Patients can use custom trays to whiten teeth at home, or to touch up teeth that were whitened by other treatments.

They can be, but it's going to take a lot more time for them to whiten. At-home solutions are typically not as strong and powerful as in-office materials. An at-home product, however, is a good way to maintain white teeth after doing an in-office procedure. Patients need to have a dental exam first to determine the ideology of their discoloration and whether a tooth whitening product can treat it.