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PubMedDate not supplied

Laboratory communication for esthetic success.

There is no single or simple answer for effective communication between laboratory technician and clinical dentist. Doing the lab work oneself or having an in-house technician may be a distinct advantage to some albeit labor- and perhaps cost-intensive. If the goal of the practicing dentist is to aspire to excellence, it is incumbent upon him or her to produce restorations that fit the teeth well, are shaded correctly and, when indicated, are the same color as the surrounding teeth. Effective communication with the laboratory is critical if any degree of success is desired.

Color↗
PubMed1999

[Color differences between a resin cement and try-in paste].

OBJECTIVE: This study was to measure the color coincidence and difference of resin cement and its try-in paste. METHODS: 3 shades of a resin cement and its try-in paste were measured and analyzed by CIE L*a*b* on a reflection spectrophotometer. RESULTS: For shade 200, vulue of delta E* was less 1.4 in comparison between try-in paste and self-cured resin. CONCLUSION: The try-in paste of shade 200 matched the self-cured resin cement very well, but the try-in paste was lighter and more yellow than the light-cured resin cement. The resin cement of shade 100 was darker and more yellow than try-in paste; resin cement of shade 300 was lighter and more yellow than try-in paste.

Color↗
PubMedDate not supplied

Color comparison of two shade guides.

PURPOSE: The aim of this study was to analyze color parameters and color compatibility of two randomly chosen Vita shade guides, as well as to propose possible clinical guidelines. MATERIALS AND METHODS: Data were recorded using a colorimeter set to standard illuminant source C and the CIE L*a*b* system. A custom adapter system, which allowed a measuring area at the middle third of the tabs, was produced. Each of 42 tabs was recorded one time each on three different days. Color distribution was examined in diagrams whose coordinates were L*a*b* and L*C*H degree color coordinate pairs. Color coordinate ranges and coverage error were examined using the corresponding equations and statistical methods. RESULTS: The method repeatability was approximately delta E* = 0.1. Color difference ranges of Vitapan Classical and Vitapan 3D Master were 14.3 and 19.2, respectively. Color coordinate ranges of Vitapan Classical were as follows: delta L* = 12.8; delta a* = 1.7; delta b* = 9.0; delta C* = 9.0; and delta H degree = 7.4. Corresponding values for Vitapan 3D Master were delta L* = 15.3; delta a* = 3.4; delta b* = 16.3; delta C* = 16.6; and delta H degree = 10.5. Coverage error of Vitapan 3D Master to Vitapan Classical was 1.4 +/- 0.6, while vice versa it was 2.0 +/- 1.5. CONCLUSION: Compared to Vitapan Classical, chromaticity ranges of Vitapan 3D Master were extended in the desired directions: hue was extended toward yellow-red, and saturation was extended toward more saturated tabs. Compared to Vitapan Classical, Vitapan 3D Master tabs were more uniformly spaced. The examined shade guides were found to be color compatible.

Color↗
PubMedDate not supplied

[Study of dental chromatic space].

Dental chromatic space has been the topic for many studies and most of all indicated that dental structures are very versatile from the colour point of view, therefore a proper shade selection is difficult to made. Our study made a comparison between the shades of dental structures of men and women of different ages, the measurements being done in three regions: incisal, middle and cervical. We used a spectrophotometer Spectra-Flash 600 and the PC programme Data-Master version 2.3 for both chromatic determinations and the statistical evaluations. The study proved that there are no major differences between the dental shades of men and women; meanwhile chrome increases with age and from incisal to cervical regions. Also, value increases from incisal to cervical region.

Adolescent↗
PubMed2001

Extraoral maxillofacial prosthetic rehabilitation at the M. D. Anderson Cancer Center: a survey of patient attitudes and opinions.

STATEMENT OF PROBLEM: Measures of satisfaction after extraoral maxillofacial prosthetic rehabilitation have been sparsely reported. PURPOSE: This article reviews the care-related opinions of patients who were provided extraoral prostheses at the M. D. Anderson Cancer Center over the course of 10 years. MATERIAL AND METHODS: A questionnaire was delivered to 263 extraoral prosthetic patients to elucidate their degree of satisfaction with several parameters, including prosthetic use, care, quality, durability, longevity, and cost. In addition, issues relating to self-image, socialization frequency, and income-earning ability before and after rehabilitation were surveyed. RESULTS: The views of 76 respondents demonstrated a general satisfaction with their prostheses. A majority believed that their prostheses fit comfortably, and most were satisfied with cosmesis. In addition, a preponderance of respondents reported no substantial alteration in social activity after rehabilitation. Although the number of respondents relying on their own employment fell by more than 50% after rehabilitation, nearly all reported a relatively static income before and after rehabilitation. CONCLUSION: The survey revealed a high degree of patient satisfaction with extraoral maxillofacial prostheses. Nevertheless, areas of potential improvement were not lost on the survey's population. The patients desired prostheses that last longer and have improved color stability. An interest in improved retentive mechanisms was mentioned by several patients, and only about half of the respondents perceived prosthetic cost to be completely reasonable.

Adult↗
PubMed1995

4-year clinical study of castable ceramic crowns.

PURPOSE: To evaluate the 4-year clinical performance of castable glass ceramic crowns used to restore teeth in the posterior segments. MATERIALS AND METHODS: 101 castable ceramic (Dicor) full++ crown restorations were placed in 61 molar and 40 premolar teeth using a bonded resin cement. RESULTS: After 4 years of clinical performance, 15 of the original 101 restorations were known to have failed with 13 of those failures affecting molar restorations. All serviceable restorations were rated as excellent for color match, margin adaptation, proximal contact and gingival health. Cavosurface margin discoloration received a 93.5% alfa response. The results of this study show that Dicor crowns meet the esthetic and biological requirements for posterior restorations. The incidence of fracture of molar restorations in this study indicated that when used for restoring molars, careful case selection and caution must be employed.

Adult↗
PubMed1999

[Motif expressing soft print lenses. Effect on visual function].

BACKGROUND: Contact lenses which change the structure and color of the iris are used not only for many therapeutic situations but also for cosmetic reasons. The purpose of this study was to investigate whether such lenses cause impairment of visual functions. MATERIAL AND METHODS: In healthy volunteers with an uncorrected visual acuity of 20/20 a clear soft-fitting lens and a special effect soft contact lens (Crazy lens, Bach Optic, Cologne) were tested in changing sequence. The following parameters were studied: visual acuity, contrast sensitivity (MCT 8000, VisTech Cons., Dayton, Ohio), Goldmann visual field, mesopic vision (Nyktometer, Rodenstock, Munich), and subjective wear comfort on a scale from 1 (excellent) to 10 (poor). Statistical analysis was performed using the Wilcoxon test and the Mann-Whitney U-test. RESULTS: Nine volunteers with a mean age of 29.9 +/- 5.1 years were analyzed. Visual acuity was reduced to 0.9 +/- 0.23 in the Crazy lens group compared to 1.2 +/- 0.13 in the clear lens group. Mesopic vision without glare was reduced from 1:2.5 to 1:7.4. Goldmann visual field displayed a significant constriction of following isopters: III/4, I/4, and I/3. Contrast sensitivity was significantly reduced in a photopic condition with and without glare and in a scotopic condition without glare; there was, however, an increase in contrast sensitivity in a scotopic condition with glare. Furthermore a decrease in wear comfort from 2.8 +/- 1.4 with the clear fitting lens to 5.7 +/- 2.1 with the print-lens was found. CONCLUSION: The tested special-effect contact lenses are associated with a reduction of many visual functions, including visual acuity and contrast sensitivity. This may interfere in some wearers with the ability to drive a car.

Adult↗
PubMed1994

Influence of P205, AgNO3, and FeCl3 on color and translucency of lithia-based glass-ceramics.

OBJECTIVES: The objective of this study was to characterize the influence of various metals, metal compounds, and P2O5 as a nucleating agent on the color and translucency of a Li2O-Al2O3-CaO-SiO2 glass-ceramic. METHODS: Glass frits of Li2O-Al2O3-CaO-SiO2 (LACS), LACS with 1 mol% P2O5 (LACSP), and/or LACS with one of 16 colorants were melted, poured into a cylindrical graphite mold, cut into disks, annealed, nucleated, crystallized, and annealed again. Ten translucency measurements of each of five disks were made using a tristimulus colorimeter and a D65 standard CIE illuminant. The color of each disk was analyzed using the CIE L*a*b* color space system (1976) as a function of colorant, colorant concentration, and P2O5. RESULTS: Mean L* values of glass-ceramic disks ranged from 63.5 for LACS containing 6.2 mmol% FeCl3 (LACSP-6.2Fe) to 84.1 for LACS. No significant difference (p > 0.05) was found between the mean L* values for LACS, LACSP, and LACS with 0.19 mmol% AgNO3 (LACS-0.19Ag). The mean contrast ratio of glass-ceramic specimens ranged from 0.42 (LACS and LACS-1.0Fe) to 0.98 (LACS-0.78Ag). Mean color difference values varied from 5.8 (LACSP-1.0Fe vs. LACS) to 36.3 (LACSP-0.78Ag vs. LACSP). SIGNIFICANCE: The results of this study indicate that, because certain colorants in glass-ceramics affect opacity as well as hue and chroma, the development of glass-ceramics should be simplified by: 1) employing a nucleating agent that does not affect hue or chroma significantly, 2) controlling fixed levels of translucency consistent with mechanical and physical property requirements, and 3) varying the hue and chroma by means of colorants that do not affect the crystallization process. This implies that the volume fraction and mean size of crystals must be controlled, since the translucency or opacity of glass-ceramics is associated with scattering of light at the interfaces between adjacent crystals, and between crystals and the glass phase because of differences in refractive indices (McMillan, 1979a).

Analysis of Variance↗
PubMed2006

The effect of enamel porcelain thickness on color and the ability of a shade guide to prescribe chroma.

OBJECTIVE: To test the null hypothesis that there is no color change when enamel porcelain thickness is changed and to evaluate the ability of a shade guide to prescribe chroma. METHODS: Three shades (3M1, 3M2 and 3M3) were selected from a Vitapan 3D master shade guide. Five disk specimens were prepared for each shade, consisting of three layers (opacious dentin, dentin and enamel) at thicknesses of 0.6, 0.8 and 0.6mm, respectively. The color of each disk was measured using a spectrophotometer. Enamel porcelain was reduced in thickness to 0.3mm and porcelain disks were remeasured. RESULTS: Reducing the enamel thickness of porcelain disk specimens significantly increased L) (p<0.05), b*, metric chroma and hue angle (p<0.001). For the three shades studied (3M1, 3M2 and 3M3) L* values were not significantly different (p>0.05) and chroma increased for 3M1 with the lowest chroma to 3M3 with the highest chroma, which is in line with the shade guide specifications. Although statistically significant (p<0.001) changes in hue angle between the three shades were small (less than 3 degrees overall). The difference in chroma between the three shades 3M1, 3M2 and 3M3 was greatest for the thin enamel layer than the thick enamel layer. SIGNIFICANCE: A change in enamel thickness from 0.6 to 0.3mm resulted in a three-unit change in L* and metric chroma and a 4 degrees change in hue angle. A change in enamel porcelain thickness will have a greater effect on higher chromatic shades than those with lower chroma. The ability of the shade guide to prescribe chroma was demonstrated but this could be offset by an anomalous enamel thickness.

Color↗
PubMed2006

Influence of the amount of UV component in daylight simulator on the color of dental composite resins.

STATEMENT OF PROBLEM: Color of fluorescent substances is influenced by the amount of ultraviolet (UV) component in the illumination. Color of fluorescent dental composite resins may change by the amount of UV component in the ambient light, but there have been few studies on this subject. PURPOSE: The purpose of this study was to determine the differences in color and color parameters such as lightness, chroma, and hue of composite resins created by varying the amount of UV component of a pulsed-xenon source that is conditioned to approximate the Commission Internationale de l'Eclairage (CIE) standard illuminant D65. MATERIAL AND METHODS: A spectrophotometer, in which the UV component of a daylight simulator could be adjusted, was developed. Eight light-polymerized dental composite resins, A3 shade, were studied. Five disk-shaped specimens, 10 x 3 mm, were prepared for each material. Color of specimens was measured on a reflection spectrophotometer over a white background relative to 3 illuminations, which had the same spectral power distribution of the CIE standard illuminant D65 in visible range, but different UV component. D65 indicated the illumination in which the UV component of the pulsed-xenon source was adjusted to the CIE standard illuminant D65 using a UV adjustment tile. UV-EXC indicated the illumination in which the UV component of the source was excluded with a UV filter. UV-INC indicated the illumination in which the UV component was included. Differences in color parameters by the illumination were analyzed with repeated-measures 1-way analysis of variance (ANOVA) by the brand of composite resins. Differences in color (DeltaE*(ab)) and color parameters such as lightness (DeltaL*), chroma (DeltaC*(ab)), and hue angle (Deltah) were analyzed with 3-way ANOVA, with the independent variables of brand of composite resin, combination of illuminations, and type of color parameters (alpha = .05). RESULTS: Color differences (DeltaE*(ab)) by the amount of UV component in the illuminations ranged between 0.3 and 1.4 for D65 and UV-EXC, between 0.3 and 0.5 for D65 and UV-INC, and between 0.2 and 1.6 for UV-EXC and UV-INC. Based on the repeated-measures ANOVA, lightness was not influenced by the amount of the UV component in the illumination, however, chroma and hue angle were influenced by the amount of UV component. Based on the 3-way ANOVA, differences in color and color parameters (DeltaE*(ab), DeltaL*, DeltaC*(ab), and Deltah) by the amount of the UV component were influenced by all of the 3 factors, and there were significant interactions between all the combinations of factors (P < .05). CONCLUSION: Though there were significant differences in color and color parameters by the amount of the UV component in the D65-simulated xenon source, color difference caused by the UV component was lower than 1.6, which is in the visually acceptable range.

Analysis of Variance↗
PubMed1999

Color stability of denture base acrylic resins in three food colorants.

STATEMENT OF PROBLEM: Three commonly used artificial dyes in food technology are erythrosine, tartrazine, and sunset yellow. PURPOSE: The color stability of 5 commercially available denture base acrylic resins (QC-20, Meliodent, Trevalon, Trevalon High, and Lucitone) was studied in vitro. METHODS: The specimens were exposed to 3% erythrosine, tartrazine, and sunset yellow solutions at 23 degrees C +/- 1 degrees C. Color changes were determined with a computer-controlled spectrophotometer. Five specimens from each material were processed, and initial color measurements were made after 1, 3, and 6 months of exposure to the staining solutions. Finally, the color stability was quantitatively measured again, and color differences (DeltaE) were calculated. RESULTS: For the observations made in 1, 3, and 6 months intervals, the specimens that exhibited the least color change were in the sunset yellow solution. The greatest color changes observed according to the National Bureau of Standards unit system were Lucitone (2.71) in erythrosine solution, Lucitone (2.54), QC-20 (1.71) in tartrazine solution, and QC-20 (1.66) in sunset yellow solution. The changes in the other acrylic resins in the 3 solutions were slight and at trace level. CONCLUSIONS: All materials tested were acceptable from the standpoint of color stability for long-term exposure to these food colorants.

Acrylic Resins↗
PubMed1998

Light transmittance characteristics of light-cured composite resins.

OBJECTIVES: The purpose of this study was: (1) to examine the light transmittance characteristics of various shades of light-cured composite resins, and (2) to evaluate the effect of light transmittance characteristics on the color of the resins. METHODS: Eleven shades of two composite resins were used. Specimens with four different thicknesses (0.5, 1.0, 2.0 and 3.0 mm) were prepared. The transmittance at wavelengths from 400 to 700 nm was measured. Also, the color values and the color differences among thicknesses of a specimen on the CIE L*a*b* color system were determined by a digital chroma meter. The differences in the transmittance, color values and color difference were determined by using a one-way analysis of variance (ANOVA) combined with a Tukey multiple-range test. RESULTS: Significant differences were found in the wavelength dependence of transmittance between the two materials, and among shades of each material. The transmittances of the darker shades of one material were significantly lower at lower wavelengths than the other shades, but were nearly equal or significantly higher at higher wavelengths. There was a significant correlation between the changing ratio of transmittance and the color difference. Two materials showed significant differences in delta a* and delta b* of the chromatic component of color difference. SIGNIFICANCE: The results of this study indicate that light transmittance characteristics, including the wavelength dependence, play an important role for the color of a composite resin. The significant difference in light transmittance characteristics among materials and shades will affect their clinical appearance.

Analysis of Variance↗
PubMed2003

Intrarater repeatability of shade selections with two shade guides.

STATEMENT OF PROBLEM: Color research has shown that shade guides do not always represent the color of natural teeth. Moreover, visual evaluation has been found to be unreliable and inconsistent. PURPOSE: This investigation evaluated the effects of 2 shade guides on the intrarater repeatability (reliability) of prosthodontists and general practitioners with regard to shade selection. MATERIAL AND METHODS: Ten prosthodontists and ten general practitioners (all men, 35-45 years old) with an average practice experience of 14 years participated in this study. Examiners were tested to eliminate color blindness. Each clinician used Vita Lumin Vacuum and Vitapan 3D-Master shade guides to determine the shades of the maxillary right canines of 20 patients following a standard protocol. The identification codes of the shade tabs were masked to prevent shade memory. All teeth were polished before each shade selection, and the selection process was standardized for controlled lighting and procedures. Shade selections were randomly repeated 1 month later by the same practitioners on the same group of patients in accordance with the same shade-selection protocol. Analysis of variance and t tests for individual comparisons among means were performed (P<.05). RESULTS: Significant interactions were found between the effects of shade guide system and specialty training on intrarater repeatability (P<.0001, analysis of variance). The intrarater repeatability of prosthodontists was significantly higher than that of general practitioners when the Vita Lumin Vacuum shade guide was used (P<.0001, t test). Use of the Vitapan 3D-Master shade guide significantly improved the intrarater repeatability of general practitioners compared with the Vita Lumin Vacuum shade guide (P<.0005). This improvement was not significant, however, among prosthodontists (P=.2861). CONCLUSION: Within the limitations of this study, the prosthodontists demonstrated superior intrarater repeatability in shade selection, especially when the Vita Lumin Vacuum shade guide was used. Use of the Vitapan 3D-Master shade guide notably improved intrarater repeatability among the general practitioners.

Adult↗
PubMed2006

Shade selection performed by novice dental professionals and colorimeter.

The objective of this study was to test inter-observer variability in shade selection for porcelain restorations, using three different shade guides: Vita Lumin Vacuum, Vita 3D-Master and Procera. Nineteen young dental professionals acted as observers. The results were also compared with those of a digital colorimeter (Shade Eye Ex; Shofu, Japan). Regarding repeatability, no significant differences were found between the three shade guides, although repeatability was relatively low (33-43%). Agreement with the colorimetric results was also low (8-34%). In conclusion, shade selection shows moderate to great inter-observer variation. In teaching and standardizing the shade selection procedure, a digital colorimeter may be a useful educational tool.

Adult↗
PubMed2000

Evaluating porcelain color match of different porcelain shade-matching systems.

PURPOSE: This in vitro study was designed to evaluate the new ShadeEye-EX Chroma Meter and a new visual porcelain shade-matching system (Vitapan 3-D Master, Omega 900) in comparison to the traditionally used visual porcelain shade-matching system (Vita Lumin Vacuum, VMK 68). MATERIALS AND METHODS: Shade matches and porcelain fabrications on individualized shade tabs were carried out. The fabricated porcelain tabs were evaluated against the respective natural tooth using the United States Public Health Service (USPHS) criteria to determine clinically acceptable match. The tabs also were ranked according to the final-color match to the corresponding natural tooth. RESULTS: The percentage of clinically acceptable color matches were as follows: Vita Lumin Vacuum (46.67%), ShadeEye-EX (40%), and Vitapan 3-D Master (56.67%). The generalized estimating equation (alpha = 0.5) showed no statistically significant difference between systems in obtaining a clinically acceptable match (p = .5729). The chi-squared test (alpha = 0.5) showed no statistically significant difference between systems in terms of rank order (p = .5017). The two new systems do not produce color match that is better than the conventional visual porcelain shade-matching system.

Chi-Square Distribution↗
PubMedDate not supplied

Evaluation of a newly developed visual shade-matching apparatus.

PURPOSE: This study evaluated a newly developed visual shade-matching apparatus, Shademat Visual+, as well as the influence of tab arrangement, clinician gender, and years in practice on shade-matching quality. MATERIALS AND METHODS: A group of 129 color-normal evaluators-dental students and general dentists-matched the shade of four ceramometal crowns using the Vitapan Classical shade guide. Crowns were positioned onto the upper member of an artificial head and fastened to the headrest of the dental chair or Shademat Visual+. Shade tabs were arranged according to the manufacturer's suggestion or according to deltaE* in relation to the "lightest" tab and divided into groups (alternative arrangement). The evaluators matched the shade of four ceramometal crowns both in daylight and using the Shademat Visual+ artificial light source. The color coordinates were determined using digital image analysis. Based on deltaE* values, each shade-matching result was ranked from 1 (the worst match) to 16 (the best match) points. RESULTS: The evaluators achieved a better result in Shademat Visual+ trials than in daylight trials (13.2 points vs 12.4 points; P < .001). For the same ceramometal crown, 12.7 points were recorded in daylight trials with the manufacturer-suggested arrangement, and 13.7 were recorded with the alternative arrangement (P< .001). Corresponding values for Shademat Visual+ trials were 13.6 points and 14.6 points, respectively (P< .001). Female-male and student-dentist evaluator differences were not significant. CONCLUSION: The Shademat Visual+ apparatus enabled better shade-matching results than daylight. The alternative tab arrangement enabled better results than the manufacturer-suggested one. Gender and years in practice did not influence shade-matching quality.

Age Factors↗