About a year ago I had my front 6 teeth crowned. In this year I've had two break in the middle of the night through contact with my bottom teeth, the second being very recent. My dentist fixed the first by filing down the tooth that could touch when I bit and told me that I have an abnormal grinding problem. I've never had any grinding issues until after having these crowns. Is it normal to develop a grinding issue like this after getting crowns? Or is this a different issue?