This whole story illustrates why I floss 2x a day, brush with Sonicare, and just hope for the best. I've never trusted any dentists. Think about it -- who becomes a dentist?
But seriously, there is no way this missive is going to turn into anything. Alolouf or whatever his name is probably spent a pretty penny just to get a lawyer to write you that letter on her stationery. He almost certainly thought that as soon as you received it, you would fall like a deck of cards. Little did she know about you.
But to take futher steps on a frivoulous claim, to the tune of thousands upon thousands of dollars? When this dentist is already in some financial difficulty? No, I don't think so.