I agree lots of scent comes from your mouth and brushing with something has to help.
Here is my .02.....
Anything to help my odds is just that helping my odds.
Why do we wear camo? Why do we use rangefinders? Why do we wear insulated cloths when its cold? Why do we get bigger more comfy stands?
We do all this to help our odds of kill a deer and staying in the stand longer.
SO brushing my teeth with scent free toothpaste is just another thing. Going to brush my teeth anyways so might as well use something that could help my odds while hunting.