How long does it take for a hard night guard to stabilize my teeth? I only wear it while sleeping

Long story short, i used to wear a flipper for a missing upper tooth, & apparently i clench my jaw tight while sleeping but the roof of the flipper used to prevent my molars from touching since my bottom teeth used to hit it first, nw that i stopped wearing my flipper at night bcoz i'm in the process of getting a crown after bone graft and an implant, my clenching has gotten much worse (i clench on my molars) my front bottom teeth r moving back & forth, so my dr fabricated a hard night guard