Hi,I would say it depends on the kind of whitening system you are using and what your habits are. If you are looking to whiten dramatically, or if you have sensitive teeth, I would suggest consulting your dentist and looking into an in-office whitening option. Often times, these options (like Zoom, or Kor), have desensitizing agents that will help with some of the post-bleaching sensitivity you may experience, whereas over-the counter whitening strips are not as effective and are known to cause more severe sensitivity.Regarding if it is better to do it in the morning or at night- if you are in the habit of drinking coffee or tea in the morning, whitening right before that can actually make your teeth darker instead of whiter. This is because your enamel rods open up during the bleaching process and your teeth are much more susceptible to staining if you drink or eat darkly colored items. Same goes for if you like drinking wine at night. I would actually suggest staying away from any food or drinks that are harshly colored (dark chocolate, coffee, tea, sodas, wine, etc) while you whiten. This will ensure the best results, as you won't have any forces working against the bleaching.Outside of taking this into consideration, it is important to note the recommended duration for the whitening, as each system differs. Some systems recommend times as short as 15 minutes, while others (such as carbamide peroxide-using systems), recommend keeping the trays/strips in for as long as 6-8 hours. This may also be a deciding factor, as you may want to wear the longer-wear system to bed, depending on your sleep schedule.
