ceramic materials using this technique, creating parts with a strength similar to that of cancellous bone, and a porous structure that was shown in vivo to be suitable for the ingrowth of bone. Concerns over the inability of the apatite-mullite material to form an apatite layer on its surface when soaked in a simulated body fluid (SBF) has led to the development of Al2O3-free glasses based on the systems (50-x)CaO⋅45SiO2⋅5P2O5⋅xCaF2 and (48-x)CaO⋅45SiO2⋅5P2O5⋅2CaF2⋅xNa2O. These materials have demonstrated good in vitro bioactivity, and therefore have good potential as candidates for processing by an indirect SLS method for the production of custom-made bone implants.


2013 ◽  
Vol 834-836 ◽  
pp. 301-304
Author(s):  
Jian An Liu ◽  
Xue Na Yang ◽  
Mei Mei Zhang

A novel biphasic material has been synthesized from a melt-derived bioactive glass (45S5) and a glass-ceramic obtained from a melt-derived magnetic glass-ceramics for hyperthermia application. The biphasic material obtained from a mixture 1:1 of these components. The phase composition was investigated by XRD. The magnetic property was measured by VSM. The in vitro bioactivity was investigated by simulated body fluid (SBF) soaking experiment. The glass-ceramic shows magnetic behavior and bioactive, useful for hyperthermia.


2015 ◽  
Vol 804 ◽  
pp. 147-150
Author(s):  
Pratthana Intawin ◽  
Kamonpan Pengpat ◽  
Wilaiwan Leenakul ◽  
Tawee Tunkasiri

In this research, the effects of sintering temperatures on structural and bioactivity in BaFe12O19 (BF) /P2O5-CaO-Na2O bioactive glass ceramics were investigated. The BF/P2O5-CaO-Na2O bioactive glass ceramics were fabricated under various sintering temperatures in a range of 550-700 oC. X-ray diffraction (XRD) technique and the scanning electron microscopy (SEM) are used to characterize phase and microstructure. The studied samples were evaluated for mechanical properties by hardness testing. Moreover, the bioactivities of studied samples were studied by using simulated body fluid (SBF) in vitro. It was found that, the sintering temperatures are the most influential parameter on microstructure and mechanical properties of the bioactive glass ceramics. The highest density of studied ceramics was found in the sample sintered at 700 oC. The microstructural properties of the studies samples were investigated and the results were then correlated with the characteristics of sintering temperature as well as the microstructure of the bioactive glass ceramic. Moreover, the covering of bone-like apatite layer on the surface sample after a 7 day immersion in SBF suggested that the BF/P2O5-CaO-Na2O glass ceramics have acceptable bioactivities.


Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 540 ◽  
Author(s):  
Elisa Fiume ◽  
Carla Migneco ◽  
Enrica Verné ◽  
Francesco Baino

Bioactive sol-gel glasses are attractive biomaterials from both technological and functional viewpoints as they require lower processing temperatures compared to their melt-derived counterparts and exhibit a high specific surface area due to inherent nanoporosity. However, most of these materials are based on relatively simple binary or ternary oxide systems since the synthesis of multicomponent glasses via sol-gel still is a challenge. This work reports for the first time the production and characterization of sol-gel materials based on a six-oxide basic system (SiO2–P2O5–CaO–MgO–Na2O–K2O). It was shown that calcination played a role in inducing the formation of crystalline phases, thus generating glass-ceramic materials. The thermal, microstructural and textural properties, as well as the in vitro bioactivity, of these sol-gel materials were assessed and compared to those of the melt-derived counterpart glass with the same nominal composition. In spite of their glass-ceramic nature, these materials retained an excellent apatite-forming ability, which is key in bone repair applications.


2013 ◽  
Vol 19 (2) ◽  
pp. 231-239 ◽  
Author(s):  
Nima Nabian ◽  
Maedeh Delavar ◽  
Mahmood Rabiee ◽  
Mohsen Jahanshahi

The paper reports the first attempt at changing cooling treatment of synthesizing method in order to investigate its effect on the physical properties of sol-gel derived nano bioactive glass-ceramic in the system 58SiO2-33CaO-9P2O5 (wt.%). We hypothesized that the method of cooling may affect the properties of nano bioactive glass-ceramic. To test this hypothesis, two different method of cooling treatment was applied after calcinations in synthesizing method. Both quenched and unquenched nano bioactive glass-ceramics were soaked in Ringer?s solution with bovine serum albumin (BSA) for bioactivity evaluation. The obtained samples were analyzed for their composition, crystalinity and morphology through X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), surface electron microscope (SEM) and transmission electron microscope (TEM). The SEM images showed that the morphology of nano bioactive glass-ceramics was completely changed by quenching process. Results of in vitro bioactivity evaluation revealed that the unquenched attains faster apatite formation ability than the quenched sample. Other properties of these two morphologically different nano bioactive glass-ceramics were strongly discussed.


Coatings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 580 ◽  
Author(s):  
Gaoqi Wang ◽  
Yunkai Li ◽  
Shouren Wang ◽  
Xuefeng Yang ◽  
Yujing Sun

As a veneering porcelain coating of dental prosthesis, two-body and three-body wear behavior of dental glass-ceramic with the main crystalline phase of fluorapatite has not been comprehensively studied. In this work, a self-made fluorapatite glass-ceramic was synthesized and the mechanical and tribological performances of the glass-ceramic were tested, comparing with a commercial feldspathic glass-ceramic. The friction and wear experiments were performed between disk-shaped glass-ceramics and natural teeth in two-body (dry, water, saliva) and three-body (slurry) modes, respectively. Results showed that good mechanical properties of fluorapatite glass-ceramic can be achieved by the sintering process. In both two-body and three-body modes, the fluorapatite glass-ceramic had a smaller friction coefficient and wear rate and caused less damage on antagonistic teeth than the feldspathic glass-ceramic. The greater mechanical properties give fluorapatite glass-ceramic a better wear resistance and reduce the adhesive wear.


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