Can I whiten my teeth overnight? Is it safe to have whitening gel on my teeth for 6-8 hours?

Hi:Most of the whitening systems have moved away from over night whitening.  It is now 30 mins to one hour each time to prevent sensitivity.Best,Dr. Maddahi

There are a number of different whitening gels to choose from, some stronger than others. In my office, the whitening gel I use is intended for overnight use. Depending on the concentration of your particular gel, you might be able to use it overnight if that's what it's intended for. If it's too strong, you should not use it overnight. 

Most of the current gels for whitening are for shorter term use. Some are as short as 30 minutes. Wearing them overnight is not a good idea.