I've done this too! Just lay down the dental floss and zig zag over it taking care to not catch it in your thread. Then you just draw it up as much as you want. It won't break like regular thread and goes so quick! I keep a package of floss in my sewing box for this at all times!
I have done this with any heavier thread. Even button and carpet thread to zig zag over. Works very well. Is very adjustable.