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PubMed2005

Translucency and characteristics of newly developed polymer-based dental tooth coating material.

The purpose of this study was to evaluate the translucency and color change of simulated heavily discolored teeth using polymer-based dental tooth coating materials and flowable resin composites. Five shades of coating material and two shades of flowable resin composite were used. Colorimetric values of the materials in different shades were determined using the L*a*b* system of the Commission Internationale de l'Eclairage (CIE). Colorimetric examination was performed on white, black, and shade guide (C4) backgrounds using specimens of various thickness (0.2, 0.3, 0.5, 1.0, and 2.0 mm). New coating material showed less translucent than flowable resin composites. Moreover the new material showed the potential to improve the appearance of heavily discolored teeth when being applied as a thin first layer.

Analysis of Variance↗

PubMed1999

Direct reconstruction of the maxillary anterior dentition with composite resin: a case report.

Direct composite restorations continue to be a viable treatment alternative for numerous patients who desire anterior reconstructive procedures. In order to achieve optimal aesthetic and functional results, the clinician must possess a thorough understanding of composite resins and color and be able to simulate the optical properties of a natural tooth. This paper describes a sophisticated polychromatic color layering technique through the correct implementation of composite materials and freehand bonding techniques for the fabrication of ten direct resin veneer restorations in the maxilla.

Color↗

PubMed2004

[Color stability of porcelain-fused-to-titanium restorations after repeated firings].

OBJECTIVE: To study the effect of repeated firings on color of porcelain-fused-to-titanium restorations. METHODS: Twenty standard porcelain-fused-to-titanium specimens were made with Dentsply DETREY TiBond C3 and Dentaurum rematitan Til. Then they were fired 1, 2, 4, 7, and 10 times. Color measurement was done after each firing. RESULT: Most of the color parameters had no significant difference after firing except for a* and Hab. All the color difference among groups were smaller than 1.0 (deltaE < 1.0). CONCLUSION: Repeated firings will not affect the color stability of porcelain-fused-to-titanium restorations.

Color↗

PubMed1995

Color management of cosmetic restorations.

Ideally, a cosmetic restoration should be indistinguishable from the surrounding unrestored dentition. The cosmetic dentist faces the challenging task of creating the restoration using materials that do not possess the light-transmitting properties of natural tooth structures. A thorough knowledge of the physical and physiologic properties of light, color production and perception, and skill in the art of color matching can lead to rewarding success.

Dental Porcelain↗

PubMedDate not supplied

Changes in appearance of silicone elastomers for maxillofacial prostheses as a result of aging.

PURPOSE: The purpose of this study was to investigate the influence of certain defined variables on color and opacity of silicone elastomers for maxillofacial prostheses. MATERIALS AND METHODS: Three condensation-type and five addition-type silicone elastomers were tested for their changes in color and opacity as a result of aging. The specimens were aged under a xenon light source, dry or wet, and in darkness, also dry (control specimens) or wet. The aging times were 24, 96, 168, 336, 504, 840, 1176, and 1512 hours. The changes in appearance were measured with a spectrophotometer. RESULTS: The condensation-type polymers increased in opacity in an aqueous environment, while the addition-type polymers, as a group, showed the smallest color changes. Although the addition-type polymers generally had a higher filler content than the condensation types, they had a lower opacity. However, because of their higher viscosity, the condensation-type polymers offer better possibilities for intrinsic coloring of the prosthesis. CONCLUSION: Under the experimental conditions studied, significant differences between the silicone elastomers regarding color and opacity changes were demonstrated. However, for a proper choice of material in a given case, these factors have to be related to biologic and mechanical properties of the material.

Analysis of Variance↗

PubMed2005

Reproducibility of tooth color gradation using a computer color-matching technique applied to ceramic restorations.

STATEMENT OF PROBLEM: To reproduce tooth color precisely, an objective methodology based on color science is required. However, perception-based techniques are still the primary method for color matching in restorative dentistry. PURPOSE: This study evaluated the accuracy of reproduction of color gradation for ceramic restorations using a Computer Color Matching (CCM) technique employing a prototype program and spectrophotometric data measurements. MATERIALS AND METHODS: The colors of 10 target-shade tabs of the Vitapan 3D Master shade guide were measured at 4 regions of crowns from the cervical to the incisal area using a spectrophotometer. Tooth-shaped CCM ceramic specimens (30 specimens; 3 specimens for each of 10 target-shade tabs), the same size and shape as target-shade tabs, were fabricated according to the CCM prescriptions calculated using a prototype CCM program. The colors of CCM ceramic specimens and target-shade tabs were compared in 10 incremental areas from gingival to incisal (each measuring 1 mm high x 3 mm wide). The color differences, Delta E, Delta L* , Delta a* , and Delta b* , were calculated. The color difference Delta E values were analyzed by a repeated measures analysis of variance (P <.0001). Three prosthodontists evaluated CCM specimens by perception techniques. RESULTS: The mean color difference (Delta E) values were clinically acceptable (below 3.6) for incremental areas 3 through 10 and unacceptable for areas 1 and 2 (gingival area). Highly significant differences in the mean of Delta E values among target-shade tabs (P <.0001), areas (P <.0001), and target-shade tab-by-area interaction effects (P <.0001) were noted. However, perceptional evaluation indicated "Definitive match" or "Approximate match" for all CCM specimens. CONCLUSION: The CCM technique tested in this study utilizing 4 measurements on target-shade tabs could reproduce tooth color gradation from incisal to precervical regions with clinically acceptable results.

Analysis of Variance↗

PubMed2006

Effect of esthetic core shades on the final color of IPS Empress all-ceramic crowns.

STATEMENT OF PROBLEM: Clinically relevant assessment of all-ceramic crowns supported by esthetic composite resin foundations has not been evaluated with regard to color reproducibility. PURPOSE: This in vitro study quantitatively evaluated the influence of different shades of composite resin foundations and resin cement on the final color of a leucite-reinforced all-ceramic material. MATERIAL AND METHODS: A total of 128 disks were fabricated; 64 (20 x 1 mm) were made of all-ceramic material (IPS Empress) and 64 (20 x 4 mm) of 4 different shades composite resin (Tetric Ceram). The ceramic and composite resin disks were luted using 2 shades (A3 and Transparent) of resin cement (Variolink II). Color was measured using a colorimeter configured with a diffuse illumination/0-degree viewing geometry, and Commission Internationale de l'Eclairage (CIE) L( *)a( *)b( *) values were directly calculated. Descriptive statistical analysis was performed, and color differences (DeltaE) for the average L( *), a( *) and b( *) color parameters were calculated. Repeated measures analysis of variance (ANOVA) was used to compare mean values and SDs between the different color combinations (alpha=.05). RESULTS: The CIE L( *)a( *)b( *) color coordinate values showed no significant differences for variation in color parameters due to the effect of the different composite resin shades (P=.24) or cement shades (P=.12). The mean color difference (DeltaE) value between the groups was 0.8. CONCLUSION: Within the limitations of this study, the use of different shades for composite resin cores and resin cements presented no statistically significant effect on the final color of IPS Empress all-ceramic material.

Acrylic Resins↗

PubMed2003

Effects of various finishing systems on the surface roughness and staining susceptibility of packable composite resins.

OBJECTIVES: The purpose of the present study was to investigate the influence of various finishing systems on the surface roughness and staining of three packable resin composites and a conventional microhybrid one. METHODS: Three packable composites (Solitaire-Heraeus-Kulzer, ALERT-Jeneric-Pentron, SureFil-Dentsply) and a conventional microhybrid (Z250-3M-ESPE) were used. Composite specimens were prepared and polished with Poli I and Poli II aluminum oxide pastes, Ultralap diamond paste, Enhance finishing points, Politip rubber polishers, fine and extra fine diamond burs, and 30-blade tungsten carbide burs according to the manufacturers' instructions. The polished surfaces were evaluated with a profilometer, and then immersed in 2% methylene blue for 24h. Afterwards, the specimens were prepared for the spectrophotometric analysis. Results were statistically analyzed by ANOVA and Tukey test. RESULTS: Significant differences were found for the surface roughness and staining recorded, with interaction among composite resins and the finishing systems used. No correlation was found between surface roughness and staining susceptibility (p=0.5657). SIGNIFICANCE: For most of the polishing agents used, Z250 presented the smoothest surfaces and the least dye uptake. ALERT presented the roughest surfaces, and Solitaire, the highest dye concentration. The smoothest surfaces were not necessarily the most stain resistant. Staining is highly influenced by each composite monomer and filler composition.

Analysis of Variance↗

PubMed2000

In vivo measurement of colour changes in natural teeth.

It has been observed that teeth become lighter when they are dried. The present study was designed to quantify these changes and the time taken for tooth colour to return to normal. The colour of an upper central incisor in each of seven subjects was measured using a reflectance spectrophotometer before and after application of a rubber dam and, in another seven subjects before and after taking a polyvinylsiloxane impression. There were statistically significant changes in the L*, a* and b* values following rubber dam application and in the L* value following impression taking. The results demonstrate that teeth become brighter and less colour saturated after rubber dam application and brighter after impression taking. The original values were regained after 30 min.

Color↗

PubMed1996

Color stability of heat-activated and chemically activated fluid resin acrylics.

PURPOSE: Heat- and chemically activated acrylics processed by compression molding or fluid resin matrix techniques for fabrication of partial dentures were evaluated for color stability by reflection spectrophotometry after accelerated aging. MATERIALS AND METHODS: Samples of heat-activated (L199, PDON, SB) and chemically activated (PR, PVAR, SC) denture base acrylics were polymerized according to manufacturers' instructions. Samples were aged in an artificial aging chamber, and color was measured by CIE L*a*b* on a reflection spectrophotometer at baseline and after each of three aging cycles. RESULTS: At 450 kJ/m2, color changes of two chemically activated acrylics (PR and SC) were perceptible. PR became less red, whereas SC became darker and more yellow. The most color-stable acrylics were a heat-activated resin (SB) and one chemically activated acrylic (PVAR). CONCLUSIONS: The three heat-activated acrylics tested were more color-stable than two of the chemically activated acrylics, but one chemically activated acrylic (PVAR) recommended for a fluid resin matrix technique was color-stable.

Acrylic Resins↗

PubMed2005

Bleaching-induced colour change in plastic filling materials.

The purpose of this in vitro study is to compare the colour changes of five different tooth-coloured restoratives: Ormocer (Definite/Degussa), compomer (Dyract AP/Dentsply De Tray), packable composite (Filtek P60/3M), flowable composite (Filtek Flow/3M) and hybrid composite (Filtek Z250/3M) after two different bleaching regimens [Vivastyle (10% carbamide peroxide)/Vivadent and Crest Professional Whitestrips (6.5% hydrogen peroxide strip bands)/Procter & Gamble]. Fifteen specimens of 30 x 30 x 2mm(3) size were fabricated from each material and randomly divided into three groups of five. Specimens in group one were stored in distilled water at 37 degrees C for two weeks and served as control. Group two specimens were treated with Vivastyle for two hours per day for two weeks and group three specimens were treated with Whitestrips for 30 min twice daily for two weeks. During the test period the specimens were kept at 37 C and in 100% relative humidity. At the end of the bleaching regimens colour measurements of the control and test groups were made with UV visible recording spectrophotometer. Colour changes were calculated with the use of the CIE-LAB uniform colour scale and compared by the use of Kruskall-Wallis test, followed by the Mann-Whitney U test. Control, Vivastyle and Whitestrips L*, a* and b* values differed significantly for all materials except Filtek Z250 (p < 0.05). All restorative materials demonstrated significantly higher colour change (DeltaE) with Whitestrips (p < 0.05). Dyract AP demonstrated the highest colour change both for the bleaching regimens followed by Filtek Flow, Definite, Filtek P60, and Filtek Z250 showed the smallest colour change. Colour change of plastic restorative materials during bleaching is both filling material and bleach specific.

Color↗

PubMed2003

Color change in acrylic denture base resin reinforced with wire mesh and glass cloth.

In this study, the L*a*b* color system as a color system and light transmittance of the denture base resin reinforced with wire mesh and glass cloth were measured, and the color difference (deltaE*ab) was calculated using L*, a* and b* values which were measured both on a white calibration plate and on a null background. The thicknesses of test specimens, which were reinforced with wire mesh and glass cloth 0.5 and 1.0 mm below the surface, were 3 and 5 mm. L*, a* and b* values of wire mesh reinforcing specimens decreased in comparison with the non-reinforcing specimens (p<0.05). L* values of glass cloth-reinforcing specimens increased compared with the non-reinforcing specimens (p<0.05). The glass cloth is an effective reinforcing material and an aesthetically important property of denture base resin, since wire mesh makes the resin appear darker with the background condition greatly altering the color, while glass cloth makes the resin lighter.

Acrylic Resins↗

PubMedDate not supplied

Color stability of a resin-modified glass ionomer cement.

The color stability of a resin-modified glass ionomer cement (Fuji II LC) was investigated over six months using colorimetry. Five shades (A2, A3, A4, B3 and C4) were selected and 10 square specimens (7 mm wide and long, and 1.5 mm deep) were made for each shade using special grit molds. CIE L*, a*, b* color parameters of the specimens were taken at one day, one week, one month, three months and six months. Results were subjected to MANOVA and ANOVA/Scheffe's test at significance level 0.05. The effects of time on color parameters (L*, a*, b* values) were found to be shade dependent. All shades exhibited a decrease in L* values over time. With the exception of shade B3, significant differences in L* values were observed at six months. A general decrease in b* values was also observed but differences among the various time intervals were not significant except for shades A3 and C4. No apparent trends were observed for changes in a* values. For all shades, the largest color change (delta E) was observed between one day and one week. The color stability of the resin-modified glass ionomer investigated was shade dependent. A general decrease in lightness and yellow chroma was observed.

Analysis of Variance↗

PubMed1999

[Study on relationship of different thickness and opaquing capacity of various opaques].

OBJECTIVE: To evaluate the relation between different opaque thickness and color difference. METHODS: Model made of the thin plastic paper was used to control the ceramic thickness. The data of chromaticity was measured by TC-PIIG auto color difference meter and its results were processed by computer. RESULTS: There are two thickness values which can be considered as ideal range of opaque thickness for color opaquing: one is the values of ceramic thickness which is based on the color difference values of the infinite chromaticity thickness (ICT) and the other is the values of ceramic thickness which is depended on the color difference values which is 1.5 compared with ICT. The ideal range for VITA is (0.207-0.152) mm, SHOFO is (0.190-0.160) mm, CARAT is (0.140-0.074) mm and EXCELCO is (0.169-0.144) mm. CONCLUSION: There is a relationship of non linear direct ratio between opaque thickness and its shadow capacity. However, no more increase of color difference values in respect to the thickness was found when the ceramic thickness reach a certain value. Different ceramic porcelain needs different ideal range of thickness.

Ceramics↗

PubMed2003

Shade matching in restorative dentistry: the science and strategies.

Closely matching natural teeth with an artificial restoration can be one of the most challenging procedures in restorative dentistry. Natural teeth vary greatly in color and shape. They reveal ample information about patients' background and personality. Dentistry provides the opportunity to restore unique patient characteristics or replace them with alternatives. Whether one tooth or many are restored, the ability to assess and properly communicate information to the laboratory can be greatly improved by learning the language of color and light characteristics. It is only possible to duplicate in ceramic what has been distinguished, understood, and communicated in the shade-matching process of the natural dentition. This article will give the reader a better understanding of what happens when incident light hits the surface of a tooth and give strategies for best assessing and communicating this to the dental laboratory.

Afterimage↗

PubMed1997

Optimizing the esthetics of Class IV restorations with composite resins.

Direct bonding is the most commonly-used treatment for the conservative esthetic restoration of anterior teeth. Class IV defects deserve special attention because of their high incidence in anterior teeth. One of the major challenges for the practitioner treating defects in this category is disguising the fracture line, through the correct use of masking and restorative resins, to make the restoration imperceptible to the eye. This paper discusses the morphologic, histologic, and optical characteristics, as well as the polychromy of sound natural teeth, and the way they correlate with composite restoratives.

Color↗

PubMed2003

[A study on the color difference between Au-Pt alloy porcelain and Ni-Cr alloy porcelain].

OBJECTIVE: To investigate the color difference between Au-Pt alloy porcelain and Ni-Cr alloy porcelain. METHODS: 30 metal-ceramic specimens with different dentin porcelain thickness were fabricated with two types of metal-ceramic alloy, each type of alloy had 15 specimens. L*, a*, b* were measured after opaque porcelain was applied, and dentin porcelain was fired 1, 3, 5, 7 times by MINOLTA CR-100. Then delta E was calculated which reflected the color difference between high-gold alloy porcelain and Ni-Cr alloy porcelain. RESULTS: Comparing with Ni-Cr alloy porcelain, the color of Au-Pt alloy porcelain was reddish, yellowish and less bright. The delta E between high-gold alloy porcelain and Ni-Cr alloy porcelain in shade A2 was largest when opaque porcelain was applied. It decreased when dentin porcelain was applied. It became smallest when fired 3 times, and increased along with the increase of fire times. It was larger than 1.5 except firing 3 times. When dentin porcelain was applied, delta E which was larger than 1.5 among different dentin porcelain thickness decreased along with the increase of dentin porcelain thickness. CONCLUSION: The color difference between the two types of metal-ceramic alloy should be carefully taken into account in order to improve the quality of color matching.

Chromium↗

PubMed2007

Changes in color and color parameters of dental resin composites after polymerization.

OBJECTIVES: The objectives were to measure the color change of varied shades of dental resin composites after polymerization, and to determine the correlation among the polymerization color change and the changes in color parameters after polymerization. METHODS: Eight light-curing resin composites, a total of 41 shades, were studied. Color of specimens (1 mm in thickness) was measured on a reflection spectrophotometer before and after polymerization over a white background. Changes in color (Delta E*(ab)), and color parameters (Delta L*, Delta C*(ab), Delta a*, and Delta b*: value after polymerization - value before polymerization) were calculated. RESULTS: The range of changes in each shade of resin composites was 1.1-7.9 for color (Delta E*(ab)), -7.5 to 2.3 for Delta L*, -6.8 to 3.1 for Delta C*(ab), -0.9 to 1.2 for Delta a*, and -6.8 to 3.1 for Delta b*. Delta E*(ab), Delta L*, Delta C*(ab), Delta a*, and Delta b* were influenced by the brand and shade of resin composites, and there was a significant interaction between two independent variables (p < 0.05). On the basis of the multiple regression analysis, in which Delta E*(ab) after polymerization was set as a dependent variable and Delta L*, Delta C*(ab), Delta a* and Delta b* as independent variables, multiple correlation coefficient (r) was 0.842 and the included predictors were Delta L* [standardized partial correlation coefficient (beta) = -0.760] and Delta C*(ab) (beta = -0.715). This result indicated that the polymerization changes in color and color parameters were varied by the brand and shade of resin composites, and the polymerization color change was caused by the changes in lightness and chroma with the similar power of influence.

Color↗