Fonty
I don't know if it does or not. Toothpaste is designed supposed to taste sweet-ish though, whereas bi-carb isn't trying to mimic a food and is more like eating chalk I'd imagine- so not tasting like a food it would be less likely to stimulate the digestion I'd imagine.
I don't use toothpaste fasting or not, I just brush with water only. The brushing on it's own does the job well enough. Electric toothbrushes are pretty cool too I'm sure they make the brushing more effective.
Andrew.