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William M. Johnston - One of the best experts on this subject based on the ideXlab platform.
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use of a porcelain Color discrimination test to evaluate Color difference formulas
Journal of Prosthetic Dentistry, 2007Co-Authors: Alvin G Wee, Delwin T Lindsey, Kathryn Marie Shroyer, William M. JohnstonAbstract:Statement of problem The natural Tooth Color space reported by a manufacturer may not represent the comprehensive spectrum of natural teeth for all population groups. Purpose The purpose of this study was to define a natural Tooth Color space within the Greater Buffalo, New York population and to compare that to the Color space determined by a manufacturer. Material and methods Nine hundred and thirty-three maxillary central incisors (501 patients) were measured with a shade-taking device (Vita Easyshade). For each Tooth, L*, a*, b* values, chroma, hue, and the closest shade (Vita 3D-Master) were recorded. A linear regression analysis was performed to determine how well the manufacturer's values predict actual values for L*, a*, and b*. Color differences (ΔE*) between the Buffalo population and the closest shade were also calculated. A 1-sample t test was used to determine whether the Color differences seen in the sample were statistically different from the perceptibility threshold, ΔE*=3.7 (a=.05). Results All 3 attributes of the Buffalo population displayed a broader range than those from the shade guide. However, the regression analysis revealed a significantly positive relationship between the L*, a*, and b* values of the 2 methods ( P P Conclusions Color differences between the Buffalo population and the shade guide were frequently above published perceptibility thresholds, but within the range of acceptability. The Buffalo population Tooth Color space encompassed the manufacturer's Color space.
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minimum Color differences for discriminating mismatch between composite and Tooth Color
Journal of Esthetic and Restorative Dentistry, 2001Co-Authors: James C Ragain, William M. JohnstonAbstract:PURPOSE: The purpose of this study was to determine if there are differences between patients and dental professionals in their ability to identify small Color differences (deltaE) in composite resin restorative materials in vitro and to determine the deltaE that would indicate acceptability of Color match between a restoration and an adjacent Tooth. MATERIALS AND METHODS: Subjects were asked to evaluate composite resin disks to distinguish acceptability of deltaE between disk pairs. Color difference discrimination of dental professionals groups D1 (dentists, n = 12) and D2 (dental auxiliaries, n = 12) was compared to that of dental patient groups P1 (patients, n = 12) and P2 (scientists, n = 12). Each group was pretested for normal Color vision. Color differences between a standard and restoration disks of composite were measured in Colour Measurement Committee (CMC) (1:1) Color units. Data were analyzed by logistic regression, and results were used to calculate a probability level for minimal acceptance or rejection of AE for all observers. Mean 50:50 deltaE replacement points (RP) for each group were obtained and analyzed by analysis of variance, and the Tukey pairwise comparison test was applied (alpha = 0.05 for all statistical analyses). RESULTS: There were significant differences found between the experimental groups (p = .020). Group D2 (mean 50:50 deltaE RP = 1.78) proved to be more discriminating in accepting differences between Tooth and composite resin restorative material Color than group P1 (mean 50:50 deltaE RP = 2.69). The mean 50:50 deltaE RP for all subjects was 2.29 CMC (1:1) units. CLINICAL SIGNIFICANCE: The ability to generate an excellent Color match between a Tooth-Colored restoration and the Tooth is critical to esthetic success. This study demonstrates that patients are not as discriminating in their ability to identify small Color differences between composite restorations and the Tooth as are dental professionals. Dental auxiliaries proved to be more discriminating in accepting differences between Tooth and composite resin restorative material Color than were patients.
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evaluating Tooth Color change from carbamide peroxide gel
Journal of the American Dental Association, 1993Co-Authors: Anthony G. Gegauff, Stephen F. Rosenstiel, Kristen J Langhout, William M. JohnstonAbstract:A double-blind experiment assessed the efficacy, longevity and safety of a Tooth whitener in young adults. Significant Color changes occurred after active treatment but were substantially reversed after one week. No permanent changes were found in either pulpal or gingival health.
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Duration of Tooth Color change after bleaching.
The Journal of the American Dental Association, 1991Co-Authors: Stephen F. Rosenstiel, Anthony G. Gegauff, William M. JohnstonAbstract:Tooth Color change was monitored after a single, in-office bleaching technique using a Colorimeter. Twenty young adults participated in the double-blind study at The Ohio State University College of Dentistry. Half of the participants had their maxillary anterior teeth bleached and half were controls. By one month, the large initial Color change was considerably reversed and only noticed by one subject. After six months, the effect of bleaching was small, but still measurable.
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in vitro Tooth Color change with repeated bleaching
Quintessence International, 1991Co-Authors: Stephen F. Rosenstiel, Anthony G. Gegauff, R J Mccafferty, William M. JohnstonAbstract:The interest of patients in vital Tooth bleaching has created a demand for treatment. However, few objective data are available to help determine the number of bleaching appointments necessary and the lightening that can be expected. The purpose of this study was to measure Color changes in bleached extracted teeth and compare these to control groups. Group A was etched and bleached with 35% stabilized hydrogen peroxide. Group B was treated the same as group A, but the bleaching solution was replaced with distilled water. Group C was not treated, but was stored in water. Mean Color difference after one treatment was 3.33 for group A, 1.67 for group B, and 0.48 for group C. After six treatments, the overall Color difference was 3.82, 2.41, and 1.38 for groups A, B, and C, respectively (P less than .01). Color changes beyond those found after the first treatment were small, suggesting that there was little benefit in repeated bleachings under the conditions of this study.
William B. Schwabacher - One of the best experts on this subject based on the ideXlab platform.
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Clinical Evaluation of an Experimental Body Shade Guide Based on In‐Vivo Tooth Color Measurements
Journal of Prosthodontics, 1992Co-Authors: Marie Joycelyn R. Lua, Richard J. Goodkind, William B. SchwabacherAbstract:Purpose The purpose of this study was to develop and evaluate an experimental body porcelain Tooth shade-guide system based on in-vivo Color measurements. This system was tested against two widely used commercial body shade porcelains. Materials and Methods A body porcelain shade guide consisting of 16 tabs was fabricated from available opaques, body, and incisal porcelains and modified with metallic oxide tints. The target Hue, Value and Chroma of these tabs were based on middle-site in-vivo Tooth Color measurements reported by Goodkind and Schwabacher in 1987. Two control groups of body porcelains were fabricated from Ceramco and Bioform porcelains. A new Dental Shade Comparator was used in a clinical test of these tabs in visually matching middle sites of 300 maxillary anterior teeth of 103 subjects. Results The demographic trends in Hue, Value and Chroma were in agreement with those found in the previous study. Four of the 16 experimental body shade tabs were frequently chosen compared with 13 of 16 Ceramco and 3 of 25 Bioform body shades. Intraexaminer and interexaminer reliability tests showed good agreement using the new Dental Shade Comparator. Conclusions The 20 shade tabs that were most frequently selected as a 1st or 2nd choice ranged from 8.25YR to 1.80Y in Hue, 6.45/to 8.00/in Value and/2.05 to/4.15 in Chroma. The new Dental Shade Comparator is a useful tool in the task of shade matching. The current Ceramco II body shades contain many useful porcelains that should be augmented with higher value and with redder, darker shades.
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CLINICAL RESEARCH Clinical Evaluation of an Experimental Body Shade Guide Based on In-Vivo Tooth Color Measurements
1992Co-Authors: Marie Joycelyn R. Lua, Richard J. Goodkind, William B. SchwabacherAbstract:Purpose: The purpose of this study was to develop and evaluate an experimental body porcelain Tooth shade-guide system based on in-vivo Color measurements. This system was tested against two widely used commercial body shade porcelains. Materials and Methods: A body porcelain shade guide consisting of 16 tabs was fabricated from available opaques, body, and incisal porcelains and modified with metallic oxide tints. The target Hue, Value and Chroma of these tabs were based on middle-site in-vivo Tooth Color measurements reported by Goodkind and Schwabacher in 1987.‘ Two control groups of body porcelains were fabricated from Ceramco and Bioform porcelains. A new Dental Shade Comparator was used in a clinical test of these tabs in visually matching middle sites of 300 maxillary anterior teeth of 103 subjects. Resuits: The demographictrends in Hue, Value and Chroma were in agreement with those found in the previous study. Four of the 16 experimental body shade tabs were frequently chosen compared with 13 of 16 Ceramco and 3 of 25 Bioform body shades. lntraexaminer and interexaminer reliability tests showed good agreement using the new Dental Shade Comparator. Conclusions: The 20 shade tabs that were most frequently selected as a 1st or 2nd choice ranged from 8.25YR to 1.80Y in Hue, 6.451 to 8.00/ in Value and 12.05 to 14.15 in Chroma. The new Dental Shade Comparator is a useful tool in the task of shade matching. The current Ceramco II body shades contain many useful porcelains that should be augmented with higher value and with redder, darker shades. J Prosthod 1:74-83. Copyright Q 1992 by the American College of Prosthodontists.
Marie Joycelyn R. Lua - One of the best experts on this subject based on the ideXlab platform.
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Clinical Evaluation of an Experimental Body Shade Guide Based on In‐Vivo Tooth Color Measurements
Journal of Prosthodontics, 1992Co-Authors: Marie Joycelyn R. Lua, Richard J. Goodkind, William B. SchwabacherAbstract:Purpose The purpose of this study was to develop and evaluate an experimental body porcelain Tooth shade-guide system based on in-vivo Color measurements. This system was tested against two widely used commercial body shade porcelains. Materials and Methods A body porcelain shade guide consisting of 16 tabs was fabricated from available opaques, body, and incisal porcelains and modified with metallic oxide tints. The target Hue, Value and Chroma of these tabs were based on middle-site in-vivo Tooth Color measurements reported by Goodkind and Schwabacher in 1987. Two control groups of body porcelains were fabricated from Ceramco and Bioform porcelains. A new Dental Shade Comparator was used in a clinical test of these tabs in visually matching middle sites of 300 maxillary anterior teeth of 103 subjects. Results The demographic trends in Hue, Value and Chroma were in agreement with those found in the previous study. Four of the 16 experimental body shade tabs were frequently chosen compared with 13 of 16 Ceramco and 3 of 25 Bioform body shades. Intraexaminer and interexaminer reliability tests showed good agreement using the new Dental Shade Comparator. Conclusions The 20 shade tabs that were most frequently selected as a 1st or 2nd choice ranged from 8.25YR to 1.80Y in Hue, 6.45/to 8.00/in Value and/2.05 to/4.15 in Chroma. The new Dental Shade Comparator is a useful tool in the task of shade matching. The current Ceramco II body shades contain many useful porcelains that should be augmented with higher value and with redder, darker shades.
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CLINICAL RESEARCH Clinical Evaluation of an Experimental Body Shade Guide Based on In-Vivo Tooth Color Measurements
1992Co-Authors: Marie Joycelyn R. Lua, Richard J. Goodkind, William B. SchwabacherAbstract:Purpose: The purpose of this study was to develop and evaluate an experimental body porcelain Tooth shade-guide system based on in-vivo Color measurements. This system was tested against two widely used commercial body shade porcelains. Materials and Methods: A body porcelain shade guide consisting of 16 tabs was fabricated from available opaques, body, and incisal porcelains and modified with metallic oxide tints. The target Hue, Value and Chroma of these tabs were based on middle-site in-vivo Tooth Color measurements reported by Goodkind and Schwabacher in 1987.‘ Two control groups of body porcelains were fabricated from Ceramco and Bioform porcelains. A new Dental Shade Comparator was used in a clinical test of these tabs in visually matching middle sites of 300 maxillary anterior teeth of 103 subjects. Resuits: The demographictrends in Hue, Value and Chroma were in agreement with those found in the previous study. Four of the 16 experimental body shade tabs were frequently chosen compared with 13 of 16 Ceramco and 3 of 25 Bioform body shades. lntraexaminer and interexaminer reliability tests showed good agreement using the new Dental Shade Comparator. Conclusions: The 20 shade tabs that were most frequently selected as a 1st or 2nd choice ranged from 8.25YR to 1.80Y in Hue, 6.451 to 8.00/ in Value and 12.05 to 14.15 in Chroma. The new Dental Shade Comparator is a useful tool in the task of shade matching. The current Ceramco II body shades contain many useful porcelains that should be augmented with higher value and with redder, darker shades. J Prosthod 1:74-83. Copyright Q 1992 by the American College of Prosthodontists.
Shigemi Ishikawanagai - One of the best experts on this subject based on the ideXlab platform.
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developing a custom dental porcelain shade system for computer Color matching
Journal of Dentistry, 2013Co-Authors: Shigemi Ishikawanagai, Alison Seliger, John D. Da SilvaAbstract:Abstract Objectives This study aims to update the computer Color matching method by generating a new ceramic shade system that covers the entire spectrum of natural Tooth Color and has an efficient design. Methods First, the Color map of 176 maxillary natural incisors and two commercially available and commonly used shade guide systems (Vitapan classic and 3D master) were drawn. Then, 15 shades of layered disks (NW-0: neutral white-0, A1, A2, A3, A4, B1, B4, C4, and D4, and six modifiers; white, pink, grey, blue, cervical-1 and cervical-2, Cerabien ZR) were plotted on the Tooth Color distribution map. Ultimately, 12 target shades were selected around the perimeter of the natural Tooth Color space, and nine different shades were selected within the cluster. By trial and error informed by known formulations published previously, the formulations of Cerabien ZR porcelain powders necessary to achieve these 21 target shades in thickness of 1.0 mm layered on zirconia substrate were then determined and ceramic disks were fabricated. Results Color distribution L *– C * and a *– b * maps showed that new 21 shade system covers a slightly broader range than the natural Tooth distribution, and its distribution is larger than the 3D Master shade's range. Conclusions In the present study, a 21 custom dental porcelain shade system was developed with a 1.0 mm porcelain thickness overlying a zirconia substrate, which can be incorporated into the computer Color matching system. This new shade system has homogeneity with 3D Master, and has a slightly wider Color distribution than that of natural teeth.
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spectrophotometric analysis of Tooth Color reproduction on anterior all ceramic crowns part 1 analysis and interpretation of Tooth Color
Journal of Esthetic and Restorative Dentistry, 2010Co-Authors: Shigemi Ishikawanagai, John D. Da Silva, Aki Yoshida, Lloyd MillerAbstract:ABSTRACT Color matching of a natural maxillary central incisor is one of the most difficult challenges in clinical dentistry. Accurate Color determination and interpretation of Tooth Color information in ceramic work is an important step in achieving success in ideal Color reproduction. In this case study, factors that influence Tooth Color determination were analyzed, and the process of interpretation of Tooth Color information was assessed based on scientific Color data using a novel dental spectrophotometer system. An all-ceramic crown for a maxillary right central incisor was the subject of this Color assessment. The contralateral incisor was an intact natural Tooth that was bleached and then used as the target shade for an all-ceramic crown. The dental spectrophotometer (Crystaleye, Olympus, Tokyo, Japan) was used for Tooth Color measurement and analysis. The target Tooth, prepared Tooth, maxillary arch, and face images were captured for Color information. Tooth Color stabilization related to Tooth bleaching and Tooth dehydration was assessed. Based on Tooth Color data obtained by the dental spectrophotometer, Color was analyzed in several different areas of a Tooth using CIELAB (Commission Internationale de l'Eclarirage) Color coordinates L*, a*, b*, and Color difference ΔE. Interpretation of the Tooth Color information was made in each of porcelain layers on a blue map, and its intensions for Color reproduction were described. Throughout this spectrophotometric assessment, the process of stabilized Tooth Color determination, Tooth Color analysis, interpretations, and fabrication of a blue map for porcelain work was clarified with Color data as scientific evidence. CLINICAL SIGNIFICANCE The use of a dedicated dental spectrophotometer allows the evaluation and measurement of the Color of a bleached Tooth. This allows the laboratory technician to more precisely understand the bleached Tooth shade as well as when the bleached Tooth Color has become stable enough to match to a contralateral all-ceramic crown restoration. (J Esthet Restor Dent 22:42–52, 2010)
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spectrophotometric analysis of Tooth Color reproduction on anterior all ceramic crowns part 2 Color reproduction and its transfer from in vitro to in vivo
Journal of Esthetic and Restorative Dentistry, 2010Co-Authors: Aki Yoshida, John D. Da Silva, Lloyd Miller, Shigemi IshikawanagaiAbstract:ABSTRACT Color reproduction of an anterior Tooth requires advanced laboratory techniques, talent, and artistic skills. Color matching in a laboratory requires the successful transfer from in vivo with careful considerations. The purpose of this study was to monitor and verify the Color reproduction process for an anterior all-ceramic crown in a laboratory through spectrophotometric measurements. Furthermore, a crown insertion process using composite luting cements was assessed, and the final Color match was measured and confirmed. An all-ceramic crown with a zirconia ceramic coping for the maxillary right central incisor was fabricated. There was a significant Color difference between the prepared Tooth and the die material. The die material selected was the closest match available. The ceramic coping filled with die material indicated a large Color difference from the target Tooth in both lightness and chromaticity. During the first bake, three different approaches were intentionally used corresponding with three different Tooth regions (cervical, body, and incisal). The first bake created the fundamental Color of the crown that allowed some Color shifts in the enamel layer, which was added later. The Color of the completed crown demonstrated an excellent Color match, with ΔE 1.27 in the incisal and 1.71 in the body. In the cervical area, Color match with ΔE 2.37 was fabricated with the expectation of a Color effect from the underlying prepared Tooth. The optimal use of composite luting cement adjusted the effect from the underlying prepared Tooth Color, and the Color match fabricated at a laboratory was successfully transferred to the clinical setting. The precise Color measurement system leads to an accurate verification of Color reproduction and its transfer. CLINICAL SIGNIFICANCE The use of a dedicated dental spectrophotometer during the fabrication of an all-ceramic crown allows the dentist and the laboratory technician to accurately communicate important information to one another about the shade of the Tooth preparation, the shade of the contralateral target Tooth, and the influence of luting cement on the final restoration, thereby allowing the technician better control over the outcome of their Tooth Color matching efforts and the final Color match of an all-ceramic restoration. (J Esthet Restor Dent 22:53–65, 2010)
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clinical performance of a newly developed spectrophotometric system on Tooth Color reproduction
Journal of Prosthetic Dentistry, 2008Co-Authors: John D. Da Silva, Hanspeter Weber, Sang E Park, Shigemi IshikawanagaiAbstract:Statement of problem Matching a natural maxillary central incisor to a metal ceramic crown is one of the most difficult challenges in clinical dentistry due to the limitations of dental shade guides and the subjectivity of perceptual evaluation. Purpose The purpose of this study was to assess the clinical effectiveness of a spectrophotometric shade-matching system on Tooth Color reproduction. Material and methods Two metal ceramic crowns were fabricated for a maxillary central incisor for 36 patients using 2 shade-matching techniques. The first technique was conventional visual matching using 3 shade guide systems, and the second was an instrument-based Color-matching technique using a new spectrophotometric system. Color difference (ΔE) values between the contralateral natural Tooth and each of the 2 crowns were calculated in the cervical, middle, and incisal regions. The ΔE values were compared using a Student's t test (α=.05). Three calibrated examiners evaluated the Color match by ranking it from 1 to 10 (10 = perfect match; 1=no match; ≤8, accepted; ≥7, rejected). McNemar's test was used to calculate the odds ratio of accepting restorations fabricated using a spectrophotometric system to conventional methods. Results Results revealed that the mean ΔE values of crowns matched with the spectrophotometer were significantly lower than those using a conventional technique ( P P Conclusions In this clinical study, crowns fabricated using a dedicated spectrophotometer had a significantly better Color match and a lower rate of rejection due to shade mismatch compared to crowns fabricated with a conventional shade-matching method. (J Prosthet Dent 2008;99:361-368)
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reproducibility of Tooth Color gradation using a computer Color matching technique applied to ceramic restorations
Journal of Prosthetic Dentistry, 2005Co-Authors: Shigemi Ishikawanagai, Kanji Ishibashi, Osamu Tsuruta, Hanspeter WeberAbstract: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 × 3 mm wide). The Color differences, ΔE, ΔL ∗ , Δa ∗ , and Δb ∗ , were calculated. The Color difference ΔE values were analyzed by a repeated measures analysis of variance ( P Results The mean Color difference (ΔE) 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 ΔE values among target-shade tabs ( P P P 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.
Stephen F. Rosenstiel - One of the best experts on this subject based on the ideXlab platform.
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evaluating Tooth Color change from carbamide peroxide gel
Journal of the American Dental Association, 1993Co-Authors: Anthony G. Gegauff, Stephen F. Rosenstiel, Kristen J Langhout, William M. JohnstonAbstract:A double-blind experiment assessed the efficacy, longevity and safety of a Tooth whitener in young adults. Significant Color changes occurred after active treatment but were substantially reversed after one week. No permanent changes were found in either pulpal or gingival health.
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Duration of Tooth Color change after bleaching.
The Journal of the American Dental Association, 1991Co-Authors: Stephen F. Rosenstiel, Anthony G. Gegauff, William M. JohnstonAbstract:Tooth Color change was monitored after a single, in-office bleaching technique using a Colorimeter. Twenty young adults participated in the double-blind study at The Ohio State University College of Dentistry. Half of the participants had their maxillary anterior teeth bleached and half were controls. By one month, the large initial Color change was considerably reversed and only noticed by one subject. After six months, the effect of bleaching was small, but still measurable.
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in vitro Tooth Color change with repeated bleaching
Quintessence International, 1991Co-Authors: Stephen F. Rosenstiel, Anthony G. Gegauff, R J Mccafferty, William M. JohnstonAbstract:The interest of patients in vital Tooth bleaching has created a demand for treatment. However, few objective data are available to help determine the number of bleaching appointments necessary and the lightening that can be expected. The purpose of this study was to measure Color changes in bleached extracted teeth and compare these to control groups. Group A was etched and bleached with 35% stabilized hydrogen peroxide. Group B was treated the same as group A, but the bleaching solution was replaced with distilled water. Group C was not treated, but was stored in water. Mean Color difference after one treatment was 3.33 for group A, 1.67 for group B, and 0.48 for group C. After six treatments, the overall Color difference was 3.82, 2.41, and 1.38 for groups A, B, and C, respectively (P less than .01). Color changes beyond those found after the first treatment were small, suggesting that there was little benefit in repeated bleachings under the conditions of this study.