I am a Dental Hygienist. Here is what I recommend to my patients.
The home flouride treatments may be all you need to achieve the results you desire ie: white strips,trays. The active ingredient is the carbamide peroxide. The higher the percentage is stronger.However,bleaching can cause sensitivity. You may want to use a sensodyne product a few days prior and during the process.Advil or Tylenol also helps if pain is experienced due to recession areas, sensitive tissue etc. Rembrandt makes a good whitening toothpaste which is kind to your mouth.
White fillings or crowns WILL NOT bleach.