Where My Teeth Go

[bisurge]

Before, when I bite down, my upper front teeth always went in front of my bottom front teeth.
For some reason, starting Friday, one of my upper front teeth always goes behind my bottom front teeth.
Why did this happen, and is this a problem?

[bisurge]

Oh, and that is when I try to put my upper teeth above my lower teeth.
When I bite down normally in a relaxed position, both my upper teeth go behind my lower teeth.