This seems to talk about what might happen to lemon juice after some digestive process. I googled pH of lemon juice and several sites make reference to a pH of around 2-3. That's acid and the teeth would see that since the lemon juice isn't digested when it hits the teeth.
What I do is either rinse my mouth out with water or baking soda (sodium bicarbonate) in water depending on whether I'm at home or not. I also alternate swigs of lemonade with water since I've got two containers with me on my desk.
I also saw an earlier thread where they talked about the difference between drinkin lemon juice and biting lemons. Apparently biting lemons might be worse. I don't remember the details but I know it's in the forum messages.
Day 12 for me. THis morning I'm preferring the maple syrup over the molasses which is unusual. I haven't weighed in about a week but the belt is looser and I feel quite a bit lighter and have more energy. My food cravings/obsessions aren't as all emcompassing as they were on day 9/10. I'm drinking about 6-8 aday with LOTS of water. Thanks for this great forum.