Thank you for your question and welcome to Just Answer.
One of two things has happened. Either a small piece of your tooth that surrounds the filling has chipped away or a small piece of the filling has chipped off. Both situations will give you the rough feeling that you now observe.
If the chip is small enough that does not expose the secondary level of the tooth structure, then it is possible that this can be treated by just smoothing of the rough edge. If too much tooth structure has chipped away, you might have to have the filling replaced with one that incorporated the new missing piece.
I hope this answers your question. If you would like to discuss this further or have any additional questions, please reply to my answer and I will get right back to you.
Sincerely, XXXXX XXXXX DDS
If the filling on the other tooth that you descrie is a white filling, then it did not grow over and overlap the tooth. Your dentist accidentally left the overlap when the filling was initially placed, a piece of theoverlap broke ooff, and he then smoothes it back to proper contours when you noticed the rough edge.
If the filling on the other tooth that you descrie is a silver filling, then it is possible that this old filling started expanding, creating the rough edge that you noticed. In this situation, smoothing off the expanded edge solved the problem.
This might be the exact thing that is happening now. I hope this helps.
Then the chip is small enough, all it needs is to be smoothed off. I hope this helps. Please reply is you have any other questions related to this matter.
You are most welcome. I wish you well.