Chin area is considered as a suitable donor site for autogenous bone grafts for alveolar ridge reconstruction before dental implantation. Despite the common use of chin bone grafts, some neurosensory deficiency of the of the lower lip, chin area , gingiva and lower anterior teeth may occur. Purpose: Evaluation of neurosensory deficiency of the lower lip, chin area , gingiva and lower anterior teeth following chin bone harvesting for posterior mandibular alveolar ridge reconstruction.