Digital evaluation of dental bleaching using a new methodology: an in vivo study.

Objective: The objective of the present study was to assess the progress and efficiency of at-home bleaching protocols with 10% carbamide peroxide using a new methodology based on dental photography.

Materials and methods: A 4-week overnight at-home bleaching protocol using whitening trays and 10% carbamide peroxide was performed on 52 patients. The tooth color was analyzed using standardized photographs taken every week for 4 weeks and at 4 months posttreatment. The values of the color evolution (ΔE00), L*, a*, and b* were also measured and used to assess the evolution of the chroma, luminosity, and hue using the CIEDE2000 formula. The statistical analyses were conducted at a significance level of P < 0.05 by means of a repeated measures analysis of variance (ANOVA).

Results: The tooth color changed the most, and thus the highest ΔE00 was observed, after the first week of treatment. The color continued to change but to a lesser degree during the following weeks. After 4 weeks, the treatment proved to be very effective. Four months after the end of treatment, a color relapse was observed, though it was hardly perceptible to the human eye. The luminosity (L') changed significantly between the beginning and the end of treatment, affecting the maxilla to a greater extent. The chroma evolution showed a high variance and a low relapse for both jaws. The hue was not affected significantly during the treatment and the stabilization.

Conclusions: Within the limitations of the present study, the authors were able to assess the progress and efficiency of at-home bleaching with 10% carbamide peroxide in terms of chroma, luminosity, and hue using a new methodology based on dental photography.

Clinical significance: This new method is effective and enables a reliable analysis of the evolution of a dental bleaching treatment, turning dental photo-graphy into an even more powerful tool for analysis and communication. It can also be used as a proof-of-concept, paving the way for further research on objective monitoring and evaluation of dental treatments using dental photography.