A great alternative to tooth whitening treatments involving strips or a whitening pen is the use of whitening toothpastes. They use the same types of chemicals that whiten teeth, but in much smaller doses, thus minimizing possible side effects of daily use. Colgate has a number of these, the newest being the Optic White series. These toothpastes are supposed to guarantee whiter teeth after just a week of regular use.
Whitening toothpastes do work but the process is gradual, so you will not see a sudden change in your smile but your teeth will become two shades lighter over time. The upside is that this whiter smile will stay, as you will be reapplying the whitening material twice a day.