Depulpin, is mainly composed of paraformaldehyde, and was widely been used in the past for root canal treatment due to its ease of use. However, its use was prohibited in Korea after several side effects of paraformaldehyde on periodontal tissue were reported. This case report demonstrates a successful dental implant restoration using platelet rich fibrin and recombinant human bone morphogenetic protein-2 for an acute mandibular bone necrosis caused by use of paraformaldehyde-containing paste.