On a sliding genioplasty to increase vertical height as 5 mm What is the best material or type of graft for this?

Usually when increasing the vertical chin height by a chin osteotomy of only 5mms, no interpositional graft is needed. The plates and screws fixation will hold the bones apart as they heal the bone gap. Interpositional grafts are usually only used when the vertical elongation is greater and associated with a forward positioning of the chin bone as well.

It is critical to know 'why' you need a 'height increase' as well, since the overall facial proportions also determine the best approach.However, Hydroxylapatite has been valuable for many many years and avoids the added surgical site for securing your own bone. IF the amount of change is small, tilting the chin segment and using a small piece of bone from the jawline works well. The chin area heals ideally due to the extensive blood supply; so many things work well.