Mystery Tooth

So Isabelle has been teething for a couple weeks now.  Last week one of her top front teeth graced us with its presence.  It was fully in... and it wasn't pretty.  It looked a little more like a fang  pointing in an awkward direction than a front tooth.  My beautiful girl now had something not so beautiful about her.  Fortunately when she smiles you don't usually see the top gums.  Charles was still in Atlanta at the time, so I made sure I prepared him for what he was about to come home and see.  Well Thursday night I put Isabelle to bed early (6:30) and she didn't get up till 8:30 or so the next morning.  To my amazement the tooth had vanished.  Completely gone!  I called my mom and asked if that was possible.  Her theory was that maybe the other front tooth was coming in and it was pushing the gums down back over the tooth or maybe the gums were swollen.  Well now we are about five days later and that tooth is still gone, but a new tooth is coming through in the same spot.  But I am positive that it is not the same tooth because this one looks nice and flat, not pointy at all.  I guess we'll see when it comes all the way in.  In any case I still wonder what happened to the mystery tooth.  Any thoughts?