The biofilm in the mouth grows most overnight due to closed mouth, reduced saliva flow, and low oxygen.

“but all those reasons that i said your mouth is closed no oxygen — reducing saliva flow salivary flow is almost zero because you're sleeping and things like so people when you wake up you feel if you stop and thinking you're gonna see yes my mouth is dry if you cross your tongue on the surface of your cheek you're gonna feel the biofilm that's the only the biofilm is invisible to your eyes but you can feel with your tongue that's the morning that you're gonna see okay so there's nothing wrong”