Bests & Worsts Reviews from Amazon

Which ingredient is the one that is helping protect your teeth against the acid erosion? Please don't spoil the surprise by going to the Sensodyne website just yet! I am a retired chemist with too much time on my hands, and I just had to know the answer to this question. OK, the information on the box of this toothpaste states that it "strengthens and re-hardens enamel to help protect against the effects of acid erosion" from liquids such as soda and wine, and acidic foods like tomatoes. Let's start with the inactive ingredients. INACTIVE INGREDIENTS: SORBITOL? no, this is a sugar substitute. HYDRATED SILICA? no, this is an abrasive which helps remove plaque and stains. GLYCERINE? no, this is a humectant that keeps things moist. PEG-8? No, a thickener. COCAMIDOROPYL BETAINE? no, this is a foam booster and emulsifier. FLAVOR? I doubt it. TITANIUM DIOXIDE? no, this is a white pigment. XANTHAN GUM? thickening agent. SODIUM SACCHARIN? no, another sugar substitute, that I didn't think was being used these days. SODIUM HYDROXIDE? whitener. Well, the ingredient is not here, must be one of the "active ingredients". ACTIVE INGREDIENTS: POTASSIIUM NITRATE? The box specifically says this is for hypersensitivity. By the way, this chemical is also used in food preservation, fertilizers, rocket propellants, and gun powder. The major source in nature is bat guano found in caves. Hey, that's a nice little factoid! (If you're ever on Jeopardy). Well, that leaves us with the only other ingredient: FLOURIDE, the same fluoride that is found in almost every toothpaste and in just about the same amount. The box states this is for anti-cavity protection. SO......where is the ingredient that helps protect against acid erosion???? Turns out it IS the fluoride! I had to go to the website to find this out. Yes, the detail in the FAQ section states: "The sodium fluoride ion helps reverse the process (of acid erosion) by "re-mineralizing" the tooth enamel which has been previously damaged". "It re-hardens softened enamel by restoring lost minerals", IT DOES NOT PHYSICALLY REPAIR LOST ENAMEL". Does this sound contradictory to you? It does to me. It "restores the minerals" but does not "repair the lost enamel". HUH? DIRECTIONS FOR USE: The suggested method of use is equally strange, although perhaps logical. It suggests that we DO NOT brush immediately after eating or drinking acidic foods because that is when the teeth are softest. We are told to wait at least an hour, or better yet, brush BEFORE meals. CONCLUSION This has been fun (for me at least), and I will continue to use Sensodyne brand toothpaste, even knowing that it contains no special, secret ingredient that will magically restore my enamel to the condition it was in my youth. I guess it never did say that anyway. It is enough that this is very effective in diminishing the sensitivity I have, which of course is due to the acid erosion over the years. If it also "gently whitens" my teeth, that will be a plus.