Color fading of the blue compliance indicator encapsulated in removable clear Invisalign Teen® aligners

To evaluate the color fading in aqueous solutions of the blue dot wear-compliance indicators of the Invisalign Teen® System outside the oral cavity.

The compliance indicators in the Invisalign Teen aligners were tested for color resistance in various aqueous models with no saliva involved.

Color fading was observed as a function of time, pH, and temperature while compliance indicators were stored in drinking water or sour soft drinks and in conjunction with the use of cleaning tablets and a dishwasher. The findings of color fading were consistent with the color changes observed when the aligners were being worn by patients. Color fading, notably as observed in connection with acidic soft drinks and cleaning techniques, introduces uncertainty into the assessment of actual patient compliance, as reflected by the fading colors of compliance indicators.

Compliance indicators are not immune to simple intentional or unintentional manipulations. Therefore, they can best show an estimate of wear time but cannot be recommended as objective wear-time indicators.