How long will temporary all on four implants last?

Hi:The longevity of your temporary all on 4 is mainly dependent on your diet.  It's best to avoid hard and crunchy food. I also recommend cleanings every 3-4 months.Best,Dr. Maddahi

Your temporary denture should be good for about 6-8 months. Of course you want to use common sense and stick to a more bland diet, nothing that would make your dentures chip or fracture. You do not want to eat or do anything that would compromise the denture or implants while you heal.
At my clinic sometimes we send our All on 4 patients home with a PMMA temporary bridge designed and milled with CAD/CAM technology. This way our patients have a second bridge in the case the original one breaks or fractures during the osseo integration period.