Always dentists and/or the manufacturers of professional teeth whitening products advertise their systems as "one visit, one hour teeth whitening." We will agree that one hour of professional in-office teeth bleaching treatment should be expected to provide a color change for a person's teeth.The other side of this discussion is to state that it has been reported in dental literature that the average number of professional teeth whitening treatments needed to "make patients happy" is three. While whitening results were seen after a single visit, it typically took between two to six in-office bleaching appointments to reach "maximum whiteness." When determining if professional teeth bleaching treatments are the best whitening option for you, you should take into consideration that more than one whitening treatment might be needed. These extra appointments will require further time commitment and cost on your part.