Although the All-on-4 comes with fewer complications, as is the case with any surgical procedure, it can carry a few possible risks and side effects. Minor discomfort, swelling, and bruising are relatively common post-procedure and are usually manageable with over-the-counter painkillers. They should subside within a few days. There are potentially more severe issues like infections around the implant site, nerve damage, and sinus complications with implants placed in the upper jaw.
However, these are quite uncommon. An improperly carried out procedure can cause the implants not to fuse with the bone or become loose, and certain lifestyle habits or medical conditions can increase complications or implant failure.