This study aims to construct and systematically evaluate a multifunctional synergistic drug delivery system based on a hyaluronic acid-nanoclay composite hydrogel to achieve integrated treatment of periodontitis encompassing "infection control, inflammation regulation, and bone regeneration promotion." Through material design, in vitro functional validation, and in vivo efficacy evaluation, the study will elucidate the intrinsic relationships and synergistic mechanisms among "material structure, controlled drug release, and biological effects" within this system, thereby providing a theoretical basis and experimental foundation for the development of smart periodontal regenerative materials with clinical translational potential.

Inclusion Criteria:

• Clinical Diagnosis: Meets the 2018 International Classification of Periodontal Diseases, diagnosed with Stage III or IV periodontitis.
• Bone Defect Characteristics: At least one affected tooth presents with a deep periodontal pocket (PPD ≥5 mm), and CBCT imaging confirms the presence of significant vertical bone resorption or angular bone defects (these defect types are most suitable for in-situ hydrogel filling and guided regeneration).
• Age and General Condition: Aged between 18 and 70 years, any gender, generally in good systemic health.

Exclusion Criteria:

• Systemic Interference with Bone Metabolism: Presence of poorly controlled diabetes (HbA1c > 7%), osteoporosis, or long-term use of medications affecting bone metabolism such as bisphosphonates or glucocorticoids within the past six months.
• Local Anatomical Limitations: The affected tooth has a vertical root fracture, severe periapical pathology, or a residual root that is deemed non-restorable and without preservation value.
• Factors Interfering with Healing: Heavy smokers (average > 10 cigarettes per day), as impaired microcirculation can significantly compromise the biological effects of the hydrogel.
• Special Physiological Periods: Pregnant or breastfeeding women.
• Drug Allergy: Known allergy to minocycline (MH), hyaluronic acid (HA), or similar chemical components.