Discoloration of stretched colored elastomeric modules : An in vivo study.

Background: As the demands on esthetic orthodontic devices continue to increase, discoloration of colored elastomeric modules is still a concern for patients and orthodontics. Thus, we performed an in vivo study evaluating discoloration of stretched colored elastomeric modules (i.e., white, gray, and pink).

Materials and methods: In all, 90 elastomeric modules of three different colors (white, gray and pink; 30 elastics from each color) were placed around brackets. The elastomeric modules were distributed and arranged randomly in the patients' four dental quadrants, and were removed after 1, 2, and 4 weeks. Color measurements were made before and after insertion into each patient's mouth. Digital images were taken with the camera of a mobile phone (iPhone X, Cupertino, CA, USA), and the variations in color were characterized using the Commission Internationale de l'Eclairage (CIE) color space system (L*a*b*) offered by Photoshop (Adobe, San Jose, CA, USA). Analysis of variance (ANOVA) and least significant difference (LSD) tests were used for statistical analyses.

Results: The white elastomeric modules were most prone to discoloration, followed by the pink and then finally by the gray colored modules. The amount of discoloration resulting from a random diet practiced by the patients increased gradually (but was not significant) for all elastomeric modules studied and reach a peak after 2 weeks for the white and gray elastomeric modules, while discoloration of the pink elastomeric modules plateaued after 1 week.

Conclusion: Colored elastomeric modules (e.g., white, gray, and pink) discolor to variable degrees over time. Thus, patients should be advised that the consumption of food and drinks may result in discoloration of the elastomeric modules.