Thanks, Roland for your comments. Yes, the graph (I assume you refer to the last graph in the post) is simply to illustrate an N-of-1 experimental result. N-of-1 entails more than the graph shows. What we do is to compare control periods (no nitrate) with intervention periods (nitrate) and compare the periods with algorithms sensitive enough to detect the significance of differences. We have built this as a web application for lay-persons to use. The graph simply illustrates the intervention period. As far as the toothpaste is concerned, I believe we can reverse-conclude (or assume) that toothpaste does not have the same effect as mouthwash. Because subjects that uses mouthwash lacked the bacteria, even though they carried on with their regular dental hygiene. But it is definitely worth testing.