Abstract
Aim: To evaluate the influence of the parameters L* a* b* on the variation of the color of bovine tooth enamel submitted to artificial darkening, after simulated brushing, with whitening toothpastes containing blue covarine. Methods: To undertake this study in vitro, 60 specimens (SP) were divided into 6 groups (n=10): control group (CGwater) and 5 test groups (GT1-Colgate Total 12, GT2-Oral-B 3D White Perfection, GT3- Colgate Luminous Instant White, GT4-CloseUp White Diamond Attraction, GT5-Sorriso Xtreme White). The specimens were darkened with coffee and submitted to simulated brushing for 6, 12, and 24 months. The alteration in the color was evaluated using CIELAB parameters and the ΔL, Δa, Δb and ΔE were calculated. The data was analyzed through generalized linear models using the R program and considering a level of significance of 5%. Results: The parameters L*, a* and the ΔL, Δa obtained better results in the test group than in the control group. There were no statistical differences between CG and the test groups for the evaluation of the b* parameter. In the evaluation of the Δb, the GT3 differed statistically from the CG. In relation to the ΔE, all the group tests showed a variation in color statistically greater than that of the CG and the GT4 showed the greatest variation, not differing from the GT3 during the periods studied. Conclusion: The mechanical and optical whitening agents positively influenced the values L*a* and b*, as well as in its variations and in the ΔE. It is important to emphasize, however, that to analyze tooth whitening it is necessary to evaluate their parameters together.
Highlights
Color is a perceptual phenomenon and, for that reason, subjective which depends on the observer, lights and object
The literature relative to the evaluation of color through the individual parameters of CIELAB demonstrates that the perception of dental whitening occurs with the increase of L*, decrease of b* and to a lesser degree the decrease in the a* parameter[1,8]
The whitening agents can be incorporated into toothpastes to be used for daily oral hygiene
Summary
Color is a perceptual phenomenon and, for that reason, subjective which depends on the observer, lights and object. With the purpose of establishing colorimetric criteria to quantify and describe this human perception, the Comission Internationale de l’Eclairage (CIE) defined color in three dimensions: luminosity or value, which is the luminosity relative to the color and encompasses the quantity of gray; the shade, the real color of the object such as green, red, blue and yellow; and chroma, which is the concentration or intensity of the shade[1]. CIELAB is defined numerically by three measurements: Luminosity (L*) which varies between 0 to 100; the a* coordinate, the red-green axis, which varies between -80 to +80, and the b* coordinate, the yellow-blue axis, which varies between -80 to +802. Positive values of b* indicate yellow tones and negative b* values indicate blue tones. Negative values of a* indicate green tones, whereas positive values indicate red tones. The higher the value of L* and the lower the values of a* and b*, the tooth will be lighter and whiter[1,3]
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