I have heard it said tooth aches never get better on their own. That makes sense, because cavities don't fill back in and cracked teeth don't bond back together.
So, why is the pain and temperature sensitivity gone? One of the back teeth, on the right side of my mouth was forcing me to chew on just one side. That was in December/early January and the other day, I just noticed it was gone. I don't know when it got better. I just know it did.
I would call this a NSV but it seemed to belong here.

Magnesium ?

Sure, I guess. That's as good as any other idea. Has anyone else ever heard of this? Maybe less sugar in my system has relieved some kind of acid atmosphere in my mouth.

Inflammation goes down when the bacteria haven't got the sugar to eat.

Anaerobic bacteria don't need sugar or oxygen to multiply for that matter.
Look up Magnesium and dental health or tooth decay or something along those lines...That is if you're supplementing but if not, never mind.

PS it probably didn't go away but just isn't hitting the nerve right now but it's probably still festering down deep. Now is the time to have it filled before the pain starts again.

I did consider that.