A = partial implant intrusion into mandibular canal can cause direct mechanical IAN trauma - encroach, or laceration and primary ischemia.
B = full implant intrusion into mandibular canal can cause direct IAN transection, and/or compression and primary ischemia.
C = dental implant is too close to the mandibular canal, it can cause IAN compression.
D = partial implant intrusion into mandibular canal can cause indirect trauma due to hematoma and secondary ischemia.
E = partial implant intrusion into mandibular canal can cause indirect trauma due to bone debris and secondary ischemia.
F = "cracking" of the IAN canal roof by its close proximity to preparation of the implant bed. It can cause compression and primary ischemia.