How long does it take for your teeth to shift? How long should I wait for a bridge or possibly a dental implant? (Photo)

I had a mandibular left first molar extracted last year. Because it was the one in the center, I have molars on both sides of the gap. In May of this year, I had my dental bridge removed due to gum inflammation. My dentist left and a new one came instead, she didn't want to order a bridge so she did this (see picture) because it looked nicer (and not functional at all, not one day goes by and it already broke) so until I get a new one how long would it take for my teeth to shift?