The dimensions of color related to dental porcelain and translucency.
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The objective of this study was to compare the aesthetic properties of color and translucency of Vita shade-based tooth-colored restorative materials, including composite resins, a polyacid-modified composite resin, and resin-modified glass-ionomer cements via clinical discrimination by human evaluators. The hue/chroma, value, and translucency of the five different materials chosen to represent the range of commercially available tooth-colored restoratives were graded by 40 dental personnel against the body of their respective Vita shade tabs using a five-point scale (1 = very poor; 2 = poor; 3 = average; 4 = good; 5 = excellent). Results confirm the clinical observation that the hue/chroma, value, and translucency of the different materials evaluated do not match the Vita shade guide to which they are supposedly keyed. The aesthetic properties of hue/ chroma, value, and translucency for the material evaluated were all shade dependent. Comparison of pooled results revealed that none of the materials had good or excellent ratings and that the composite resins had significantly better hue/ chroma, value, and translucency match to the Vita shade guide than the other materials evaluated.
Recent advances in ceramic technology have revolutionized aesthetic dentistry. When treating a single anterior tooth in need of a full-coverage restoration, a multitude of options in restorative materials and techniques is available to the clinician. The learning objective of this article is to present and evaluate a selection of all-ceramic dental materials currently available for aesthetic full-coverage crown restorations. When selecting an all-ceramic system, there are several major factors to consider, including the inherent translucency of the ceramic material and of the adjacent dentition, the color of the prepared tooth, and the forces anticipated in that region. Preparation and restoration of discolored and nondiscolored tooth structure are reviewed. The techniques presented can be utilized to obtain predictable results in the anterior region for aesthetic all-ceramic full-coverage restorations.
Many in the dental profession believe that accurate shade matching of the single anterior tooth is impossible. Fabricating an anterior porcelain crown to accurately match surrounding teeth is the most difficult task in our industry. However, it is not impossible. For many years, I took custom shades for a large dental group, and while there were many successes, there were also many failures. In one incident, the dentist, his team and I all agreed on a Vita Lumin A-2 for a patient. I attended the try-in. To everyone's surprise, the crown did not match the patient's natural teeth. After taking a new shade and delivering the new crown, the shade matched more closely, but still "no cigar." This particular failure resulted in the loss of a patient. Unfortunately, this was one of several incidents involving a mismatched shade and unsatisfied patient. These experiences caused me to question the techniques I was using. From them, I developed a technique for taking shades which could be shared with others to eliminate the frustrations we have all encountered.
PURPOSE: The purpose of this study was to investigate the distribution of shades selected for metal ceramic crowns provided at a dental teaching hospital. MATERIALS AND METHODS: Data on the selection of shade for 2,500 metal ceramic crown units, placed over a 5-year period at the University Dental Hospital of Manchester, were collected and analyzed. Only those crowns placed adjacent to minimally restored vital teeth were included in the study. RESULTS: The results indicate that the most frequently chosen shades were in the mid-range of reddish-brown hue. Furthermore, shades in the reddish-grey range of hue were rarely chosen. The selection of more than one shade for a crown ("mixed shades") was generally restricted to the maxillary anterior teeth. CONCLUSION: Knowledge of the distribution of shades selected for permanently luted metal ceramic crowns may be a useful adjunct in shade selection, particularly for the inexperienced operator.
In cases, in which not only the globe of the eye, but the whole conjunctival sack is missing and the eyelids are due to scarring attached either to the orbital tissues and/or to each other, it is not possible to insert a prosthesis. This is a major aesthetic defect. The cavity that allows artificial eye insertion can be formed by surgery. One of the best methods is the orbital cavity reconstruction developed and suggested by the Hungarian István Csapody. He constructed two instruments to perform the operation: a butterfly shaped marker to prepare skin graft with proper size and shape, and an adjustable cone formed spacer to keep the reconstructed socket open during the healing process. We use free autologous split skin graft to line the cavity. If the shapes of the eyelids are intact, and the color of the prosthesis matches the fellow eye and it fits perfectly, then the postoperative cosmetic result can be excellent.
PURPOSE: To determine the color stability of five composites after light-curing and recommended post-curing using reflection spectrophotometry. MATERIALS AND METHODS: Samples of the composites were prepared as disks 10 mm in diameter and 1 mm thick. The pre-cured samples were prepared with a clear plastic sheet on the top and bottom of disk, pressed between two glass slabs to the thickness of the mold, and then removed from between the glass slabs. The color of the samples was measured with the clear plastic sheets in place. The color of the composites before curing served as the control. RESULTS: Light-curing caused barely perceptible to perceptible color changes for all of the composites from the pre-cured shade. Clearfil and TrueVitality changed color significantly more than Charisma, Conquest C&B and Herculite XRV. Once the composites were light-cured, post-curing caused no further perceptible changes in shade.
Porcelain restorations have double-layer color effects resulting from the presence of body and opaque layers. The purpose of this study was to quantify the color differences resulting when a defined thickness of body porcelain is fired on an opaque porcelain of the same shade designation and from the same porcelain brand. A color difference coefficient was defined as the color change resulting from a 1-mm-thick layer of body porcelain on an opaque porcelain of the same shade and brand. Six shades and four porcelain brands were evaluated in this study. The range of color difference coefficients for all shades and brands was 6.76 to 14.32. There was no significant difference between shades or between brands. The use of color difference coefficients is a practical method of evaluating porcelain shades and brands and should provide guidance in the choice of porcelains and the fabrication of porcelain restorations to better achieve the desired esthetics.
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The shades of several tooth-colored restoratives are now keyed to the Vita Lumin shade guide. The purpose of this study was to determine whether manufacturers' shade guides had color attributes that were similar to the Vita Lumin guide to which they are supposedly keyed. The overall color accuracy between the different guides was also compared via colorimetry. Results showed that none of the manufacturers' shade tabs evaluated had all L*, a*, and b* values that were identical to their respective Vita shade tabs. For the shades evaluated, manufacturers' tabs were generally darker than their corresponding Vita shade tabs. When shade guides were compared, the color accuracy of Z100 and Fuji II LC shade guides was significantly better than that of Durafill VS and TPH. Dyract's shade guide was the most accurate and was significantly better than the shade guides of Fuji II LC, Durafill VS, and TPH. The accuracy of manufacturers' shade guides was not consistently product dependent but was shade dependent.
STATEMENT OF PROBLEM: Use of temporary crowns and fixed partial dentures is especially relevant when the treatment plan requires restorations for long interim periods, and the in-service discoloration of provisional restorative materials is a major drawback. PURPOSE: This study evaluated the discoloration effect of coffee and tea on some materials that are commonly used in the fabrication of provisional restorations. MATERIAL AND METHODS: Six commercially available provisional resins (Jet, Caulk TBR, Protemp Garant, Luxatemp Solar, Provipont DC and SR-Ivocron-PE) were evaluated after 1 day, 7 days, and 30 days of immersion in various staining solutions. Color measurements were obtained by using a Dr Lange Micro Color tristimulus colorimeter and color differences (delta E*) were estimated. RESULTS: The 2 chemically activated resins (Jet and Caulk TBR) and the heat-cured resin (SR-Ivocron PE) exhibited the least color changes, whereas the Provipont-DC resin was the least color stable. After immersion for 30 days, the combination with the coffee solution resulted in unacceptable discoloration for all the tested materials. CONCLUSIONS: Provisional restorative materials, staining solutions, and immersion time were significant factors that affected color stability. After immersion for 7 days, all materials showed observable color changes. The composite-based materials, especially light-curing composites, were the least color stable. The coffee solution exhibited more staining capacity than the tea solution.
STATEMENT OF PROBLEM: Visual color matching to determine shades in dentistry is inconsistent and unreliable. If accurate, instrumental measurement of tooth color would provide objective, quantified data to match natural teeth to clinical shade guides. PURPOSE: This study evaluated and compared the ability of a new computerized colorimeter and a simple visual test to match ceramic shade guide teeth. MATERIAL AND METHODS: Thirty-one (n = 31) observers with normal color vision were allowed unlimited time to match one set of Vita Lumin shade guide teeth to the corresponding shade guide teeth of a second Vita Lumin shade guide. The same test was administered to 14 of the observers several months later to determine within-subject variability. A computerized colorimeter (Colortron II) equipped with a positioning guide was used to measure the middle third of each shade guide tooth. Through a "match tool" present in the computer's software, readings from one shade guide were matched with readings of the other shade guide by using CIELAB measurements and DeltaE values. The mean number of correct matches by the colorimeter and of correct matches in visual test were compared with a 1-tailed t test. Repeatability for both tests was determined with a paired t test. RESULTS: The Colortron II instrument correctly matched 8 of the 16 tabs (50% correct), whereas visual matching by examiners averaged 7. 7 of 16 correct matches (48% correct) (standard deviation 2.7). No statistically significant differences existed between the 2 methods. The colorimeter demonstrated 100% repeatability and the visual test demonstrated fair repeatability (correlation coefficient r =.60). CONCLUSIONS: Shade determination by visual means was inconsistent. Accuracy of a new colorimeter in matching porcelain shade guide teeth was only slightly better.
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*).
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.
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.
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.