Color and translucency of zirconia ceramics, human dentine and bovine dentine (original) (raw)
Egyptian dental journal, 2021
Aim: to evaluate the influence of immersion time in coffee staining solution on the color coordinates of two Zirconia-containing indirect aesthetic materials. Material and methods: 20 Discs were used in the current study; samples have been divided into two groups in accordance with the material used (monolithic Zirconia restoration group [Zirconia] and indirect Zirconia silicate filled composite restoration group [Ceramage]. The samples were prepared and then immersed in coffee [staining solution]. Spectrophotometric analysis was made immediately after manufacturing of discs at (T0), at 7days (T1), 14 days (T2) and at 21days. Results: At T0-T1, T1-T2, T0-T2 and T0-T3, the mean ΔE of Zirconia showed statistically significantly lower value than Ceramage. At T2-T3; no statistically significant difference between mean ΔE of the two ceramic types was found (P-value = 0.155, Effect size = 0.235). Regardless of time; Zirconia showed a statistically significant lower mean ΔE than Ceramage ...
Research Square (Research Square), 2021
Translucent zirconia represents a favourite material for monolithic ceramic dental restorations. However, materials approaches employed so far to improve the translucency of zirconia ceramics are accompanied by a significant decline in strength. Thus, we aimed to develop dental 3Y-TZP ceramics that can provide excellent strength and, simultaneously, enhanced translucency. In this investigation, machinable tetragonal zirconia ceramics based on fine mesostructured zirconia particles stabilized with 3 mol% of yttria and prepared by the gelcasting processing method were developed. Properties of sintered samples were characterised, namely: shrinkage, density, structure, surface roughness, hardness, biaxial strength, and total forward transmittance. Zirconia ceramics with an average biaxial strength of 1184 MPa and a total forward transmittance of 46.7% for a 0.5 mm thick sample at a wavelength of 600 nm were obtained. These ceramics exhibited homogeneous structure with grains sizes up to 620 nm and purely tetragonal phase composition. The developed ceramics provided a favourable combination of high translucency comparable even with the mixed cubic/tetragonal structure of a common 4Y-TZP, and very high strength that is achievable only in the pure tetragonal 3Y-TZP.
Zirconia and its novel compositions: What do clinicians need to know?
Quintessence international, 2019
For several years, there has been a clear trend in the dental market towards monolithic tooth-colored restorations. In this context, further developments, particularly in the field of zirconia ceramics, have led to considerable improvement in the materials' optical properties. Modern zirconia materials can be divided into several cohorts, differing from each other with respect to their optical and mechanical properties. The knowledge about indications and limitations of each zirconia cohort is essential for a correct clinical application. Clinical long-term experience for the zirconia of the newest generations is still scarce and only in-vitro data are available. Despite all advancements, clinical long-term success remains closely linked to the specific indications, preparation, material selection, knowledge, and experience of the dental practitioner and dental technician, as well as an adequate luting mode and occlusal concept. Due to the high innovation rate within materials a...
World Academy of Science, Engineering and Technology, International Journal of Medical, Health, Biomedical, Bioengineering and Pharmaceutical Engineering, 2017
The ceramic yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) has been used as a dental biomaterial for several decades. The strength and toughness of this material can be accounted for by its toughening mechanisms, which include transformation toughening, crack deflection, zone shielding, contact shielding, and crack bridging. Prevention of crack propagation is of critical importance in high-fatigue situations, such as those encountered in mastication and para-function. However, the poor translucence of Y-TZP in polycrystalline form is such that it may not meet the aesthetic requirements due to its white/grey appearance. To improve the optical properties of Y-TZP, more detailed study of the optical properties is required; in particular, precise evaluation of the refractive index, absorption coefficient, and scattering coefficient are necessary. The measurement of the optical parameters has been based on the assumption that light scattered from biological media is isotropically distributed over all angles. In fact, the optical behavior of real biological materials depends on the angular scattering of light due to the anisotropic nature of the materials. The purpose of the present work is to evaluate the optical properties (including color, opacity/translucence, scattering, and fluorescence) of zirconia dental ceramics and their control through modification of the chemical composition, phase composition, and surface microstructure.
The Journal of Prosthetic Dentistry, 2019
Using a ceramic instead of a metal core allows more light transmission within a crown and therefore creates restorations with improved color and translucency. 1 Layering a strong ceramic core, such as yttriastabilized tetragonal zirconia (Y-TZP) with a highly esthetic veneering porcelain, can provide a restoration with excellent esthetics. 2 The excellent mechanical properties of Y-TZP is derived from the transformation toughening mechanism. 3 Matching the color of ceramic restorations to natural teeth is influenced by the surface texture, translucency, fluorescence, opalescence, porcelain brand and batch, number of porcelain firings, porcelain thickness, and condensation technique. 4,5 A ceramic restoration will look more translucent if most of the light is diffusely transmitted and only part of it is scattered. 6-8 Kelly et al 9 reported the core translucency as a pivotal factor in the esthetic outcome and a crucial consideration in material selection. Increasing the crystalline content of the core material improves strength but generally raises the opacity. 3,10 The translucency parameter is measured from the color difference of specimens on black and white backgrounds. 5,7 Some studies have reported that firing causes clinically significant color changes as the pigment breakdown occurs at porcelain firing temperatures. 11,12 However, other investigations have reported that porcelain color remains stable despite repeated firings. 2-4
Development of Translucent Zirconia for Dental Crown Applications
Asian Journal of Scientific Research, 2015
Zirconia-based dental ceramic is widely used for crown restoration, because of its superior mechanical properties and favorable biocompatibility. However, yttria-stabilized tetragonal zirconia (3YSZ), which is used in most dental crown restorations, has low translucency. This characteristic is unfavorable and results in low aesthetic quality of dental restoration. In this study, translucent 3YSZ dental ceramics were fabricated using nano-sized powder (20 nm) and high-temperature sintering (1500°C). The green bodies were slip casted and consolidated with cold iso-static pressing to create compact bodies. During the slip casting process different amounts of dispersing agent Polyethyleneimine (PEI) (0.2, 0.4, 0.6 and 0.8 wt%), were used to prevent agglomerates and create homogeneous suspensions. A minute amount (0, 0.1, 0.2, 0.3 and 0.4 wt%) of alumina was added into the suspension as sintering aid. The translucency or light transmittance of 3YSZ specimens was measured by an ultraviolet-visible spectrometer. Results showed that the 3YSZ specimen with 0.4 wt% alumina and 0.4 wt% PEI exhibited the highest light transmittance. The specimen also had larger grain size, because of excessive grain growth. The Vickers hardness of the specimens was insignificantly affected by the amount of alumina and PEI addition.
Zirconia Use in Dentistry - Manufacturing and Properties
Current Health Sciences Journal, 2019
Several types of metal-free ceramics have been developed to meet the patients demand for natural looking appearance restorations. Owing to their biocompatibility and good mechanical properties zirconia has been successfully used in recent years as a dental biomaterial. Due to its high opacity zirconia cores are generally covered with ceramic veneers that provide a more natural appearance but have frequent incidence of chipping. As an alternative to veneered zirconia full-contour zirconia restorations become more widely used nowadays. The paper reviews the current knowledge and scientific data of the zirconia use in dentistry in order to compare the zirconia based dental restorations with the metal-ceramic ones and also the two types of dental restoration based on zirconia, veneered or monolithic zirconia.
Effect of Different Coloring Procedures on the Aging Behavior of Dental Monolithic Zirconia
Journal of Spectroscopy
Objective. This study aimed to investigate the effect of different coloring procedures on the aging behavior of dental monolithic zirconia. Methods. Two types of translucent zirconia (SuperfectZir HTS, Aidite; Katana HT, Kuraray) were tested. Bar-shaped specimens with dimensions of 22 × 4 × 2 mm were prepared from uncolored and precolored blocks. Before being sintered, specimens made from uncolored blocks were colored by dipping them into a coloring liquid, whereas the precolored specimens were not treated. The specimens were then divided into 4 subgroups (n = 13) according to the aging conditions (no aging, 134°C/0.2 MPa for 5 h, 134°C/0.2 MPa for 10 h, and 134°C/0.2 MPa for 20 h). The flexural strength of the specimens was tested with the 4-point flexure. The crystalline phase composition of the specimens was analyzed by XRD. The subsurface microstructure of the fractured specimens was examined by using a SEM. The data were statistically analyzed using 3-way ANOVA and Tukey’s test...
Zirconia a Modern Ceramic Material in Dentistry - a Systematic Review
Among the dental ceramics, zirconia has emerged as a resourceful and promising material because of its biological, mechanical and optical properties, which has certainly accelerated its routine use in CAD/CAM technology for different types of prosthetic treatment. The zirconia systems currently available for use in dentistry include ceramics with a 90% or higher content zirconium dioxide, which is the yttrium, stabilized tetragonal Zirconia (Y-TZP) and glass infiltrated ceramics with 35% partially stabilized zirconia. Zirconia based restorations are quite versatile and can be used for crowns, bridges, implant abutments and fixtures and as post materials. This article reviews the unique property of zirconia and its wide application in dentistry, with more emphasis on prosthetic uses. Keywords: Zirconia, Esthetics, Restorations, Mechanical properties.
Open Access Macedonian Journal of Medical Sciences
BACKGROUND: The color of all ceramic restorations has a significant effect on the final appearance of the restoration. AIM: This study aimed to evaluate the effect of different shading techniques on the color stability of monolithic zirconia crowns cemented on the upper anterior teeth. METHODS: In this study, there were nine patients. Each patient has undergone a reduction for the upper six anterior teeth. Fifty-four zirconia jacket crowns were constructed using CAD/CAM technique. According to the shading technique, the crowns were categorized into two groups (pre-shaded and liquid shaded), where the upper right reduced teeth received pre-shaded zirconia crowns while the upper left reduced teeth received liquid-shaded zirconia crowns according to the selected shade. The color was assessed using easy shade after cementation and 1 year follow-up period. Data were collected, tabulated, and statistically analyzed. RESULTS: Color change (ΔE) of the cemented pre-shaded zirconia crowns on ...