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Dental Materials : Official Publication... May 2019To fully realize the range of indication and clinical advantages of the new multi-layered zirconias, a comprehensive understanding of their chemical composition,...
OBJECTIVES
To fully realize the range of indication and clinical advantages of the new multi-layered zirconias, a comprehensive understanding of their chemical composition, microstructure, low temperature degradation (LTD) resistance, and translucency properties is paramount.
METHODS
A zirconia system (Katana, Kuraray Noritake), including 3 distinct grades of multi-layered zirconias, was selected for study: Ultra Translucent Multi-layered zirconia (UTML), Super Translucent Multi-layered zirconia (STML), and Multi-layered zirconia (ML). For different materials and their individual layers, the chemical composition, zirconia phase fractions, and microstructure were determined by X-ray fluorescence (XRF), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM). Also, their resistance to LTD and translucency properties were characterized.
RESULTS
Our findings revealed no major differences amongst layers, but the 3 materials were very distinct-UTML: 5Y-PSZ (5 mol% yttria-partially-stabilized zirconia) with ˜75 wt% cubic content and a 4.05 (±0.85) μm average grain size, STML: 4Y-PSZ with ˜65 wt% cubic content and a 2.81 (±0.17) μm average grain size, and ML: 3Y-PSZ with <50 wt% cubic content and a 0.63 (±0.03) μm average grain size. After water aging at 120 °C for 12 h, greater monoclinic content was found in ML. UTML and STML did not show detectable monoclinic phase. The translucency was similar among layers, and also between UTML and STML, which were superior to ML.
SIGNIFICANCE
For each multi-layered zirconia grades, the layers are only differed in pigment types and contents, which yield remarkably natural shade gradients. Also, despite the significant compositional difference between STML and UTML, both materials showed similar translucencies.
Topics: Ceramics; Dental Materials; Materials Testing; Surface Properties; X-Ray Diffraction; Yttrium; Zirconium
PubMed: 30853208
DOI: 10.1016/j.dental.2019.02.017 -
Materials (Basel, Switzerland) Oct 2015Translucency of dental ceramics, esthetic posts and orthodontic brackets was reviewed. Translucency parameter () and contrast ratio () are generally used for... (Review)
Review
Translucency of dental ceramics, esthetic posts and orthodontic brackets was reviewed. Translucency parameter () and contrast ratio () are generally used for translucency evaluation. For the evaluation of translucency, two criteria such as the translucency of human teeth ( = 15-19, 1 mm thick) and the visual perceptibility threshold for the translucency difference (∆ > 0.07 or ∆ > 2) were used. In ceramics, translucency differences were in the perceptible range depending on the type of material and the thickness. However, variations caused by the difference in the required thickness for each layer by the material and also by the measurement protocols should be considered. As to the translucency of esthetic posts, a significant difference was found among the post systems. Translucency was influenced by the bracket composition and brand, and the differences by the brand were visually perceptible.
PubMed: 28793634
DOI: 10.3390/ma8115379 -
The Saudi Dental Journal Jul 2018To evaluate the effect of staining and bleaching on color and translucency of finished and unfinished nano-filled resin composite and giomer. Twenty specimens (ten...
To evaluate the effect of staining and bleaching on color and translucency of finished and unfinished nano-filled resin composite and giomer. Twenty specimens (ten finished + ten unfinished) were fabricated from each material, then an initial color and translucency measurement was taken. Specimens were stained in coffee for 48 h at 37 °C, rinsed and dried. After which the second color and translucency measurement was taken. After in-office bleaching with 40% HO Opalescence boost, a third color and translucency measurement was taken. CIE system was used for measuring color change and translucency. Two-way ANOVA and paired -test were used for statistical analysis at P ≤ 0.05. After staining, all specimens showed clinically acceptable color change ( ≤ 3.3) with no significant differences between groups. After bleaching, all specimens showed clinically unacceptable color change ( > 3.3) and significant differences between finished & polished and unfinished groups (P = 0.024). Nano-composites recorded significantly higher translucency than giomer (P = 0.000) except after bleaching. In addition, the translucency of unfinished groups were significantly higher than finished & polished groups (P = 0.001). The tested materials responded similarly to staining and bleaching. High concentration bleaching increased color change and reduced translucency. Finishing & polishing restorative materials improves their resistance to color change after bleaching, but it adversely affects translucency.
PubMed: 29942106
DOI: 10.1016/j.sdentj.2018.02.002 -
Dental Research Journal 2022The main drawbacks of zirconia are its high refractive index and opacity. This study aimed to assess the effect of sintering temperature on the translucency of Ivoclar...
BACKGROUND
The main drawbacks of zirconia are its high refractive index and opacity. This study aimed to assess the effect of sintering temperature on the translucency of Ivoclar e. max ZirCAD (IEZ), and White Peaks Symphony (WPS) zirconia blocks.
MATERIALS AND METHODS
In this experimental study, 30 IEZ and 30 WPS zirconia blocks measuring 10 mm × 10 mm × 1 mm were prepared and underwent sintering in three subgroups at 1440°C, 1500°C, and 1530°C. The specimens were then photographed against a black and a white background with a standard digital camera. The L*, a*, and b* color parameters were measured using Adobe Photoshop software, and translucency was calculated. Data were analyzed using one-way ANOVA and Tukey's test ( < 0.05).
RESULTS
In both the IEZ and WPS groups, the maximum and minimum translucency parameters were recorded in 1530°C and 1440°C subgroups, respectively. The difference in the mean translucency was significant among the three subgroups of each zirconia group ( < 0.001). The mean translucency of WPS zirconia was significantly higher than that of IEZ zirconia ( < 0.01), and maximum difference was noted at 1500°C sintering temperature.
CONCLUSION
Increasing the sintering temperature from 1440°C to 1530°C can significantly increase the translucency of IEZ and WPS zirconia blocks, and can be considered to improve the quality of zirconia restorations.
PubMed: 36426278
DOI: No ID Found -
Hua Xi Kou Qiang Yi Xue Za Zhi = Huaxi... Feb 2024This work aimed to evaluate the effect of speed sintering and low-temperature degradation on the translucency of high-translucent zirconia.
OBJECTIVES
This work aimed to evaluate the effect of speed sintering and low-temperature degradation on the translucency of high-translucent zirconia.
METHODS
The ST and TT specimens were randomly divided into two groups depending on the sintering process: conventional sintering and speed sintering. The sintered specimens were divided into three subgroups according to the aging time: aged for 0, 5, and 20 h. Chromatic parameters (L*, a*, and b* values) were measured by Shade Eye NCC computer colorimeter in a dark environment under black and white background, and the translucency parameter (TP) was used to evaluate the translucency of zirconia.
RESULTS
Speed sintering may decrease the TP of ST and increase the TP of TT. As for the effect of low-temperature degradation on the translucency of zirconia, the TP of ST decreased with the extension of aging time, and no significant difference was found in rapid sintering ST. Although the TP of TT decreased, no statistical difference was observed.
CONCLUSIONS
Speed sintering may decrease the translucency of high-strength zirconia and increase the translucency of high-translucent zirconia. Low-temperature degradation had no effect on the translucency of high-translucent zirconia. Speed sintering can be recommended for high-translucent zirconia in terms of translucency.
Topics: Ceramics; Dental Materials; Materials Testing; Surface Properties; Zirconium
PubMed: 38475952
DOI: 10.7518/hxkq.2024.2023249 -
Hua Xi Kou Qiang Yi Xue Za Zhi = Huaxi... Jun 2017This study aims to compare the three commonly used translucency parameters in prosthodontics: transmittance (T), contrast ratio (CR), and translucency parameter (TP).
OBJECTIVE
This study aims to compare the three commonly used translucency parameters in prosthodontics: transmittance (T), contrast ratio (CR), and translucency parameter (TP).
METHODS
Six platelet specimens were composed of Vita enamel and dental porcelain. The initial thickness was 1.2 mm. The specimens were gradually ground to 1.0, 0.8, 0.6, 0.4, and 0.2 mm. T, color parameters, and reflection were measured by a spectrocolorimeter for each corresponding thickness. T, CR and TP were calculated and compared.
RESULTS
TP increased, whereas CR decreased, with decreasing thickness. Moreover, T increased with decreasing thickness, and exponential relationships were found. Two-way ANOVA showed statistical significance between T and thickness, except between T and the 1.2 mm and 1.0 mm enamel porcelain groups. No difference was found among the coefficient variations (CV) of T, CR and TP. Curve fitting indicated the existence of exponential relationships between T and CR and between T and TP. The values for goodness of fit with statistical significance were 0.951 and 0.939, respectively (P<0.05).
CONCLUSIONS
Under the experimental conditions, T, TP and CR achieved the same CV. T and TP, as well as T and CR, were found with exponential relationships. The value of CR and TP could not represent the translucency precisely, especially when comparing the changing ratios.
Topics: Color; Dental Enamel; Dental Porcelain; Prosthodontics
PubMed: 28675013
DOI: 10.7518/hxkq.2017.03.010 -
Insects Feb 2023The light reflected by the dorsal side of butterfly wings often functions as a signal for, e.g., mate choice, thermoregulation, and/or predator deterrence, while the...
The light reflected by the dorsal side of butterfly wings often functions as a signal for, e.g., mate choice, thermoregulation, and/or predator deterrence, while the ventral wing reflections are generally used for crypsis and camouflage. Here, we propose that transmitted light can also have an important role in visual signaling because, in many butterfly species, the dorsal and ventral wing sides are similarly patterned and locally more or less translucent. Extreme examples are the Japanese yellow swallowtail ( Linnaeus, 1758) and the Yellow glassy tiger ( Fabricius, 1787). Their wings exhibit a similar color pattern in reflected and transmitted light, which allows enhanced visual signaling, especially in flight. Contrasting cases in which the coloration and patterning of dorsal and ventral wings strongly differ are the papilionid Linnaeus, 1758, and the pierid Fabricius, 1775. The wings observed in reflected or transmitted light then show very different color patterns. Wing translucence thus will strongly affect a butterfly's visual signal.
PubMed: 36975919
DOI: 10.3390/insects14030234 -
Medicina (Kaunas, Lithuania) Dec 2023Zirconia-reinforced lithium silicate (ZLS) ceramic is a new innovative dental material with unique a chemical composition that is designed to combine harmoniously with... (Review)
Review
Zirconia-reinforced lithium silicate (ZLS) ceramic is a new innovative dental material with unique a chemical composition that is designed to combine harmoniously with the appropriate optical properties of lithium disilicate and the enhanced mechanical strength of zirconia. A thorough understanding of ZLS materials is essential for both clinicians and dental technicians. At present, the mechanical behavior and optical properties of the ZLS ceramic system have not been extensively researched, and there is still a lack of consensus regarding the fabrication process and clinical behavior of ZLS all-ceramic restorations. The aim of the present study was to present a selection of comprehensive information concerning zirconia-reinforced lithium silicate ceramics and their optical and mechanical properties, as well as to assess data regarding cementation procedures and clinical outcomes for ZLS all-ceramic restorations. Three electronic databases (PubMed, Web of Science, and the Cochrane Library) were used for the research by two independent reviewers. The search was limited to articles published in the English language, as well as clinical and in vitro studies of color and studies on mechanical behavior and the cementation procedures of ZLS restorations. The exclusion criteria comprised abstracts, questionnaire-based studies, case reports, literature reviews, and studies that were not available in English. Zirconia-reinforced lithium-silicate-based ceramic presents a unique and complex microstructure that increases mechanical resistance but decreases aesthetic appearance, especially its translucency, due to tetragonal zirconia content. A material's thickness, the color of the underlying tooth structure, and the resin cement shade are important factors that influence the final shade and aesthetic appearance of ZLS restorations. Mechanical properties, which are defined by the fracture toughness, flexural strength, elastic modulus, and hardness of ZLS ceramic are higher compared to feldspathic, lithium disilicate, and hybrid ceramics, as well as resin nanoceramics; however, they are lower than translucent or high-translucency zirconia. Acid etching, sandblasting, and laser etching represent the most used methods to prepare the ZLS restoration surfaces for proper bonding procedures.
Topics: Humans; Ceramics; Dentistry; Lithium; Materials Testing; Silicates; Surface Properties
PubMed: 38138238
DOI: 10.3390/medicina59122135 -
Foods (Basel, Switzerland) Jun 2023Translucent egg consumption is low due to consumer acceptance and quality concerns, which is a problem that egg producers need to address. This study was performed to...
Translucent egg consumption is low due to consumer acceptance and quality concerns, which is a problem that egg producers need to address. This study was performed to evaluate the reasons for the high occurrence of egg translucency in summer, as well as whether the addition of mono-dicalcium phosphate (MDCP) to the diet can relieve eggshell translucency and whether eggshell translucency is associated with the risk of bacterial invasion. A total of 72 laying hens that were 36 weeks old were randomly divided into control (CON) and MDCP groups and fed in the same environment. Results showed that the number of translucent eggs increases in July and August as the temperature and humidity increase. Compared with the CON group, in July, August, and October, the translucent egg grade (TEG) of the MDCP group was lower than that of the CON group ( < 0.05). TEG was correlated with mastoid space height (MSH), width (MSW), and area (MSA) (correlation coefficients 0.63, 0.59, and 0.68, respectively, ≤ 0.05). There was no significant difference in the invasion rate of between translucent and non-translucent egg groups (47.2% vs. 39.33%), and translucent area and non-translucent area (13.49% vs. 15.08%). In conclusion, our results show that dietary MDCP may alleviate eggshell translucency and that eggshell translucency would not increase the probability of cross-shell penetration rate.
PubMed: 37444276
DOI: 10.3390/foods12132538 -
Dentistry Journal Sep 2019The purpose of this paper was to update the knowledge concerning the wear, translucency, as well as clinical performance of monolithic zirconia ceramics, aiming at... (Review)
Review
The purpose of this paper was to update the knowledge concerning the wear, translucency, as well as clinical performance of monolithic zirconia ceramics, aiming at highlighting their advantages and weaknesses through data presented in recent literature. New ultra-translucent and multicolor monolithic zirconia ceramics present considerably improved aesthetics and translucency, which, according to the literature reviewed, is similar to those of the more translucent lithium disilicate ceramics. A profound advantage is their high strength at thin geometries preserving their mechanical integrity. Based on the reviewed articles, monolithic zirconia ceramics cause minimal wear of antagonists, especially if appropriately polished, although no evidence still exists regarding the ultra-translucent compositions. Concerning the survival of monolithic zirconia restorations, the present review demonstrates the findings of the existing short-term studies, which reveal promising results after evaluating their performance for up to 5 or 7 years. Although a significant increase in translucency has been achieved, new translucent monolithic zirconia ceramics have to be further evaluated both in vitro and in vivo for their long-term potential to preserve their outstanding properties. Due to limited studies evaluating the wear properties of ultra-translucent material, no sound conclusions can be made, whereas well-designed clinical studies are urgently needed to enlighten issues of prognosis and long-term survival.
PubMed: 31480688
DOI: 10.3390/dj7030090