In the distal stump of injured peripheral nerves, Wallace degeneration occurs and the neurolemmal cells dedifferentiate and proliferate. Phagocyte pieces are also present in injured nerve ends, and factors are secreted to increase the amount of phagocytes in the e injured area and remove disintegrating myelin debris. Thus, neurolemmal cells guide axis regeneration, cover axon, and form myelin. In the early wound healing process after implanting operation, peri-implant neurofilament protein staining positive fibers and regenerated nerve fibers are the basis of oral sensation responses for implant patients. The microscale structure of different titanium surfaces is beneficial for the attachment and proliferation of nerve cells and secretion of nutritional factors. Nerve growth factor is essential for the growth and survival of sympathetic and sensory neurons. Heparin-conjugated fibrin gel implants and hydroxylapatite nerve growth factor composite coating titanium implants can release active nerve growth factors sustainably, promote nerve cell proliferation and regeneration, and improve early osseoperception of the implant. The mechanisms of how the microstructure and chemical composition promote peripheral nerve regeneration, as well as the relevant molecular mechanism, require further research.
