Quantitative clinical evaluation of esthetic properties of incisors

Objective. To match perfectly the optical properties of natural teeth, a scientific approach is needed by using digital technology that excludes bias to quantitatively characterize the optical properties of populations' teeth. The aim of this article is to present a method for a detailed clinical quantification of optical properties of front teeth. Methods. A novel spectrophotometric approach was developed and applied on a preliminary group of subjects quantifying L* (luminosity) a* (quantity of green-red) and b* (quantity of blue-yellow) of enamel and enamel-dentin complex against black and white background. Based on these in vivo data, CR (opacity) and opalescence (the ability to reflect blue wavelength when white light stroke the object perpendicularly) were also calculated. Results. The mean values of L* of the enamel-dentin complex against black and white background were 79.6 and 75.4, respectively The mean values of a* were 2.5 against black and 0.8 against white background, respectively The mean values of b* were 17.4 against black and 13.0 against white background, respectively The mean contrast ratio was 86.7%. Opalescence value was 4.8. The mean values of L* of enamel against black and white background were 79.0 and 64.2, respectively. The mean values of a* were 2.1 against black and -0.3 against white background, respectively The mean values of b* were 15.2 against black and 8.7 against white background, respectively The mean contrast ratio was 60.5%. Opalescence value was 7.4. Significance. The described methodology, applied on a larger group of subjects, may serve as a database for a more exact characterization of optical properties of natural enamel and dentin. (C) 2007 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.