News Release

A new method is developed for predicting shade improvement after teeth bleaching

Peer-Reviewed Publication

University of Granada

This release is available in Spanish.

Researchers at the University of Granada have developed a new method for predicting the precise shade that a bleaching treatment will bring about for a patient's teeth. What is innovative about this method is that it allows researchers to successfully predict the outcome of a bleaching treatment, which will have a significant impact on such treatments, which are becoming more frequent.

At present, dental offices routinely employ carbomide peroxide bleaching agents for tooth discoloration. As bleaching treatments have soft side effects –all of them temporary and mild– and are relatively cost-effective, they have become very popular.

While bleaching treatments have been long applied, one of its main problems has been the inability to predict the outcome of the process. This means that, so far, dentists have been unable to predict the results for patients' teeth. This means that dental physicians could not inform their patients on the shade improvement that the treatment would bring about, which was a limitation to the therapy.

The study was conducted by Janiley Santana Díaz, at the Department of Stomatology of the University of Granada and was coordinated by professors Rosa Mª Pulgar Encinas, Mª Del Mar Pérez Gómez and Luis Javier Herrera Maldonado. Using a fuzzy rule system, scientists had a first approach to the shade improvement that teeth can get after undergoing a 20% carbamide peroxide treatment (Opalescence® PF 20%, Ultradent) two hours a day for two weeks.


For the purpose of this study, authors took a sample of 53 subjects that subsequently underwent a teeth bleaching treatment. Before the bleaching treatment, participants answered a questionnaire on their eating habits so that scientists analyzed whether such habits had any impact on the prediction models. The researchers found that eating habits are not relevant to such models, so these factors where not considered in the study.

To illustrate the shade change expected after the teeth bleaching treatment, the University of Granada researchers designed a fuzzy system that allows to associate these instrumental measures to the commercial shade guides typically used at dental offices to identify the before-and-after tooth color.

Such association allows to establish a series of objective guidelines that, once the before-tooth color is identified with the closest shade of the guide, will allow both dentist and patient to predict the color that the teeth will get after the treatment.

All in all, researchers warn that, in the long term and given the limitation of any clinical trial, a wider range of patients and initial tooth colors would be required to obtain a more precise fuzzy system.



National Communications:

L.J. Herrera, H. Pomares, I. Rojas, J. Santana, R. Pulgar, R. Ghinea, M.M. Pérez. Sistemas Neuro-Difusos para el Modelado de la Evolución del Color. Modelado de un Proceso de Blanqueamiento Dental. ESTYLF´2010, February 3-5, 2010. Accepted for publication.

International Communications:

J. Santana-Díaz, J. López-García, L.J. Herrera-Maldonado, M.M. Pérez-Gómez, R. Pulgar-Encinas. Prediction of color change after tooth bleaching using color CIELAB parameters and linear models. CONSEURO 2009, March 2009 Seville, Clinical Oral Investigations, vol. 13, No 1, pp. 97 (49-118).

L.J. Herrera, M.M. Pérez, J. Santana, R. Pulgar, J. González, H. Pomares, I. Rojas. A Data Mining Approach Based on a Local-Global Fuzzy Modelling for Prediction of Color Change after Tooth Bleaching using Vita Classical Shades. 2009 Ninth International Conference on Intelligent Systems Design and Applications, December 2009 Pisa, Italy, pp. 1268-1273.

Published Article:

Herrera LJ, Pulgar R, Santana J, Cardona JC, Guillén A, Rojas I, Pérez MM. Prediction of Color Change after Tooth Bleaching using Fuzzy Logic for Vita Classical Shades Identification. Article approved for publication in the journal Applied Optics, February 2010, vol. 49 No 4.

Contact: Janiley Santana Díaz. Department of Stomatology of the University of Granada. Phone Number: +34 958 248 983. E-Mail Address:

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