Color and translucency of zirconia ceramics, human dentine and bovine dentine (original) (raw)
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Color and translucency of zirconia infrastructures and porcelain-layered systems
The Journal of Prosthetic Dentistry, 2018
With technological advances and the increase in esthetic requirements, ceramic alternatives to metal substructures have been developed. Ceramic restorations have excellent esthetic properties, chemical stability, and biocompatibility. 1 However, ceramic dental restorations had been limited to the anterior region because of the brittle character of dental ceramics and its low resistance to fracture in bending. 2 The development of higher strength dental ceramic systems has been followed by their use in the posterior regions. Zirconia ceramics with good mechanical properties, biocompatibility, and resistance against tensile forces may now be used in the posterior regions and for longspan fixed partial dentures. Although satisfying esthetic results can be accomplished with ceramic systems, the use of a fracture-resistant core material is necessary to withstand clinical functional and parafunctional forces. Although initial color may be less important to the long-term clinical success of dental restorations, appearance plays an important role in the success of the restoration for the patient, and so color has become an The study was supported by Scientific Research Projects Coordination Unit of Cukurova University, project number DHF2012D9.
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 ...
Variations in the Shades of Contemporary Dental Ceramics: An In Vitro Analysis
Crystals
Background: To identify and compare the shade variations of various commonly used esthetic dental ceramics by calculating their total-color-difference (ΔE) and translucency parameter (TP) using a spectrophotometer. Methods: In total, 165 disc specimens from three shades (A1, B1, and C1) of five ceramic materials (N = 55/shade; n = 11/ceramic material group) were prepared (Metal-ceramic (MC), IPS e.max press (Emax-P), IPS e.max layer (Emax-L), Layered Zirconia (Zr-L) and Monolithic zirconia (Zr-M)). With a spectrophotometer, the L*a*b* values were obtained. Total color differences (ΔE = [(ΔL*)2 + (Δa*)2 + (Δb*)2]1/2) and translucency parameter (TP = [(L*B − L*W)2 + (a*B − a*W)2 + (b*B – b*W)2]1/2) were calculated. The statistical tests included ANOVA and Post hoc Tukey’s analysis (p < 0.05). Results: Significant differences (p = 0.000) were found between the groups for ΔE. Highest ΔE (A1) were found for Zr-L (80.18 ± 20) and lowest for Zr-M (62.97 ± 1.28). For B1, highest ΔE value...
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.
Color related to ceramic and zirconia restorations: A review
Dental Materials, 2011
The requirement to achieve natural looking restorations is one of the most challenging aspects of dentistry, and the shade matching of dental restorations with the natural dentition is a difficult task due to the complex optical characteristics of natural teeth. Dental porcelain is considered the reference material for prosthetic rehabilitation, but it is not easy to handle and aesthetic excellence is quite difficult to obtain. For these reasons, shade matching with dental porcelain is often considered to be more artistic than scientific. Shade matching is considered unpredictable due to several variables that may influence the final appearance of a restoration. In order to improve this situation, over the last decade new shade guides and instruments have been developed and the aesthetic aspects of dental porcelain have been further investigated. In this review some aspects of color selection and color reproduction have been examined. Color selection has advanced through the development of new shade guides and electronic shade taking devices, although visual assessment has still not been entirely replaced by electronic instruments. Color reproduction with dental porcelain has improved thanks to advances in the performance and knowledge of dental porcelain, but is still not easy to achieve. The difficulties of achieving good aesthetics with PFM restorations and the desire for metal free solutions have resulted in the increased use of zirconia. The unique optical properties of zirconia have introduced new opportunities for achieving superior aesthetics, however further research is required with this material.
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.
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
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...
Journal of Research in Medical and Dental Science, 2018
Statement of the Problem: Controversy exists regarding the effect of porcelain thickness on color of restoration. Purpose: This study sought to assess the effect of thickness of the veneering ceramic on color parameters of zirconia all-ceramic restorations. Materials and Method: This in vitro experimental study was conducted on 30 discs measuring 10mm in diameter and 0.5mm in thickness fabricated of A3 shade of ZIRCAD zirconia using computer-aided design/computer aided manufacturing (CAD/CAD) system. Discs were divided into three groups (n=10). Disc-shaped metal molds measuring 10mm in diameter and 1, 1.5 and 2mm in height were used to fabricate IPS e.max veneering ceramic in 1, 1.5 and 2mm thicknesses. After applying porcelain and firing, the color parameters (CIE L*a*b*) were measured using a spectrophotometer in three phases of zirconia core, dentin porcelain and glazing. Color difference (ΔE) was compared among the three groups. Data were analyzed using ANOVA and Tukey’s test. R...
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 ...