I have a "hole" in one of my molars. It isn't really a hole, but one of my dentists called it that. It's really a chip off the corner. I've had it for about 8 or 9 years and every time I go to the dentist - through moves and 3 different dentists - they say, "Oh, that's a weak spot and we'll probably have to fill it next time." Then when I go back they say the same thing. I guess the enamel chipped off? Anyway, in my case at least, it hasn't caused me any problems and they don't even see the need to fix it.