PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Prosthesis Coloring”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources
PubMed2003

Simplified techniques for the placement of stratified polychromatic anterior and posterior direct composite restorations.

Although many tooth-colored indirect restorative materials are available, dentists frequently employ direct composite resins as a primary tooth-colored restorative material. Direct resin systems that are suited for stratification, or layering of various opacities and colors of dental composite, offer dentists the opportunity to accurately reproduce natural teeth in ways that rival the esthetics of most indirect systems. This article presents a simplified version of the classical three-layered technique originally described by Dietschi, and demonstrates the application of a recently introduced composite resin system.

Adult↗
PubMed1994

[Color determination in dental ceramics].

Determining the appropriate color of an esthetic restoration is an important step in dental treatment. In this study instead of a shade guide the validity of a recently available objective colorimeter Castor has been investigated. A porcelain-fused-to-metal porcelain (PFM) (Biodent B2), the sinter-porcelain Mark II and the glass-porcelain Dicor have been spectrometrically studied, as well as a Vita shade guide. The Castor equipment has been used for all measurements. The lightness (L*) of the PFM porcelain was not altered by the glaze firing, whereas the red-green-values (a*) tended towards red and the blue-yellow-values towards blue. Total color value (E*) and lightness (L*) of Mark II and Dicor decreased with rising thickness of the samples. At and above a thickness of 1.5 mm, the background had only marginal influence on the L*a*b*-values. It was noticed, that the order by decreasing lightness within the shade guide did not meet official manufacturer declarations, whereas color intensity correlated evidently with the specification. The Castor equipment for color determination is an interesting innovation in dentistry. For the first time and in an economic reasonable frame it permits objective evaluation of color characteristics, such as lightness (L*), red-green (a*) and yellow-blue (b*).

Color↗
PubMed1996

Color differences between resin composites and shade guides.

The color of manufacturers' shade guides was compared with the color of the actual resin composites. Five light-activated resin composite products were evaluated. Resin specimens and shade guides of same thickness were measured with a spectrophotometer. Color differences (delta E* values) were more than perceptible in all products. The mean delta E* values were least in Z100 and greatest in Herculite XR. Generally, the L* and b* values of the shade guides were higher than those of the resin composites. Some colors showed color differences greater than the acceptable level.

Color↗
PubMedDate not supplied

Gold color in dental alloys.

This article will help the dental laboratory with alloy selection by exploring how the relationship among color, ductility and strength applies to gold and how color can be quantified. Because higher quality materials translate into higher profits, upselling to the dentist and patient is also discussed.

Color↗
PubMed1998

Shade selection: problems and solutions.

This article introduces shade selection as an act of communication rather than a quasi-science that has failed for generations. The use of three simple items: the Pensler Shield, the Kodak Color Viewing Light Selector Card (P3-180), and a patient-oriented prescription form solve the major problems in shade selection. Shade selection must be taught with an understanding of the psychology of vision and a communication of what you think you see.

Color↗
PubMed2000

Color stability of new-generation indirect resins for prosthodontic application.

STATEMENT OF PROBLEM: Several new-generation indirect resins are being advocated for full contour restoration of teeth. Previous indirect resin systems have failed in this application, due in part to color instability. PURPOSE: This study evaluated and characterized the color stability of various new-generation indirect resins (ceramic-polymers) when subjected to accelerated aging. MATERIAL AND METHODS: Four new-generation indirect resin systems, 1 direct resin system, and 1 dental porcelain control were subjected to accelerated aging for a period of 300 hours. Initial specimen color parameters were determined in the Commission International de l'Eclairage Lab (CIELAB) color order system with a colorimeter. Color changes (DeltaE) were calculated between baseline color measurements and measurements made after 150 and 300 hours of accelerated aging. Color difference data were subjected to a 1-way analysis of variance to examine the interaction between material and time interval of aging. Where significant interactions occurred, a least-squared means test was performed to identify differences in the color stability between the materials (P </=.05). RESULTS: After 300 hours of accelerated aging, color changes of the indirect resins ranged between 0.62 and 3.40 DeltaE units. Two of the products tested demonstrated color stability that was not significantly different from the porcelain control. CONCLUSION: All the indirect resins tested demonstrated color stability at or below a quantitative level that would be considered clinically acceptable. Color changes of ceramic-polymers occurred because of changes in chroma, rather than alterations in lightness.

Analysis of Variance↗
PubMed1996

Color stability: denture base resins processed with the microwave method.

Several quick heat-cured denture base resin systems and microwave processing resins have been introduced to provide easier and faster processing. The microwave processing method is the fastest of the heat-cured processing methods. Conventional acrylic resins processed with the microwave method seem to possess adequate physical properties, and one study indicated that a microwave acrylic resin was reasonably color stable under conditions of accelerated aging, although manufacturers do not recommend using them for microwave processing. The purpose of this study was to evaluate the color stability of seven conventional and one microwave heat-cured denture base materials processed with the microwave method. The samples were subjected to conditions of accelerated aging to test for color stability. The color stability was quantitatively measured and color measurements were made before weathering and at 300, 600, and 900 hours. The mean color change for each sample group was statistically analyzed with polynomial regression to determine the pattern of color change over time. The differences in color change for the acrylic resins were significant for all materials, but the color change for Lucitone Hy-pro was not noticeable on visual examination. The results of this study revealed that color changes occurred after accelerated aging in heat-cured denture base resins and Acron GC microwave acrylic resins processed with the microwave method. Hy-pro and TruTone materials exhibited the least color change; Hy-pro material was the most color stable material.

Acrylic Resins↗
PubMed2001

Curing depth of different shades of a photo-activated prosthetic composite material.

This study determined the depth of cure of different shades of a prosthetic composite material with the aim of evaluating the influence of shade variation on post-curing material properties. Four light shades having small tabs (A1, B1, C1 and D2) and four dark shades having higher tabs (A4, B4, C4 and D4) of a prosthetic composite (Artglass) for body paste based on the Vita Lumin Shade guide were selected. Specimens of each shade were exposed with the proprietary photo-curing unit (UniXS) for periods 20, 30, 60 and 90 s. The curing depth of the material for each shade was determined with a scraping technique described by the International Organization for Standardization (ISO 4049), and average values of groups of five specimens were compared using analysis of variance (ANOVA) and Scheffe's S intervals (P < 0.05). The L*a*b* colour parameters of five specimens after 90 s exposure were measured using a small-area dental colorimeter (ShadeEye) in order to determine the colorimetric differences. Three-factor ANOVA revealed that the depth of cure was influenced by shade letter (A, B, C or D) and shade tab (1 and 2, or 4) as well as by the exposure period (P=0.05). Curing depth of the light shades was consistently greater than that of the dark shades. Among the eight shades selected, B1 shade demonstrated the greatest curing depth, while A4 shade exhibited the lowest curing depth. For all shades, longer exposure increased the depth of cure. All of the light shades exhibited higher L* values than any of the four dark shades. Curing depth of the composite material was found to be related to the Vita shade variation and the exposure period.

Analysis of Variance↗
PubMed2002

Influence of abutment substrate and ceramic thickness on the colour of heat-pressed ceramic crowns.

All-ceramic crowns made of leucite-based heat-pressed ceramics are widely used to restore non-vital teeth in conjunction with various post and core materials. However, as some light passes through the ceramic, the colour of the abutment substrate can negatively affect the final aesthetic appearance of the all-ceramic crown. In this study, we made background specimens simulating gold-alloy cast posts and other simulating porcelain veneered cast posts, overlaid different thickness of heat-pressed ceramic on these background specimens, and measured the shifts in colour. We found that, when the background specimen was a gold alloy, the background colour had an effect on the apparent colour, unless the ceramic was more than 1.6 mm thick. When the background specimen was porcelain veneered, the background colour had no evident effect, even when the ceramic was not very thick. Therefore, when making a restoration using a leucite-based heat-pressed ceramic crown, it is advisable to use tooth-coloured materials such as a porcelain veneered cast post, if you will not be able to make the ceramic more than 1.6 mm thick.

Aluminum Oxide↗
PubMed2000

[Effect of titanium substructure on color of porcelain-fused-to-titanium restoration].

OBJECTIVE: To study the effect of titanium substructure on color of porcelain-fused-to-metal restoration. METHODS: Standard samples of Dentsply DETREY-Carat and Tibond porcelain fused-to-metal restorations were made. Color Parameters were tested by cs-5 spectrophotometer. Statistic analysis was done and the color differences were calculated. RESULTS: Most of color parameters were found to be statistically significant at the P < or = 0.05 level at substructure layer. But no statistical significance existed after putting opaque and dentin porcelain. The values of color difference between two groups at opaque and dentin porcelain layers were all smaller than 1.5. CONCLUSIONS: Titanium substructure had no visually apparent effect on final color of porcelain-fused-to-metal restoration. There was no perceived color difference between corresponding shade of two Dentsply porcelain systems (DETREY-Carat and Tibond).

Color↗
PubMed1996

Porcelain veneer color blending.

Matching the color of porcelain veneers to existing teeth has proved to be a challenge for the restorative dentist. The resulting color of a veneer depends upon several factors. This paper reviews a technique for making a test veneer to predict with accuracy the color of the result.

Color↗
PubMed1994

Assessing shade differences in acrylic resin denture and natural teeth.

Four experiments in this study assess shade differences in acrylic resin denture and natural teeth. The first two examine the perceptual errors made by experienced dentists in their use of a manufacturer-provided shade guide for acrylic resin denture teeth. In the first of four experiments, dentists examine whether the numbering of a selected shade guide corresponds to the arrangement of the tabs from light to dark. In the second experiment, a visual discrimination task determines whether dentists can distinguish shade guide tabs from one another. The results from these two experiments revealed that the numbered progression of the shade tabs does not correspond to a light-to-dark order, that dentists have difficulty discriminating between several shade tabs, and that the shade tabs can be rearranged on an empirical basis. The third experiment demonstrated how the shade of natural teeth varies by age, gender, and complexion. The Biotone shade guide, rearranged in the manner suggested by the second experiment, was used to make these assessments. The fourth experiment examined whether the shades used for complete dentures were similar to shades found in natural teeth. The results from the last two experiments showed that shade selection can be facilitated by use of a rearranged set of shade guide tabs. The results also reveal that natural teeth significantly and clinically darken with age; however, selections made for denture teeth tend to be relatively constant in color, despite the age of the patient. Differences for gender and complexion do not appear to be clinically significant.

Acrylic Resins↗
PubMed1994

Effects of finishing and polishing procedures on the surface texture of resin composites.

OBJECTIVES: This study was designed to investigate the effects of finishing and polishing procedures on the roughness and color of resin composite surfaces. METHODS: Four composites and three different polishing systems were evaluated. Forty disc (10 mm x 2 mm) specimens of each composite were prepared. Thirty of them were ground wet through 320-grit paper, and the ground surfaces were used as the base line for the finishing procedure. Ten Mylar-covered specimens were used as controls. A color meter was applied to determine the color differences and a roughness meter was used to measure the surface roughness (Ra). RESULTS: Microfilled composite demonstrated significantly less roughness (p < or = 0.01) than hybrid composite systems as tested by ANOVA and Scheffé's tests. Polishing procedures produced a decrease in the roughness, ranging from 26 to 74%. Relative to the shade guide, the mean color difference values for all the composites after polishing were significantly greater than for the controls (p < or = 0.01) and ranged from 1.08 to 8.15 units. A positive relationship between mean color differences and Ra values was determined by regression analysis (r = 0.55). SIGNIFICANCE: A Mylar strip can create a smoother surface than the other types of tested polishing procedures. Because of the greater values in color differences and surface roughness, the shades of tested resin composites were lighter after the polishing procedures. A custom-made shade guide is suggested based on the results of this study.

Acrylic Resins↗
PubMed2003

In vitro color stability, stain resistance, and water sorption of four removable gingival flange materials.

STATEMENT OF PROBLEM: Evaluation of the color stability of materials used for removable gingival flange prostheses may provide information on their serviceability. PURPOSE: This in vitro study compared the color stability, stain resistance, and water sorption of 4 materials commonly used for gingival flange prostheses. MATERIAL AND METHODS: Forty-five cylindrical disks (15 mm in diameter and 10 mm thick) were fabricated out of 1 silicone (Gingivamoll), 1 copolyamide (Flexite Supreme), and 2 heat-polymerized acrylic resins (QC-20 and Vertex). Ten specimens of each material were evaluated by a spectrophotometer after 7, 14, 30, 60, 120, and 180 days of immersion in staining solutions of coffee and tea, whereas specimens placed in water and exposed to air, served as controls. Color differences before staining and after storage periods were assessed. Another 5 specimens of each material were tested for water sorption after 56 days. Data for color change (DeltaE) and weight difference (DeltaW) were analyzed by use of a repeated measures analysis of variance and Scheffe's multiple comparisons (alpha=.05). RESULTS: The coffee solution produced the highest discoloration value in the silicone material (DeltaE=7.31 +/- 0.57, P<.001), followed by the copolyamide (DeltaE=4.22 +/- 0.40, P<.001), and 2 acrylic resins. In the tea solution, the copolyamide had the greatest staining (DeltaE=2.74 +/- 0.56), whereas the other materials had smaller color changes (P<.001). All investigated materials were relatively color stable (DeltaE < 2) when stored in air and water for 6 months. The copolyamide material showed the greatest water uptake, whereas silicone adsorbed the least water (P<.001). CONCLUSIONS: All flange materials tested demonstrated color stability in air and water. However, the color changes of silicone and copolyamide materials stored in coffee solution for 180 days were greater than 3 NBS (National Bureau of Standards) units, which would be characterized as appreciable and considered clinically unacceptable.

Absorption↗