What caused space (halo) around implant?

Thank you for your inquiry. Without seeing an x-ray it's difficult to determine what the actual "halo" is from, but in general this type of translucency observed on an x-ray is caused by a sign of infection. Infection could be from bacteria due to hygiene or treatment, an improper bite (your crown on top of the implant was hitting on another tooth thus causing stress of your implant), your body rejecting the implant and/or bone graft, etc. In any case, it's good that your implant was removed and another bone graft placed. It may take more time than the last to ensure your bone graft integrates successfully into your jaw, but only then can it be re-evaluated to see if another implant can be placed in the future. We hope this helps and we wish you all the best!

The "halo" around a failed implant could be a sign of infection or failure of the bone to integrate.  The overall success rate of dental implants is about 95%, so failures are not common.  I'm sorry you had one of the few that did!  Some causes of implant failure are inadequate oral hygiene, smoking, trauma from occlusal forces or a compromised implant.  The best defense against implant failure is good communication with your surgeon and restorative dentist as well as proper aftercare during the healing process.

Implants can fail for many reasons and it would be helpful for you to upload a pic of the X-ray. Hopefully your surgeon figured out the reason before redoing the implant so it does not fail again. All the best.