The first couple of days after tooth whitening are the most critical. After whitening the pores or dentinal tubules are open and most susceptible to staining. I tell my patients to wait at least 36-48 hours to consume food or beverages that may stain teeth; those include anything that may stain a white t-shirt. All systems require maintenance, even at-home trays. Consuming beverages that may stain teeth with a straw helps to keep your teeth sparkling!
For the best result, avoid foods that have a lot of color (coffee, tea, mustard, cranberry juice, red wine) for several days until the open pores in the tooth have closed over. Also, please note that led light treatments have to be spaced at a minimum of 6 months. During this time you have to use the after care kit to maintain the result. Otherwise, you loose the result in no more than three weeks.