In vivo quantitative evaluation of tooth color with hand-held colorimeter and custom template

In-vivo repeatability of three intra-oral spectrophotometers

OBJECTIVE

The objective was to assess the repeatability of three spectrophotometers, based on the CIELCh factors and shadeguide reference measurements.

MATERIALS AND METHODS

Color analysis was performed using three devices: Rayplicker, Easyshade 4, and Easyshade V. Five repeated measures were performed by the same operator, on the right central maxillary incisor of 30 patients. The CIELCh factors were retrieved and the intra-class correlation was calculated. The Vita Classical and Vita 3D Master shadeguides were used to evaluate the respective Fleiss' Kappa factors.

RESULTS

Rayplicker and Easyshade V demonstrated strong intra-class correlation based on the CIELCh factors: 0.98, 0.99, and 0.91 for Rayplicker, and 0.95, 0.99, and 0.93 for Easyshade V, for the L*, C*, and h* parameters, respectively. Regarding the repeatability of the shadeguide data, while Easyshade 4 had the best repeatability when using the Vita Classical as a reference, Rayplicker and Easyshade V showed better repeatability when using the Vita 3D Master.

CONCLUSION

These findings suggest that both Rayplicker and Easyshade V are reliable devices for measuring CIELCh parameters. In terms of shadeguide references, the reliability of spectrophotometers is generally lower compared to the CIELCh measurements.

CLINICAL SIGNIFICANCE

Given their good repeatability, both the Rayplicker and the Easyshade V spectrophotometers are reliable tools for prosthetic dental practices.

A Clinical Evaluation of Difference in Shades among Maxillary Central Incisor, Canine, and First Molar in a Young Age-group Using Digital Spectrophotometer: An In Vivo Study

AIM

The aim of this study was to evaluate and compare the most common shades of maxillary central incisor, canine and first molar and to confirm the shade difference between maxillary central incisor and canine in a young population of 18-25 years.

MATERIALS AND METHODS

The shade of the maxillary central incisor, canine, and first molar of 100 study participants in a young population between 18 and 25 years were measured by digital spectrophotometer (VITA Easyshade). The shade of each tooth was assessed thrice with a digital spectrophotometer at the center of the tooth. Statistical analysis was performed; Chi-squared test was applied to assess the difference in shades.

RESULTS

For the age-group of 18-25 years, the most common shade of maxillary central incisor is A1 and for canine and first molar the most common shade is B3. A highly statistically significant difference (p < 0.001) was observed between teeth, suggesting a definitive shade difference between teeth.

CONCLUSION

A definitive shade difference exists between the maxillary central incisor and the canine, with the canine being darker in shade than the central incisor. This result can be implied clinically while restoring maxillary anterior teeth to yield a better esthetic outcome.

CLINICAL SIGNIFICANCE

This study reveals that there is a definitive shade difference between the Anterior teeth which should be considered while smile designing to replicate the natural appearance in a patient. Using a digital spectrometer makes the process of shade selection objective thereby eliminating any subjective variations.

How reliable and accurate is the shade determination of premolars by spectrophotometry?

OBJECTIVES

To evaluate the reliability and accuracy of spectrophotometric shade determination of premolars and to compare the results with those for incisors.

MATERIAL AND METHODS

Fifty-seven participants with natural maxillary incisors and premolars were recruited to investigate the research question. The colour of test teeth (incisors, n = 210; premolars, n = 192) was measured by use of the Vita Easyshade Advance (ES-A) and Vita Easyshade V (ES-V). Accuracy was evaluated by rating the shade tab matches recommended by the devices (scale, 1 = excellent match to 3 = mismatch). Inter-device reliability between the ES-A and ES-V for measurement of incisors and premolars was evaluated using intra-class correlation coefficients (ICC). The ratings for the accuracy of the devices were analysed using descriptive and bivariate statistics. A linear regression model was used to evaluate possible independent influencing confounders on the shade match.

RESULTS

Inter-device agreement of the ES-A and ES-V for measurement of incisors and premolars was excellent for all colour components (ICC > 0.9). The accuracy of both devices was acceptable to excellent for incisors and premolars, although the ES-V was more accurate than the ES-A (p < 0.001). No significant difference in accuracy was detected between premolars and incisors (p = 0.182). The linear regression model confirmed the bivariate testing.

CONCLUSIONS

The reliability and accuracy of spectrophotometric shade determination seem comparable for incisors and premolars. The recently introduced ES-V seems more accurate than its predecessor model. Further studies are needed to validate the results of this study.

Colorimetric distribution of human attached gingiva and alveolar mucosa

STATEMENT OF PROBLEM

Few studies have investigated the colorimetric distribution of gingival color, including the posterior area and alveolar mucosa.

PURPOSE

The purpose of this in vivo study was to investigate the distribution of colorimetric values in different areas of gingiva and to determine its relationship to colorimetric findings of the tooth and skin in a young Korean population.

MATERIAL AND METHODS

Participants included 40 periodontally healthy adults (22 men and 18 women) 25 to 36 years of age. Commission Internationale de l'Eclairage values (CIELab: L* lightness, a* green-red, and b* blue-yellow) were measured using a colorimeter at a total of 23 sites for each participant, including attached gingiva (AG) and alveolar mucosa (AM) in the maxillary and mandibular and incisor and molar regions, maxillary central incisor, and skin points of the glabella, cheek, and inner upper arm.

RESULTS

AG showed higher L* and lower a* values than AM. AG demonstrated higher L* and lower a* values in the maxillary region than in the mandibular region and higher b* values in the incisor region than in the molar region. AM revealed higher L* and lower a* and b* values in the incisor region than in the molar region. Positive significant correlations were found for L* between the skin area and AM and for b* between the skin area and AG.

CONCLUSIONS

The colorimetric values of AG and AM differ according to the area, possibly as a result of differences in anatomic and histologic distribution that influence optical properties.

Spectrophotometric color evaluation of permanent incisors, canines and molars. A cross-sectional clinical study

Background and aims

An accurate color reproduction represents the final validation level of an esthetic anterior or posterior restoration. The aim of this study was to evaluate the color of permanent maxillary incisors, canines and molars, using a clinical spectrophotometer.

Methods

The Vita Easyshade Advance 4.0^® intraoral spectrophotometer was used by one clinician to determine the color of 369 permanent maxillary incisors, canines and molars. The best matches to Vitapan Classical^® and 3D-Master^® shade guides were recorded. A one-way analysis of variance and Kruskal-Wallis test were used to compare L*, a*, b*, c* and h* color coordinates among the 3 types of teeth. Differences between the mean values of all color coordinates were evaluated by use of Bonferroni corrections. Color difference (ΔE*) between incisors, canines and molars was calculated from ΔL*, Δa* and Δb* data and the results were compared to ΔE*=3.3 acceptability threshold.

Results

Except for Δa* and Δh* between canines and molars, statistically significant differences among the mean differences of all color coordinates were found when the 3 types of teeth were compared by pairs. The most frequently measured shades were A1 (48.4%), respectively 1M1 (31.5%) for incisors, B3 (36.6%), respectively 2M3 (39.8%) for canines and B3 (44.7%), respectively 2M3 (52%) for molars. Incisors had the highest lightness values, followed by canines and molars. Molars were the most chromatic with the highest a* and b* values.

Conclusions

Despite the limitations of this study, color differences among incisors, canines and molars were found to be statistically significant, above the clinical acceptability threshold established. In conclusion, successful esthetic restorations of permanent teeth of the same patient need an individual color assessment and reproduction of every type of tooth.

Clinical efficacy of a bleaching enzyme-based toothpaste. A double-blind controlled clinical trial

OBJECTIVES

To assess the efficacy of a bleaching enzyme-based toothpaste.

MATERIAL AND METHODS

A randomized clinical trial was carried out, comprising 48 participants with teeth exhibiting color A3 or higher according to the Vita Classical guide. One-half of the sample received the bleaching enzyme-based toothpaste (White Kin(®)), while the other received placebo toothpaste. Both products were supplied in identical containers and had the same composition except for the active components. The teeth color was measured with a spectrophotometer. The patients were instructed to brush their teeth three times a day during 3 min with the assigned product, during 12 weeks. The color measurements were repeated after 3, 6, 9 and 12 weeks of treatment. Color variation was based on the CIE L*a*b* coordinates, ΔE and the EW index. The relationship of these variables at different observation times were performed using a generalized estimating equations model, which evaluated the effect of treatment, time and interaction.

RESULTS

The patients using the bleaching enzyme-based toothpaste showed an increase in lightness (80.14 -treatment- versus 79.25 -control group-) and a reduction in component b*. ΔE was found higher in the treatment group (p=0.064), close to statistical significance.

CONCLUSIONS

The bleaching enzyme-based toothpaste could be potentially efficient in the modification in tooth color progressing from the third to ninth week of treatment, tending to stabilize after the ninth week.

CLINICAL RELEVANCE

A very low carbamide peroxide concentration, with the incorporation of lactoperoxidase, tooth paste, tends to offer clinically satisfactory results, in terms of modifications in tooth color, nevertheless no significant differences were founded when compared to the control group, with an oral hygiene controlled along the study.

Prediction of color change after tooth bleaching using fuzzy logic for Vita Classical shades identification

Tooth bleaching is becoming increasingly popular among patients and dentists since it is a relatively noninvasive approach for whitening and lightening teeth. Instruments and visual assessment with respect to commercial shade guides are currently used to evaluate tooth color. However, the association between these procedures is imprecise and the degree of color change after tooth bleaching is known to vary substantially between studies; there are currently no objective guidelines to predict the effectiveness of a tooth-bleaching treatment. We propose a new methodology based on fuzzy logic as a natural means of representing the imprecision present when modeling the color change produced by a tooth-bleaching treatment on the basis of a tooth's initial chromatic values. This system has the advantage of producing a set of interpretable fuzzy rules that can subsequently be used by scientists and dental practitioners. The fuzzy system obtained has the special characteristic whereby the rule antecedents correspond to prebleaching shades of the well-known Vita commercial shade guide. Additionally, the rule consequents directly correspond with the expected CIELAB postbleaching values for each Vita shade, thanks to a modification of the system's inference structure. Finally, the values of these postbleaching CIELAB coordinates have been associated with Vita shades by evaluating their respective membership functions, thereby approximating which posttreatment Vita shades are to be expected for each prebleaching shade.

The prevalence of tooth discolouration and the self-satisfaction with tooth colour in a Chinese urban population

OBJECTIVES

To determine the prevalence of tooth discolouration, self-satisfaction with tooth colour, and correlation with socio-demographic-behavioural factors in adults and teenagers in Chengdu, China.

DESIGN

A cross-sectional survey.

PARTICIPANTS

405 Chinese urban adults and teenagers from a multistage random probability sample.

METHODS

Tooth colour was measured on the maxillary central incisors using a colorimeter. Tooth discolouration was determined according to the discolouration level figure and evaluation criteria. Self-satisfaction with tooth colour was assessed on a five-point qualitative scale. Data were coded and analyzed using SPSS software.

RESULTS

The mean values for L*, a* and b* were 70.67 (s.d. 1.91), 4.29 (s.d. 2.05) and 17.51 (s.d. 4.13), respectively. Age and sex were the most important factors associated with tooth colour (P < 0.05). About half of the study population (48.9%) suffered from some tooth discolouration, and 52.6% were dissatisfied with their tooth colour. Education and smoking were significant factors affecting self-satisfaction with tooth colour (P < 0.05).

CONCLUSIONS

Tooth discolouration is common among the Chinese, and many Chinese are dissatisfied with their tooth colour. Self-satisfaction with tooth colour decreased with increasing severity of discolouration. Further research is needed to determine types of tooth discolouration among broader regions in China.