Clinical and Radiographic Evaluation of Subgingival 1% Metformin Gel Versus 0.05% Zoledronate Gel as an Adjunct to MINST of Intrabony Defects in Controlled Type 2 DM

Inclusion Criteria: * Diagnosed with type 2 diabetes mellitus, with HbA1c levels \<7.0% (controlled). * Diagnosis of chronic periodontitis (Stage III/IV, Grade B/C) with at least one intrabony defect of ≥3 mm depth, PPD ≥5 mm, and CAL ≥4 mm measured with a calibrated UNC-15 probe. * Angular bone loss of ≥3 mm measured on digital intraoral periapical radiographs and having three walled intrabony defects without involving furcation confirmed on cone beam computed tomography (CBCT). Exclusion Criteria: 1. Smokers. 2. Pregnant or lactating women. 3. Patients on systemic bisphosphonate therapy or other medications known to affect bone metabolism. 4. Uncontrolled diabetes (HbA1c \>8%) or other systemic diseases that could affect periodontal status. 5. History of radiation therapy to the head and neck