Best to use chemical free products on your skin and anything you’re ingesting like toothpaste. I just brush with water when fasting. The teeth aren’t particularly dirty because I’m not eating. I also use all natural soap, shampoo etc. Let’s face it, we’re cleaning out all the toxins from our body whilst fasting, why put toxins in. Colgate is crap btw. Fluoride is bad for you, and it’s pure chemicals. Invest a little and get a fluoride-free toothpaste that doesn’t have all that crap in it. They’re available everywhere now, even Walmart, Costco etc.