grinding. When can I bleach my teeth? I want to bleach, but I don't want to do it too soon because I know that it will cause increased sensitivity on top of the sensitivity I've already been experiencing due to my grinding. I just started using my night guard about four nights ago. I've worn it consistantly (surprisingly) and do not remove it during the night. I have noticed a markable decrease in my sensitivity, but I would like to know when I can start bleaching my teeth.