On the former, I talked to dentists on both sides of the Atlantic. First, the clinical categories.
Some toothpastes boast higher fluoride concentrations than others, but the difference is negligible.
Most dentists agree that if it's got fluoride and it's approved by the American Dental Association, you can't go wrong with it. But while it's true that any fluoride toothpaste will do a fine job, certain clinical distinctions may help you choose your weapon. Some toothpaste claims are bogus, but others are for real. Tartar control toothpastes can't remove tartar, but they can stave it off. This works for people with receded gums.