Systematic Oral Hygiene Intervention for the Prevention and Control of Oral Mucositis During the Perioperative Period of Pediatric Hematopoietic Stem Cell Transplantation: A Prospective, Randomized Controlled Clinical Trial

INTERVENTION: Intervention group:Systematic oral care intervention;Control group:Routine oral care; CONDITION: Hematopoietic stem cell transplantation; Oral mucositis PRIMARY OUTCOME: Incidence of oral mucositis; SECONDARY OUTCOME: Oral mucositis pain score;severity of oral mucositis;Changes in salivary IL‐6 and IL‐1ß levels;Length of hospital stay and medical costs;Duration of oral mucositis; INCLUSION CRITERIA: 1.Patients aged <=18 years who are scheduled to undergo their first HSCT at our center; 2.Patients with confirmed HSCT indications, including but not limited to acute leukemia, severe aplastic anemia, and thalassemia; 3.Patients are expected to complete baseline oral assessment and intervention within 1 week before HSCT. 4.Stable baseline oral status, defined as WHO grade 0 oral mucositis, with no active oral ulcers, herpetic gingivostomatitis, acute necrotizing ulcerative gingivitis, or untreated odontogenic abscesses. 5.The legal guardians of pediatric patients understand the study procedures and voluntarily sign the informed consent form.