Original ArticlesColor and translucency of in vivo natural central incisors☆,☆☆
Section snippets
Material and methods
Eighty-seven Japanese subjects (42 men and 45 women) were randomly selected for this study. They ranged in age from 13 to 84 years old and were classified into 6 age groups for each sex: under 19, 20 to 29, 30 to 39, 40 to 49, 50 to 59, and more than 60 years of age (Table I).
Age group (y) Male Female Total Under 19 9 (13.9) 7 (18.9) 16 (16.1) 20 to 29 9 (26.7) 8 (22.9) 17 (24.9) 30 to 39 8 (35.0) 10 (35.1) 18 (35.1) 40 to 49 7 (44.3) 7 (47.4) 14 (45.9) 50 to 59 6 (54.2) 4
Results
Table II shows the correlation coefficient between L*, a*, b*, TP, and age groups at each site. The simple linear regression analyses for L* revealed a significant negative correlation with age at the center, center-cervical, and cervical sites, but no such correlation was found at the incisal and incisal-center sites. For a*, no significant correlation was observed with age, except at the incisal site, where a significant positive correlation was found. For b*, a significant positive
Discussion
In this study, lightness (L*) at the center, center-cervical, and cervical sites decreased linearly with age (Table II), which is consistent with the findings of Goodkind et al.19 It is speculated that natural teeth darken after the age of approximately 35 years by the formation of secondary dentine.19 However, in our study, the decrease in lightness was not found at 2 neighboring incisal sites. This can be explained by the effects of the black cloth as a background through the translucent
Conclusion
The color and translucency of individual teeth and shade tabs were measured using a novel color computer system. Within the limits of this study, the following conclusions were drawn:
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Natural tooth color showed a significant decrease in lightness at the center to cervical site and increase in yellowness at all 5 sites with advancing age. The color of natural teeth also showed an increase in redness at the incisal site and a decrease in translucency in the region near the incisal site with age,
Acknowledgements
With grateful thanks to Dr M. Analoui (Indiana University, Indiana), and Mr R. Gilmore (AstraZeneca, UK) for their kind assistance and syntax for valuable comments on the manuscript.
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2021, Annals of AnatomyCitation Excerpt :A positive b* value indicates the yellowness of an object; its negative progression indicates increasing blueness. After a bleaching treatment, it is expected that the b* value decreases – that is, the measured object will progress towards blue (Hasegawa et al., 2000). Even if the ΔE00 value (the difference between 2 measurements) has increased by a degree, it is not acceptable clinically difference (for visibility).
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