I just saw this thread, but wanted to pass on this product. I have gum disease, and this is the floss my dentist told me to use. It stretches to fit into tight spots, but puffs up to clean in larger gaps. It's also more effective, but gentler on my gums than any other floss I've used. I don't use the Crest branded one, but I imagine it's very similar (mine comes from my dentist).
As the arc of history bends towards justice, it's a new, more progressive day. --Steve Benen, The Maddow Blog, 11-07-12