I woke up this morning and noticed that i had like a chip/missing tooth, it's more like a big chip in my Premolar (i think it's that one)

Anyway, the tooth wasn't loose and there was no pain and there still isn't any pain now or blood. The roots aren't there but there's still a bit of the tooth left, a bit like a flat base.

Any ideas how it's managed to come out over night? And should i go to the dentist just to make sure it's ok?
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Additional Details
Just to add a few details, i have no baby teeth left, and it's one of my Molars that's chipped at the back.