I have coffee stained teeth. I also have periodontal disease and am having treatment done on April 1st and April 8th. I know once you have periodontal disease, you'll always have it. So I'll be having deep cleanings 4x a year. I would like to whiten my teeth, but am paying out of pocket. So zoom whitening will probably not be within my budget. I know that some people see good results with crest whitestrips. My question is are they safe to use after my periodontal disease is treated?