I had root canal treatment and on my two upper central incisors. This was a few months ago and the crowns that were put were either porcelain or ceramic (I'm unsure). They don't contain any metal. I've noticed recently that they move slightly more than my other teeth (Not visible movement). I was wondering if it is the crowns that are moving or my natural teeth under the crowns. I have been taking good care of them. I don't bite into anything hard. Does the movement mean that they'll fall off?