How long does it take for an adherence to form in the tmj? Is it possible after an arhroscopy to have again adherences formed down? Thank you

Within months . Unfortunately, adhesions in such a small joint space as the TMJ are common. I would discuss this with your omfs. Physical therapy can be of benefit, along with stabilization of the bite with either a bite splint or minor equilibration. Arthrocentesis ( a mini arthroscopy ) as an in office procedure may also help.
Follow up TMJ. I am not an expert on adherences, an oral surgeon could shed more light on this. I suspect that it takes a minimum of 3-6 months, but usually develop over a longer period of time. It is possible that you have have adherences arthroscoped again, but i would discuss the situation with my oral surgeon and my jaw?Tmj dentist before repeating the procedure. Physical therapy could help jaw mobility.
It varies. But they can recurr within a few weeks if you are not moving the joint much. Yes, adhesions can recurr.
Variable. Weeks (in the case of injury) to years. Yes they can recur if you don't keep the jaw moving.