The effect of repeated firings on the color change of dental ceramics using different glazing methods (original) (raw)
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The effect of repeated firings on the color change and surface roughness of dental ceramics
The Journal of Advanced Prosthodontics, 2014
PURPOSE. The color of the ceramic restorations is affected by various factors such as brand, thickness of the layered the ceramic, condensation techniques, smoothness of surface, number of firings, firing temperature and thickness of dentin. The aim of this study was to evaluate the color change and surface roughness in dental porcelain with different thicknesses during repeated firings. MATERIALS AND METHODS. Disc-shaped (N=21) metal-ceramic samples (IPS Classic; Ivoclar Vivadent; Shaar, Liechtenstein) with different thickness were exposed to repeated firings. Color measurement of the samples was made using a colorimeter and profilometer was used to determine surface roughness. ANOVA and Tukey tests with repeated measurements were used for statistical analysis. RESULTS. The total thickness of the ceramics which is less than 2 mm significantly have detrimental effect on the surface properties and color of porcelains during firings (P<.05). CONCLUSION. Repeated firings have effects on the color change and surface roughness of the dental ceramics and should be avoided.
The Journal of Prosthetic Dentistry, 2007
Statement of problem. Although all-ceramic restorations are widely used, there is a lack of information on how color is affected by fabrication procedures. Color matching problems may be encountered in a definitive restoration despite careful shade selection. Purpose. The aim of this study was to evaluate the effect of dentin ceramic thickness and repeated firings on the color of glass-infiltrated aluminum-oxide (In-Ceram) and leucite-reinforced (IPS Empress) all-ceramic systems using a colorimeter. Material and methods. Twenty-one disc-shaped specimens, 10 mm in diameter with a 0.6-mm core thickness and 0.5-, 1-, or 1.5-mm dentin ceramic thickness, were made from each of 2 ceramic systems (n=7). Repeated firings were performed for each group, and the color differences were compared with the color after the initial firing. Color differences among ceramic specimens were measured using a colorimeter (XL-20 Colorimeter), and data were expressed in Commission Internationale d'Eclairage (CIE) LAB system coordinates. Repeated-measures analysis of variance was used to analyze the data (number of firings, ceramic brand, and ceramic thickness) for significant differences. The Tukey honestly significant difference test and paired 2-tailed tests were used to perform multiple comparisons (a=.05). Results. The L*a*b* values of ceramic systems were affected by the number of firings (3, 5, or 7) (P,.01) and ceramic brand (In-ceram or IPS Empress) (P,.01). L* and a* values were affected by ceramic thickness (0.5, 1, or 1.5 mm) (P,.01); however, b* value was not affected by ceramic thickness (P=.075). Significant interactions were present in L*, a*, b* values between number of firings and ceramic brand (P,.01), and between ceramic brand and ceramic thickness (P,.05). Significant interactions were present between number of firings and ceramic thickness (P,.01) in L* and b* values but not in the a* value (P=.379). Conclusion. The analysis revealed that there were substantial changes in L*a*b* color data as the number of firings increased, which resulted in perceptual color changes in L*a*b* color parameters. (J Prosthet Dent 2007;97:25-31.) CLINICAL IMPLICATIONS The results of this in vitro study suggest that dentin ceramic thickness and repeated firings of the all-ceramic materials tested are important factors for the color of definitive restorations and should be considered during shade selection and fabrication.
Color stability and Microstructure Changes of Two Pressable Ceramics after Repeated Firing protocols
Egyptian Dental Journal, 2020
Statement of the problem: it is important that researchers gather more information regarding the effect of repeated firing on optical properties and microstructure of all ceramic restoration Purpose: The aim of this in vitro study was to investigate the effect of repeated firing on color stability and microstructure changes using X-ray diffraction, EDAX and SEM of two pressable ceramics. Methods: A total number of forty eight freshly extracted maxillary central incisors were collected. The selected teeth were cleaned and disinfected in 0.5% sodium hypochlorite solution, then stored in distilled water for maximum two weeks until the testing began. The roots of the selected teeth were serrated with a disc for retention. The teeth were mounted vertically into autopolymerizing acrylic resin material. Full coverage all-ceramic preparation was performed for all teeth. The prepared teeth were randomly divided into two equal test groups (n=24) according to the all-ceramic materials used for crown fabrication as follows: Group I: IPS e-max Press (LD): Twenty four prepared teeth were restored with pressable lithium di-silicate glass ceramics (IPS e.max press, Ivoclar, Vivadent AG, Schann, Lieshtenstein). Group II: Celtra Press (ZL): Twenty four prepared teeth were restored with pressable zirconia-reinforced lithium di-silicate glass ceramics (Celtra Press, Dentsply, Sirona.). Then samples were subjected to repeated firing cycles up to five firing cycles. Samples were divided into four equal subgroups (n= 6), according to the number of firing cycles performed for each sample. Subgroup (A) : Control samples, subgroup (B):1 st firing cycle ,subgroup (C): 3 rd firing cycle, Subgroup (D): 5 th firing cycle. All ceramic crowns fabrication was done according to manufacturer instructions for each material. For each crown the L *, a* and b* was measured using spectrophotometer (Vita Easy shade) by placing the probe tip on the central part of the labial surface of the crown, the colorimetric values of ΔL*, Δ a* and Δb* were measured from differences in the respective L*, a*and b* values. The total color difference ΔE* were measured at each firing cycles subgroups for each group of ceramic materials. Data were collected, tabulated and statistically analyzed. Microstructural analysis for the two tested all ceramic materials was examined by X-ray diffractometer, scanning electron microscopy, the elemental chemical composition as well as quantitative analysis was measured by energy dispersive X-ray spectroscopy (EDAX) .This analysis was done after the control firing and the 5 th firing cycle.
Journal of Esthetic and Restorative Dentistry, 2019
Objective: The color of all-ceramic restorations is one of the main criteria to achieve esthetical success. Many factors such as ceramic thickness, condensation techniques, firing temperature, and numbers can affect the final color of restoration. The purpose of this study was to investigate the color changes in alumina-based ceramic system according to ceramic shade and thickness during the multiple firings. Materials and Methods: Sixty disc-shaped specimens with two different veneering porcelain shades (A1 or A3), and with three different ceramic thicknesses (0.5, 1, or 1.5 mm), were fabricated from an alumina-based ceramic system. Multiple firings (3, 5, 7, or 9 firings) were performed, and color changes (ΔE 00) were determined using a spectrophotometer. Repeated-measures ANOVA were used to analyze the data. The Duncan test was used for multiple comparisons (α = .05). Results: The L*a*b* values of the specimens were affected by the number of firings (3, 5, 7, or 9), veneering ceramic shades (A1 or A3) and veneering ceramic thicknesses (0.5, 1, or 1.5 mm). Significant interactions were present between the number of firings, veneering ceramic shade, and veneering ceramic thickness for L* (p < .001), a* (p < .001), and b* (p < .001) values. Conclusions: No statistically significant color change was observed between 3rd and 9th firings. Clinical Significance: Veneering ceramic shade, veneering ceramic thickness, and number of firings should be carefully considered to obtain an acceptable color match of the definitive restorations.
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...
Color Variation Between Matched and Fabricated Shades of Different Ceramics
Journal of Prosthodontics, 2013
Purpose: The aim of this study was to evaluate and compare the total color difference ( E) between natural teeth and fabricated crowns from three ceramic systems with different thicknesses. Materials and Methods: The color of ninety maxillary central incisors was measured from the middle third of the labial surface with a Vita Easyshade spectrophotometer. All-ceramic crown preparations with different thicknesses (0.8, 1.2, 1.5 mm) were done on selected teeth (n = 30). Prepared teeth were randomly divided into three equal groups to fabricate ceramic crowns from three ceramic systems, Duceram LFC (DLFC), In-Ceram SPINELL (ICS), and IPS Empress (IPSE). Colors of cemented crowns were measured and compared with their corresponding measurements before preparations. Data were statistically analyzed using two-way ANOVA at 5% significance level. Results: A significant difference of E was detected between natural teeth and different thicknesses of crowns constructed from the all-ceramic materials investigated. Comparing the three materials at 0.8 mm thickness revealed that the lowest E was recorded for DLFC, which was significantly different from the other ceramic systems while IPSE showed the highest E. At higher thicknesses there was no difference between natural tooth shade and crowns constructed from different ceramic materials. Conclusions: Reinforcement of ceramics by alumina for In-Ceram and leucite for Empress decreases color production. Level of acceptance between the different ceramic materials and thicknesses varied. DLFC showed the highest color matching at all thicknesses followed by ICS and IPSE in descending order. In general, increasing the thickness of fabricated crowns enhances color match.