Electrotome is frequently used for surgical treatments in the field of dentistry and oral surgery. We report a rare case of gingival and alveolar bone necrosis caused after gingivectomy with electrotome. The patient was a 30-year-old female complained of gingival discolor. She noticed the gingival discoloration 2 days after the gingivectomy with electrotome by her family dentist. The gingiva around the left upper central incisor was changed to white in color. Nine days after the electrosurgery, the left upper central incisor fell off spontaneously, and 7 weeks after the electrosurgery, the sequester was removed. Epithelization was completed 2 weeks after the sequestrectomy, and she was successufully treated by the fixed bridge and removable artificial gingiva.