Thank you for your question.
Well it really depends on the source and nature of your tooth sensitivity as the approach may be very different for different circumstances. We would not be able to say for certain without some form of prior clinical examination by your dentist.
In general, my patients do find that take-home whitening tends to cause less sensitivity but again, this really depends on what the source of your sensitivity is in the first place.
After whitening, we would expect teeth to stay white for at least a year or more on average before some touch-up may be needed. This of course varies very much with your lifestyle and diet as well.
Reference: http://www.tpdental.com.sg/teeth-whitening/
