The influence of exogenous nerve growth factor on inferior alveolar nerve regeneration in silicone tubes.

OBJECTIVE: To explore the effects of exogenous nerve growth factor (NGF) in the regeneration of adult white rabbit inferior alveolar nerves within silicone tubes.

METHODS: Twenty-four adult white rabbits were selected. Bilateral 8 mm inferior alveolar nerve gaps were created, and the proximal and distal stumps were inserted into a 12 mm silicone tube. The right side silicone tube was filled with exogenous NGF (experimental group) and the contralateral side was filled with saline (control group). Regeneration of the nerves was assessed by histological and nerve eletrophysiological observation. Total number of the regenerated myelinated fibers, conduction velocity of the nerves, thickness of myelin sheaths, and cross-section area of myelinated nerve fibers between the experimental and control groups were compared.

RESULTS: The results show that NGF significantly increased the number of myelinated fibers. The experimental group demonstrated more myelinated fibers than the controls at 12 and 18 weeks. At the same time following surgery, the myelin sheath thickness and the cross-section area of myelinated fibers in the experimental group were significantly greater than those in the controls. At 12 and 18 weeks, the conduction velocity of regenerated nerves in the experimental group were greater than those of the control.

CONCLUSION: This study suggests that exogenous NGF can enhance regeneration of the inferior alveolar nerves and recovery of their sensory function.