Pro-Enamel works and does help re-build enamal. I have seriously sensitive teeth and after having fillings I couldn't bite down or eat nd drink without pain!
I use it daily and it is fab, i have no pain at all now!
I have very sensitive teeth and have been using a gentle whitening sensydyne. I just changed to Arm & Hammer Enamel Care Sensitive and OMG!!!!!!!! What a huge difference. Run your tongue over your teeth after using and they feel smooth like glass, as though your dentist just polished them. This morning the lights in the bathroom actually reflected off them!!! I'm definitely a believer in this toothpaste AND it's cheaper than what I was using before.
Think the powder is Eucryl, usually ridiculously cheap from Wilko's , Bodycare and similar.
I've used it before and found it pretty good for removing stains and have had my teeth commented on after it. Find it best used with an electric toothbrush though.