I went to John Hart a while ago. He has a fancy machine that finds small variations in tooth structure; he then calls them cavities and wants to fill them. I got suspicious when he said my mouth had multiple cavities when I had had only one or two before in my life. In my view (and in the view of the dentist I went to afterward) he wanted to drill into what were perfectly good, cavity-free teeth. Don't let him do it--stay far away!