Usually defected alveolar bone gives limitation for Implantation. To overcome this problem surgeons developed several ways. Ridge separation, distraction osteogenesis (DO), block bone graft, etc.

But indication of ridge separation is only for horizontal bone resorption, and distraction osteogenesis is so difficult procedure for both surgeons and patients and it also has very limited indication. Because of these reasons in most of bone augmentation cases we must consider for bone graft. And especially block bone graft is useful for most of augmenting cases.

There are many sources for block bone harvest, illiac bone, calvarium, rib bone for extraoral site and chin, ramus, maxillary tuberosity for intraoral site. Each site has its advantage and disadvantages.

Chin has many advantages. Easy for access, abundant bone can be obtained, both block bone and cancellous bone can be harvested, less morbidity, need not hospitalization, and less resorption after graft, etc. But some times sensory disturbance or numbness may occur and it is the main problem with chin bone graft. And other reported complications are wound dehiscence, prolapse of lip, bruise on chin area, etc.

In spite of these complication, chin bone is most convenient and useful donor site for augmenting resorbed alveolar bone. If we have knowledges about the anatomy and physiology around the chin, most of complication with bone harvesting could be prevented.

We studied for anatomical variation of incisive nerves and incision line for reducing complication and report with some clinical cases.

Conflict of interest: None declared.