Proposed shade guide for human facial skin and lip: a pilot study.

STATEMENT OF PROBLEM: Currently, no commercially available facial shade guide exists in the United States for the fabrication of facial prostheses. PURPOSE: The purpose of this study was to measure facial skin and lip color in a human population sample stratified by age, gender, and race. Clustering analysis was used to determine optimal color coordinates for a proposed facial shade guide. MATERIAL AND METHODS: Participants (n=119) were recruited from 4 racial/ethnic groups, 5 age groups, and both genders. Reflectance measurements of participants' noses and lower lips were made by using a spectroradiometer and xenon arc lamp with a 45/0 optical configuration. Repeated measures ANOVA (α=.05), to identify skin and lip color differences, resulting from race, age, gender, and location, and a hierarchical clustering analysis, to identify clusters of skin colors) were used. RESULTS: Significant contributors to L*a*b* facial color were race and facial location (P<.01). b* affected all factors (P<.05). Age affected only b* (P<.001), while gender affected only L* (P<.05) and b* (P<.05). Analyses identified 5 clusters of skin color. CONCLUSIONS: The study showed that skin color caused by age and gender primarily occurred within the yellow-blue axis. A significant lightness difference between gender groups was also found. Clustering analysis identified 5 distinct skin shade tabs.

Incisal translucency of vital natural unrestored teeth: a clinical study.

INTRODUCTION: Understanding the distribution of incisal translucency will provide clinicians a guide to use this knowledge to improve the esthetic replication of anterior restorations. The aim of this study is to investigate the distribution of incisal translucency of unrestored vital natural maxillary central, lateral, and canine vital teeth from a stratified population in different age, gender, and race. MATERIALS AND METHODS: A total of 120 subjects were recruited for this study. Six subjects with equal gender balance from four racial/ethnic groups (White, Black, Asian, and others) were recruited from each of the following age groups: 18 to 29 years, 30 to 39 years, 40 to 49 years, 50 to 59 years, and 60 to 85 years. Potential subjects were clinically screened to determine if three specific anterior teeth (maxillary central incisor, lateral incisor, and canine) were non-restored, natural permanent teeth free from external staining or bleaching. A digital imaging and shade analysis device was used to measure tooth translucency. RESULTS: Statistically significant interaction (p < 0.001) was found for the groups. The interaction between race and gender was not statistically significant (p = 0.485). However, the interaction between race and age (p = 0.03), age and gender (p = 0.015), and among age, race, and gender (p < 0.001) was found statistically significant according to the analysis of variance test results. The interaction between race and gender was not statistically significant (p = 0.485).

Reliability and accuracy of four dental shade-matching devices.

STATEMENT OF PROBLEM: There are several electronic shade-matching instruments available for clinical use, but the reliability and accuracy of these instruments have not been thoroughly investigated. PURPOSE: The purpose of this in vitro study was to evaluate the reliability and accuracy of 4 dental shade-matching instruments in a standardized environment. MATERIAL AND METHODS: Four shade-matching devices were tested: SpectroShade, ShadeVision, VITA Easyshade, and ShadeScan. Color measurements were made of 3 commercial shade guides (Vitapan Classical, Vitapan 3D-Master, and Chromascop). Shade tabs were placed in the middle of a gingival matrix (Shofu GUMY) with shade tabs of the same nominal shade from additional shade guides placed on both sides. Measurements were made of the central region of the shade tab positioned inside a black box. For the reliability assessment, each shade tab from each of the 3 shade guide types was measured 10 times. For the accuracy assessment, each shade tab from 10 guides of each of the 3 types evaluated was measured once. Differences in reliability and accuracy were evaluated using the Standard Normal z test (2 sided) (alpha=.05) with Bonferroni correction. RESULTS: Reliability of devices was as follows: ShadeVision, 99.0%; SpectroShade, 96.9%; VITA Easyshade, 96.4%; and ShadeScan, 87.4%. A significant difference in reliability was found between ShadeVision and ShadeScan (P=.008). All other comparisons showed similar reliability. Accuracy of devices was as follows: VITA Easyshade, 92.6%; ShadeVision, 84.8%; SpectroShade, 80.2%; and ShadeScan, 66.8%. Significant differences in accuracy were found between all device pairs (P<.001) for all comparisons except for SpectroShade versus ShadeVision (P=.033). CONCLUSIONS: Most devices had similar high reliability (over 96%), indicating predictable shade values from repeated measurements. However, there was more variability in accuracy among devices (67-93%), and differences in accuracy were seen with most device comparisons.

In vitro model to evaluate reliability and accuracy of a dental shade-matching instrument.

STATEMENT OF PROBLEM: There are several electronic shade-matching instruments available for clinical use; unfortunately, there are limited acceptable in vitro models to evaluate their reliability and accuracy. PURPOSE: The purpose of this in vitro study was to evaluate the reliability and accuracy of a dental clinical shade-matching instrument. MATERIAL AND METHODS: Using the shade-matching instrument (ShadeScan), color measurements were made of 3 commercial shade guides (VITA Classical, VITA 3D-Master, and Chromascop). Shade tabs were selected and placed in the middle of a gingival matrix (Shofu Gummy), with tabs of the same nominal shade from additional shade guides placed on both sides. Measurements were made of the central region of the shade tab inside a black box. For the reliability assessment, each shade tab from each of the 3 shade guide types was measured 10 times. For the accuracy assessment, each shade tab from 10 guides of each of the 3 types evaluated was measured once. Reliability, accuracy, and 95% confidence intervals were calculated for each shade tab. Differences were determined by 1-way ANOVA followed by the Bonferroni multiple comparison procedure. RESULTS: Reliability of ShadeScan was as follows: VITA Classical = 95.0%, VITA 3D-Master = 91.2%, and Chromascop = 76.5%. Accuracy of ShadeScan was as follows: VITA Classical = 65.0%, VITA 3D-Master = 54.2%, Chromascop = 84.5%. CONCLUSIONS: This in vitro study showed a varying degree of reliability and accuracy for ShadeScan, depending on the type of shade guide system used.