How White Can We Go?
With the growing popularity of vital bleaching, new challenges arise for the dental team due to the fact that many patients are whitening their teeth to shades brighter and whiter than conventional shade guides cover. Therefore, bleaching presents a number of variables that can make accurate shade matching somewhat of a moving target.
Because bleaching does not occur in a linear fashion, the amount of color can change. The initial application is usually greater than in the subsequent ones and varies from patient to patient.
Patient Behavior:
If the patient continues bleaching after the final shade has been taken, teeth will continue to lighten and the bleached teeth will not match the restoration.
Etiology of the Discoloration:
Stains caused by extrinsic organic pigments such as coffee, chocolate, red wine or tobacco are more readily bleached out than intrinsic discoloration such as tetracycline staining or flourosis.
Rebound Effect:
Bleached teeth are usually brighter during the treatment and take up to three weeks to “rebound” to a more stable shade. This phenomenon is most pronounced in the first four to six days.
The Relapse Factor:
In general, bleached teeth tend to slowly relapse toward their pre-whitened state, but this can be controlled by occasional re-treatments. However, if the patient continues tooth staining diets or habits, this relapse factor is accelerated while the shade of the restoration remains unchanged.
So What Do We Do?
Final shade should be taken at lease five days (and at best-three weeks) after the last bleaching treatment, especially for single anteriors.
The patient needs to realize the ramifications of continuous bleaching. The rebound and relapse factor must be discussed with the patient.
To avoid remakes, the patient must sign a custom shade form approving the shade selection and acknowledge that he or she has been informed about the effects of future bleaching. |