For better occlusion, the implant should be shorter (5x8.5 mm) after discussion with the guide lab (Fig.9).  Make sure that the most coronal thread is buried by the bone graft, i.e., underneath the crest (>).

1) The level of implant may vary from different cases and from different implant systems. However this case was designed to be just the same level as the bone level (inside the bone material) in order to get more fixation at the apex and to prevent getting closer to the nerve.
2) Yes, peri implantitis can be developed at the bone grafted area as well just like as the natural bone. As any infections happen around the cortical part of implant resulting bone loss is defined as Peri implantitis, therefore bone grafted area is not an exception for that. As bone material has been integrated with the natural bone, even though it is weak, it still is classified as bone forming one. Therefore bone graft area is more vulnerable to the infections of peri implantitis.
Hope this answers your question.

Ridge Preservation

Xin Wei, DDS, PhD, MS 1st edition 04/10/2018, last revision 04/17/2018