Treatment for severe vertical bone resorption in periodontal tissue regeneration therapy includes the recently developed recombinant human FGF-2 therapy (REGROTH Ⓡ ), bone graft, guided tissue regeneration (GTR), and enamel matrix proteins (Emdogain Ⓡ gel). We report an excellent long-term outcome in a patient with severe chronic periodontitis (stage IV, grade B ) with secondary occlusal trauma, who underwent periodontal tissue regeneration therapy using artificial bone (hydroxyapatite: HA) grafting and hemisection.The patient had malocclusions but suitable plaque control. However, seven years after the start of SPT (supportive periodontal therapy), the patient underwent long-term chemotherapy for cancer, which caused temporary taste disorder, but no onset of stomatitis. Eighteen years after the bone grafting, the HA remains without radiographic replacement or resorption, and there are no functional problems, it has not been a source of infection, and there have been no acute symptoms or periodontal pocket progression. We believe that thorough plaque control effectively maintains periodontal tissue after periodontal surgery and the oral environment during chemotherapy. We concluded that complete plaque control effectively maintains periodontal tissue after periodontal surgery and the oral environment during chemotherapy.