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PubMed2007

Combined effect of staining substances on the discoloration of esthetic Class V dental restorative materials.

The purpose of this study was to determine the combined effect of an organic substance (mucin as a substitute for salivary organic substances), chlorhexidine, and an iron compound/tea solution on the changes in the color of esthetic Class V dental restorative materials. Color of a glass ionomer, resin-modified glass ionomer, compomer and flowable resin composite of A2 shade, respectively, was determined according to the CIELAB color scale relative to the standard illuminant D65. Color was measured at baseline, and after sequential immersion in the following substances: Step-1, mucin in PBS (MCP) for 48 h; Step-2, chlorhexidine (CHX) for 24 h; Step-3, iron compound (IRN) or tea solution (TEA) up to 7 days; and Step-4, ultrasonic cleaning for 1 h. Color change (DeltaE(ab )*) was calculated by the equation: DeltaE(ab)* = [(DeltaL*)(2) + (Deltaa*)(2) + (Deltab*)(2)](1/2), of which DeltaL(*) indicates changes in value, Deltaa(*) indicates changes in red-green parameter and Deltab(*) indicates changes in yellow-blue parameter. DeltaE(ab)* values after immersion in MCP and CHX were compared, and DeltaE(ab)* values after immersion in IRN or TEA, and subsequent ultrasonic cleaning were compared with respect to the restorative material and immersion substance. DeltaE(ab)* and changes in the color parameters (DeltaL(*), DeltaC(ab)* and DeltaH(ab)*) were analyzed by repeated measures, analysis of variance and a post-hoc test at the 0.05 level of significance. Color changes after immersion in MCP were acceptable (DeltaE(ab)* < 3.3), and those after immersion in CHX were generally acceptable. The range of DeltaE(ab)* values after immersion in IRN was 3.1-19.6, and that after ultrasonic cleaning was 2.4-9.6. The range of DeltaE(ab)* values after immersion in TEA was 10.7-21.1, and that after ultrasonic cleaning was 11.9-14.5. Color changes of four Class V restorative materials after combined treatment with mucin, chlorhexidine and an iron compound/tea solution were not acceptable. Colors did not recover to their original values after ultrasonic cleaning. Modifications on the surface of a restoration should be considered to reduce stain accumulation.

Acrylic Resins↗
PubMed2006

Changes in optical properties of enamel porcelain after repeated external staining.

STATEMENT OF PROBLEM: After staining a porcelain restoration, increasing the lightness (value) and decreasing the chroma of a restoration is not practically easy to accomplish. PURPOSE: The purpose of this study was to determine the color change of enamel porcelain after repeated external staining procedures over the enamel porcelain surface. Changes in translucency and differences in surface roughness were also measured. MATERIAL AND METHODS: Enamel porcelain (VITA OMEGA 900 Metal Ceramics) disks (1 x 12 mm) of 1 shade (EN2) were prepared, and 1 of 4 types of external stains (VITA Akzent stains) was applied over the specimens and fired. Firing was repeated 3 times after application of the same stains. Color of the specimens before and after stainings was measured with a reflection spectrophotometer. Two-factor repeated-measures analysis of variance with the fixed factors of the stain type and number of staining cycles for the changes in CIE L(*), CIE a(*), CIE b(*), color (DeltaE(*)(ab)), and chroma (DeltaC(*)(ab)) after repeated staining was performed (alpha=.05). Chroma change was calculated as DeltaC(*)(a)=(Deltaa *(2) +Deltab *(2))(1/2). Changes in translucency (translucency parameter and masking effect) and difference in surface roughness (Ra) after the third staining cycle were also determined. RESULTS: Color change after the first staining cycle was perceptible (DeltaE(*)(ab) >2) for 2 of 4 types of stains and was perceptible for all 4 types of stains investigated after the third staining cycle (DeltaE(*)(ab) = 2.36-11.04). Lightness generally increased, and chroma also increased after staining but varied by the type of stains and number of staining cycles. Translucency generally decreased after repeated staining. Surface roughness varied by the type of stain (P < .001). CONCLUSION: Color difference and lightness increased significantly after repeated staining cycles, but chroma change was small after repeated staining cycles. Therefore, repeated staining may be a method to increase the lightness of enamel porcelain.

Color↗
PubMedDate not supplied

Color accuracy of resin cements and try-in pastes.

The color accuracy of resin composite cements and their corresponding try-in pastes was assessed. Three shades of three brands were compared using the cements alone and in contact with a standard porcelain disk. There were significant differences in color between resin cements and their corresponding try-in pastes. The addition of a 1-mm-thick porcelain disk greatly reduced the apparent color differences. The color of resin cements changed over time, but not significantly. Baseline measurements of resin cement colors were compared and measurements made after 24 hours of storage. Color changes were statistically significant but not perceptible, and all samples became slightly darker with age.

Analysis of Variance↗
PubMed1994

Color management.

One of the most rewarding experiences for a cosmetic dentist is placing a restoration that harmoniously blends with the surrounding dentition. To obtain this result, one must master the science and art of dental color. Although there have been substantial advances in color teaching during the past few decades, there are still major shortcomings in the development of predictable shades of restorative materials. With the recent influx of new dental materials, and the demand of patients to improve their smiles, the dental profession is finding new solutions to help improve the management of color within the dental profession. This review highlights some important issues in color management from both the clinical and technological points of view.

Crowns↗
PubMed2004

The effect of surface finishing and storage solutions on the color stability of resin-based composites.

BACKGROUND: The authors tested the hypothesis that surface-finishing treatments and the type of storage solutions significantly affected the staining of resin-based composites, or RBCs, and unfilled resins, or URs. METHODS: Fifty-four RBC and 54 UR disks were polymerized through a polyester film strip (Mylar, DuPont, Wilmington, Del.) and polished in one of three groups: 1-micrometer aluminum oxide, 15-microm diamond plate and no treatment (polyester film). All specimens were immersed in water for two days and then in coffee, cola or red wine for seven more days at 37 C. The authors recorded tristimulus color measurements before the immersions; after one and two days in water; and after one, two, three and seven days in the storage solutions. RESULTS: Most of the color changes occurred between day 2 in water and day 7 in the staining solution. Analysis of variance showed that the finishing treatment and storage solution significantly influenced the overall color change (deltaE), and interactions occurred between the finishing treatment and the storage solution (P < .0001) for both materials. RBC specimens generally exhibited greater color changes than did UR specimens. The polyester film finishing exhibited the greatest amount of color change, while the diamond finishing exhibited the least amount of color change. Immersion in wine caused the greatest color change for both materials; cola and coffee resulted in the smallest color change for RBC and UR specimens, respectively. CONCLUSIONS: Finishing treatments and storage solutions significantly affect the surface staining of RBC materials. Polyester film finishing and red wine produced the greatest color change after seven days for RBC specimens. CLINICAL IMPLICATIONS: Clinicians should remove the polyester film-finished surface and advise patients that drinking wine could intensify surface staining on RBC restorations.

Aluminum Oxide↗
PubMed2005

Effects of plaque disclosing agents on esthetic restorative materials used in pediatric dentistry.

The aim of study was to evaluate the color stability of tooth-colored restorative materials usually used in pediatric dentistry after the application of two plaque disclosing agents. Twenty specimens of each material: a resin-modified glass ionomer, a composite resin and an ion-releasing composite resin, were prepared. Baseline color evaluation was performed, samples were exposed to the plaque disclosing agents: a basic fuchsin solution and a fluorescent dye, and new color evaluations were made. The resin-modified glass ionomer stained with basic fuchsin presented the greatest color change in the present study, and the fluorescent dye did not show statistically significant changes among the restorative materials. In conclusion, basic fuchsin dyes should be carefully used in children with a great number of tooth-colored restorations.

Child↗
PubMed2004

Composite tints: mixing composite materials to alter color and techniques to simulate hypocalcification and craze lines.

The purpose of this article is to teach advanced composite techniques based on sound material science and advanced artistic principles. The effects of oxygen inhibition, shrinkage, wear, filler content, and composite chemistry are reviewed. Color blending using composite translucency to show through underlying and surrounding tooth structure achieves improved color matching and color transition from tooth structure to a composite restoration. Mixing color tints modifies composite color, and applying composite tints produces effects such as hypocalcifications and craze lines.

Color↗
PubMed2005

Shading of ceramic crowns using digital tooth shade matching devices.

In the 1990s, there was great optimism due to the development of devices for measuring tooth shade. The frequently not so simple, visual determination of the shade of a tooth was to be done with the aid of a device which recognizes the shade and describes it accurately by reference to a color chart. However, the skepticism towards such devices was also great. It is known that the color effect frequently differs strongly when comparing a tooth from the shade guide with a metal ceramic crown, despite identical shade designation. Anyone who considers visual shade determination to be inadequate and places his hopes in digital shade matching devices will be disappointed. It is the shade-generating structures of the metal ceramic and frequently of the veneer layers that turn out to be too thin which, despite correct shade selection, cause a different color perception. Such problems have been reduced decisively with the development of fracture-proof hard porcelain caps (Vita In-Ceram) with optical characteristics similar to teeth. In addition, the Vita System 3D-Master tooth shade system developed in 1998 by Vita in cooperation with Dr. Hall from Australia, leads the practitioner to a better understanding of the primary tooth shade characteristics of "brightness (value)", "color intensity (chroma)" and "color (wave length of the visible light, hue)". These two innovations allow a more accurate estimate of the basic shade of a natural tooth (reference tooth) and the imitation in the laboratory of its natural, shade-generating structures. If digital shade measurement supplements the visual shade estimate, then a further improvement can be expected--especially in the recognition of the basic shade. Qualitative descriptions of subjective shade measurement of a natural tooth and of its imitation in the dental laboratory by ceramics can be found frequently in professional journals and publications. With digital tooth shade matching devices, which apart from the color code of the color chart also reproduce exact, colorimetric values, such work processes can be recorded quantitatively and objectively. Reports about this type of controlled shade determination and generation are found rarely in the literature, which is surprising in view of the large number of tooth shade matching devices and dental ceramic systems available. In the present paper, the influence of the individual ceramic layers on color perception is measured and described under standardized conditions. The creation of the basic shade as it results from the composition of the various ceramic layers is traced with a spectrophotometer. The Vita In-Ceram Alumina infiltration ceramic and the VitaVM7 veneer ceramic were selected as the ceramic system. MHT-SpectroShade and Vita Easyshade were used as shade matching devices.

Aluminum Oxide↗
PubMedDate not supplied

Color stability of denture base polymers.

One light-polymerized, three heat-polymerized, and three autopolymerized denture base polymers were exposed to coffee, tea, water at 50 degrees C +/- 1 degree C, as well as artificial sunlight and water, and evaluated for color stability. The color characteristics were determined using a computer-controlled spectrophotometer. Water sorption and solubility were assessed, and the materials were also chemically characterized. Coffee and tea stained the denture base materials superficially. Brushing with toothpaste and moderate grinding reduced discoloration to an acceptable level. All materials were relatively color stable when immersed in water at 50 degrees C +/- 1 degree C. The materials behaved differently when exposed to artificial sunlight and water.

Chromatography, Gas↗
PubMed1996

Light and color in anterior composite restorations.

As defined by physics, color is light. With this premise, this article highlights the importance of the interaction between light and the hard tissues of the tooth as compared to the interaction between light and composite restorative materials. Based on the philosophy of color interpretation and its subsequent practical application in the development of a fluorescent and opalescent microhybrid composite system, the protocol outlined allows the clinician to achieve restorations with a light/composite interaction that closely resembles that of light/natural dentition. The learning objective of this article is to present specific diagnostic techniques to establish predictable identification and reproduction of the natural anatomy and nuance color characteristics exhibited by natural dentition with composite resin. A detailed evaluation of hue, chroma, opalescence, and fluorescence are presented in order to simplify the composite stratification technique.

Color↗
PubMed1997

Aesthetic all-ceramic restorations: the internal live stain technique.

The utilization of porcelain as a restorative material began a new era in aesthetic dentistry. By today's standards, the early porcelains were rather primitive and of low value. However, the potential of all-ceramic material for aesthetic dentistry was recognized, and various modifications and enhancements followed to render the material applicable for dental restorations. The learning objective of this article is to present the history of development, the principles, and the laboratory fabrication of ceramic restorations utilizing the Internal Live Stain Technique. The technique uses stains with all-ceramic material to achieve the optimal simulation of natural dentition. While replicating the optical properties inherent in the natural dentition, the application of the stain improves the physical characteristics of the all-ceramic material. The general principles of the first and second applications are disclosed, followed by presentation of two clinical cases--all-ceramic crown and laminate veneer restorations in the maxillary anterior segment.

Adult↗
PubMed2004

Influence of illuminating and viewing aperture size on the color of dental resin composites.

OBJECTIVES: The objective was to evaluate the difference in the color of dental resin composites by the illuminating and viewing aperture sizes. The influences of the color measuring geometry, standard illumination and surface roughness on the color were also determined. METHODS: Color of five brands of resin composites of A2 shade was measured after-polymerization and after-polishing. Color was measured according to the CIE L(*)a(*)b(*) color scale with the SCE and SCI geometry under the CIE standard illumination of A and D65. The illuminating/viewing aperture sizes were 11 mm/8 mm (8 mm) and 3 mm/3 mm (3 mm). RESULTS: Regardless of the measuring geometry, CIE L(*), a(*) and b(*) values measured at 3 mm were lower than those at 8 mm. Changes in L(*), a(*) and b(*) values by the difference in the aperture size were 17.22-21.32, 3.43-6.64 and 13.82-16.81, respectively, and the color difference (DeltaE(*)) was 16.23-27.87 with the SCE geometry. Regardless of the aperture size, DeltaE(*) values caused by polishing measured with the SCE were significantly higher than those with the SCI. SIGNIFICANCE: Aperture size, measuring geometry and surface conditions of specimen should be considered when comparing the result of color measurement.

Colorimetry↗
PubMedDate not supplied

Kubelka-Munk reflectance theory applied to porcelain veneer systems using a colorimeter.

The purpose of this study was to demonstrate the ability of Kubelka-Munk reflectance theory to predict color parameters of veneer porcelain on various backings using colorimetric measurements. Tristimulus absorption and scattering coefficients were used to predict the respective tristimulus reflectance values of A1, D3, and translucent porcelain samples after they had been bonded to light and dark substrates using universal, opaque, and untinted shades of bonding resin. Observed and predicted reflectance values exhibited high correlation (r2 > or = 0.93 for each porcelain shade). Kubelka-Munk theory offers an accurate prediction for the resultant colorimetric reflectance parameters of veneer porcelain bonded to variously colored backings.

Absorption↗
PubMed2000

Effects of fluoride varnish on color of esthetic restorative material.

PURPOSE: This study determined the color stability of a compomer, hybrid ionomer, and composite after staining with three fluoride varnishes. MATERIALS AND METHODS: Five disks (10 mm in diameter, 2 mm thick) of each material were prepared in a mold and incubated at 100% relative humidity at 37 degrees C for 24 hours. Duraphat, Duraflor, FluorProtector, and water (control) were applied to the disks, which were subsequently brushed with a soft toothbrush and dentifrice. Color was measured at baseline, after staining, and after brushing using CIE L*a*b* (source C) against white background on a reflection spectrophotometer, and color change (delta E*) was calculated. Means (n = 5) and standard deviations were calculated and compared using a repeated-measures analysis of variance (ANOVA). Tukey-Kramer intervals (p = .05) were calculated to compare means. RESULTS: Varnishes Duraflor and Duraphat caused perceptible color changes (delta E* > 3.3) in compomer, hybrid ionomer, and composite after application; however, FluorProtector did not affect the color of the materials. After brushing, none of the materials exhibited perceptible values of delta E*, except the composite with Duraflor (delta E* = 5.4).

Analysis of Variance↗
PubMed2001

Color stability of glass-ionomers and polyacid-modified resin-based composites in various environmental solutions.

PURPOSE: To evaluate the degree of color stability of glass-ionomers (GIs) and polyacid modified resin-based composites (PMRBCs) in various environmental solutions. MATERIALS AND METHODS: Seven polyacid-based esthetic restorative materials were used: three chemical-cured GIs, one resin-modified GI and three polyacid-modified RBCs. A light-cured resin-based composite (RBC) (Z 100) was used as a control. Disk type specimens were prepared and were aged in four different solutions (deionized water, 0.1 mole acetic acid solution, 75% ethanol, and 10% hydrogen peroxide solution) for 1, 7, 14, 21, 28, and 56 days. The specimens were kept at 37 degrees C throughout the study. Color coefficients (CIE L*a*b*) were measured by a reflection spectrophotometer with SCE mode, and the surface of specimens was examined by a stereo zoom microscope. RESULTS: In deionized water, all specimens showed an acceptable color stability. All of the GIs and PMRBCs showed significant color change in 0.1 mole acetic acid solution. The light-cured resin-modified GI showed a significant color change in 75% ethanol solutions. 10% hydrogen peroxide solution resulted in degradation and a high degree of color change for chemical-cured GIs. The light-cured resin-modified GI and PMRBCs showed high color change in 10% hydrogen peroxide solution. The light-cured RBC (Control), showed excellent color stability in all experimental solutions.

Acetic Acid↗