Wonder what this will do for those that have periodontal disease?
Probably very little, as it does nothing for anywhere other than the surface of the tooth above the gumline.
I eliminated periodontal disease from my vocabulary (and I had LOTS of problems, despite regular brushing and lossing) with a very simple approach that anyone can use.
Go to your local sewing store and buy a skien of nine-strand embroidery thread (the kind that comes wrapped like shoelaces). Then go to your local drugstore and buy a spool of fine, unwaxed dental floss, and a bottle of hydrogen peroxide.
Take the skien of embroidery thread and cut across one end, so you have "half-loops" of embroidery thread. Now cut off about eighteen inches of dental floss, double it, and knot the free ends, forming a full loop. Wrap the dental floss around whichever "anchor finger" you normally use while flossing (the end with the knot should be next to the finger, with the loop end hanging free). "Thread" the half-loop of embroidery thread through the open loop of the dental floss with the ends dangling. Dip the embroidery thread in the hydrogen peroxide.
Now, thread the dental floss between two teeth, and use it to pull the embroidery thread into the gap between the teeth (the embroidery thread is too wide to slide through the small gap at the top of teeth, but the gap is wider at the bottom). "Rub" the peroxide-coated e-thread on the surface of the teeth right at (and as far below) the gum-line as you can stand). Curve the e-thread around as much tooth surface as convenient---you can't get it all, but capillary action "draws" some peroxide along the rest of the gum-line
Switch to the next pair of teeth. Refresh the hydrogen peroxide dip after doing a quadrant of your teeth.
This also works with Listerine, or as a poster up-thread recommended, Dr. Tichenor's (and I suspect anything that kills bacteria will work). My wife prefers Listerine.
I have now used this approach for quite a few years, and i have ZERO problems with gums. In fact, my dental technician regularly tells me what great shape they're in.
But before finding this, I was the "poster-boy" for bleeding gums when getting teeth cleaned (which I was having done every four months instead of every six). I had also tried the e-thread/floss trick without the peroxide, and it just simply isn't even remotely as effective.
And yes, this is all anecdotal data, but I have gone "on and off" using the peroxide as a statistical data gathering approach, and the difference is VERY reproducible.